data_type large_stringclasses 3
values | source large_stringclasses 29
values | code large_stringlengths 98 49.4M | filepath large_stringlengths 5 161 ⌀ | message large_stringclasses 234
values | commit large_stringclasses 234
values | subject large_stringclasses 418
values | critique large_stringlengths 101 1.26M ⌀ | metadata dict |
|---|---|---|---|---|---|---|---|---|
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Once we refactor move_folios_to_lru(), its callers will no longer have to
hold the lruvec lock; For shrink_inactive_list(), shrink_active_list() and
evict_folios(), IRQ disabling is only needed for __count_vm_events() and
__mod_node_page_state().
To avoid using local_irq_di... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:37 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In a subsequent patch, we'll reparent the LRU folios. The folios that are
moved to the appropriate LRU list can undergo reparenting during the
move_folios_to_lru() process. Hence, it's incorrect for the caller to hold
a lruvec lock. Instead, we should utilize the more gener... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:38 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
To allow LRU page reparenting, the objcg infrastructure is no longer
solely applicable to the kmem case. In this patch, we extend the scope of
the objcg infrastructure beyond the kmem case, enabling LRU folios to
reuse it for folio charging purposes.
It should be noted tha... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:39 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
Memory cgroup functions such as get_mem_cgroup_from_folio() and
get_mem_cgroup_from_mm() return a valid memory cgroup pointer,
even for the root memory cgroup. In contrast, the situation for
object cgroups has been different.
Previously, the root object cgroup couldn't be ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:40 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:41 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:42 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:43 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:44 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:48:45 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In __fo... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:52:56 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:52:57 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:52:58 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. To ensure safety, it will only be appropriate to
hold the rcu read lock or acquire a reference to the memory cgroup
returned by folio_memcg(), thereby preventing it from being released.
In the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:52:59 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
In the near future, a folio will no longer pin its corresponding memory
cgroup. To ensure safety, it will only be appropriate to hold the rcu read
lock or acquire a reference to the memory cgroup returned by
folio_memcg(), thereby preventing it from being released.
In the c... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:00 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
In the near future, a folio will no longer pin its corresponding memory
cgroup. To ensure safety, it will only be appropriate to hold the rcu read
lock or acquire a reference to the memory cgroup returned by
folio_memcg(), thereby preventing it from being released.
In the c... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:01 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. So an lruvec returned by folio_lruvec() could be
released without the rcu read lock or a reference to its memory
cgroup.
In the current patch, the rcu read lock is employed to safeguard
against... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:02 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. So an lruvec returned by folio_lruvec() could be
released without the rcu read lock or a reference to its memory
cgroup.
In the current patch, the rcu read lock is employed to safeguard
against... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:03 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. So an lruvec returned by folio_lruvec() could be
released without the rcu read lock or a reference to its memory
cgroup.
In the current patch, the rcu read lock is employed to safeguard
against... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:04 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
In the near future, a folio will no longer pin its corresponding
memory cgroup. So an lruvec returned by folio_lruvec() could be
released without the rcu read lock or a reference to its memory
cgroup.
In the current patch, the rcu read lock is employed to safeguard
against... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:05 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Now we have lruvec_unlock(), lruvec_unlock_irq() and
lruvec_unlock_irqrestore(), but no the paired lruvec_lock(),
lruvec_lock_irq() and lruvec_lock_irqsave().
There is currently no use case for lruvec_lock_irqsave(), so only
introduce lruvec_lock_irq(), and change all open-... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:06 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
The following diagram illustrates how to ensure the safety of the folio
lruvec lock when LRU folios undergo reparenting.
In the folio_lruvec_lock(folio) function:
```
rcu_read_lock();
retry:
lruvec = folio_lruvec(folio);
/* There is a possibility of folio repar... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:07 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
To resolve the dying memcg issue, we need to reparent LRU folios of child
memcg to its parent memcg. For traditional LRU list, each lruvec of every
memcg comprises four LRU lists. Due to the symmetry of the LRU lists, it
is feasible to transfer the LRU lists from a memcg to ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:08 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Similar to traditional LRU folios, in order to solve the dying memcg
problem, we also need to reparenting MGLRU folios to the parent memcg when
memcg offline.
However, there are the following challenges:
1. Each lruvec has between MIN_NR_GENS and MAX_NR_GENS generations, t... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:09 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Refactor the memcg_reparent_objcgs() to facilitate subsequent reparenting
LRU folios here.
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@o... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:10 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
For cgroup v2, count_shadow_nodes() is the only place to read
non-hierarchical stats (lruvec_stats->state_local). To avoid the need to
consider cgroup v2 during subsequent non-hierarchical stats reparenting,
use lruvec_lru_size() instead of lruvec_page_state_local() to get t... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:11 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
To resolve the dying memcg issue, we need to reparent LRU folios of child
memcg to its parent memcg. This could cause problems for non-hierarchical
stats.
As Yosry Ahmed pointed out:
```
In short, if memory is charged to a dying cgroup at the time of
reparenting, when the ... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:12 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Convert objcg to be per-memcg per-node type, so that when reparent LRU
folios later, we can hold the lru lock at the node level, thus avoiding
holding too many lru locks at once.
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
include/linux/memcontrol.h | 22 +++++... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:13 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
Now that everything is set up, switch folio->memcg_data pointers to
objcgs, update the accessors, and execute reparenting on cgroup death.
Finally, folio->memcg_data of LRU folios and kmem folios will always
point to an object cgroup pointer. The folio->memcg_data of slab
... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:14 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Muchun Song <songmuchun@bytedance.com>
We must ensure the folio is deleted from or added to the correct lruvec
list. So, add VM_WARN_ON_ONCE_FOLIO() to catch invalid users. The
VM_BUG_ON_PAGE() in move_pages_to_lru() can be removed as
add_page_to_lru_list() will perform the necessary check.
Signed-off-by: Muchu... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 15:53:15 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | From: Qi Zheng <zhengqi.arch@bytedance.com>
Convert objcg to be per-memcg per-node type, so that when reparent LRU
folios later, we can hold the lru lock at the node level, thus avoiding
holding too many lru locks at once.
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
changlog:
- fix a missing root_obj_cg... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Wed, 25 Feb 2026 17:44:56 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | Did you measure the impact of making state_local atomic on the flush
path? It's a slow path but we've seen pain from it being too slow
before, because it extends the critical section of the rstat flush
lock.
Can we keep this non-atomic and use mod_memcg_lruvec_state() here? It
will update the stat on the local counter... | {
"author": "Yosry Ahmed <yosry@kernel.org>",
"date": "Wed, 25 Feb 2026 06:58:59 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, 25 Feb 2026 15:48:33 +0800 Qi Zheng <qi.zheng@linux.dev> wrote:
Thanks, I've added this to mm.git's mm-new branch.
All being well I'll move it into the mm-unstable branch a few days hence.
Then into mm-stable around -rc5.
Then into mainline for 7.1-rc1. | {
"author": "Andrew Morton <akpm@linux-foundation.org>",
"date": "Wed, 25 Feb 2026 13:57:06 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, Feb 25, 2026 at 06:58:59AM -0800, Yosry Ahmed wrote:
Qi, please measure the impact on flushing and if no impact then no need to do
anything as I don't want anymore churn in this series.
Yosry, do you mind sending the patch you are thinking about over this series? | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Wed, 25 Feb 2026 16:25:27 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, Feb 25, 2026 at 03:53:12PM +0800, Qi Zheng wrote:
[...]
The above seems like addition by mistake.
After fixing this, you can add:
Acked-by: Shakeel Butt <shakeel.butt@linux.dev> | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Wed, 25 Feb 2026 17:41:46 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, Feb 25, 2026 at 05:44:56PM +0800, Qi Zheng wrote:
The layout of struct mem_cgroup_per_node is very performance sensitive. Please
couple of performance benchmarks after rearranging the fields particularly the
above two pointers together at the start of the struct.
Otherwise:
Acked-by: Shakeel Butt <shakeel.bu... | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Wed, 25 Feb 2026 18:27:59 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, Feb 25, 2026 at 03:53:14PM +0800, Qi Zheng wrote:
Acked-by: Shakeel Butt <shakeel.butt@linux.dev> | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Wed, 25 Feb 2026 18:40:07 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | Hi Yosry,
On 2/25/26 10:58 PM, Yosry Ahmed wrote:
No, because this is not a performance-critical path, I did not perform
performance testing. :(
Got it. Do you have any test cases that previously identified this
problem?
Thank you for providing optimization ideas; I will take a closer look. | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Thu, 26 Feb 2026 14:41:28 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On 2/26/26 10:27 AM, Shakeel Butt wrote:
Got it, will try to do it. Additionally, it would be even better if
there were existing test cases available. ;)
Thanks! | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Thu, 26 Feb 2026 14:47:14 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | Honestly, I'd rather squash it into this patch if possible. It avoids
churn in the history (switch to atomics and back), and is arguably
simpler than checking for regressions in the flush path.
What I have in mind is the diff below (build tested only). Qi, would
you be able to test this? It applies directly on this pa... | {
"author": "Yosry Ahmed <yosry@kernel.org>",
"date": "Thu, 26 Feb 2026 07:16:50 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Thu, Feb 26, 2026 at 07:16:50AM -0800, Yosry Ahmed wrote:
Yup, let's squash it into the original patch. Please add your sign-off tag.
Qi, please squash this diff into the patch and test. You might need to change
the subsequent patches. Once you are done with testing, you can post the diffs
for those in reply to t... | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Thu, 26 Feb 2026 09:02:40 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Thu, Feb 26, 2026 at 9:03 AM Shakeel Butt <shakeel.butt@linux.dev> wrote:
Sure. Qi/Andrew, feel free to add these tags if you squash the diff below:
Co-developed-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
FWIW, after applying this diff, the rest of the series applies
cleanly... | {
"author": "Yosry Ahmed <yosry@kernel.org>",
"date": "Thu, 26 Feb 2026 09:13:35 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, Feb 25, 2026 at 05:44:56PM +0800, Qi Zheng wrote:
After this patch, do we care that page/folio/slab points to the objcg of the
same node as them for a given memcg? | {
"author": "Shakeel Butt <shakeel.butt@linux.dev>",
"date": "Thu, 26 Feb 2026 12:05:51 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On Wed, 25 Feb 2026 13:57:06 -0800 Andrew Morton <akpm@linux-foundation.org> wrote:
Great. I found the commit message on mm-new lacks the conventional "This patch
(of X):" line, though. Andrew, could you please add that line?
Thanks,
SJ
[...] | {
"author": "SeongJae Park <sj@kernel.org>",
"date": "Thu, 26 Feb 2026 16:24:05 -0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | Hi Yosry,
On 2/26/26 11:16 PM, Yosry Ahmed wrote:
Thank you so much for doing this! I'm willing to squash and test.
And I found some issues with the diff:
We can't use mod_memcg_lruvec_state() here, because child memcg has
already been set CSS_DYING. So in mod_memcg_lruvec_state(), we will
get parent memcg.
It se... | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Fri, 27 Feb 2026 11:11:57 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On 2/27/26 11:11 AM, Qi Zheng wrote:
Since child memcg is about to disappear, perhaps we can just add value
to parent memcg without handling the child memcg. Make sense? | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Fri, 27 Feb 2026 14:05:56 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | From: Qi Zheng <zhengqi.arch@bytedance.com>
Changes in v5:
- fix build error in [PATCH v4 24/31] (reported by kernel test robot)
- move the declaration of reparent_memcg_state_local() and
reparent_memcg_lruvec_state_local() into mm/memcontrol-v1.h file.
(suggested by Shakeel Butt, and due to some function depe... | null | null | null | [PATCH v5 00/32] Eliminate Dying Memory Cgroup | On 2/27/26 4:05 AM, Shakeel Butt wrote:
Maybe not. My only concern is whether the kernel has a way of
determining whether two folios belong to the same memcg by checking if
the objcg pointers are equal. If so, it needs to be changed to check if
objcg->memcg are equal. | {
"author": "Qi Zheng <qi.zheng@linux.dev>",
"date": "Fri, 27 Feb 2026 14:34:49 +0800",
"is_openbsd": false,
"thread_id": "e15c2304-4874-4adc-bbe5-58ba78b3b84f@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | N_MEMORY nodes are intended to contain general System RAM. Today, some
device drivers hotplug their memory (marked Specific Purpose or Reserved)
to get access to mm/ services, but don't intend it for general consumption.
Create N_MEMORY_PRIVATE for memory nodes whose memory is not intended for
general consumption. Thi... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:16 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | N_MEMORY_PRIVATE nodes hold device-managed memory that should not be
used for general allocations. Without a gating mechanism, any allocation
could land on a private node if it appears in the task's mems_allowed.
Introduce __GFP_PRIVATE that explicitly opts in to allocation from
N_MEMORY_PRIVATE nodes.
Add the GFP_PR... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:17 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Various locations in mm/ open-code cpuset filtering with:
cpusets_enabled() && ALLOC_CPUSET && !__cpuset_zone_allowed()
This pattern does not account for N_MEMORY_PRIVATE nodes on systems
without cpusets, so private-node zones can leak into allocation
paths that should only see general-purpose memory.
Add numa_zon... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:18 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | N_MEMORY fallback lists should not include N_MEMORY_PRIVATE nodes, at
worst this would allow allocation from them in some scenarios, and at
best it causes iterations over nodes that aren't eligible.
Private node primary fallback lists do include N_MEMORY nodes so
kernel/slab allocations made on behalf of the private n... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:19 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Multiple mm/ subsystems already skip operations for ZONE_DEVICE folios,
and N_MEMORY_PRIVATE folios share the checkpoints for ZONE_DEVICE pages.
Add folio_is_private_managed() as a unified predicate that returns true
for folios on N_MEMORY_PRIVATE nodes or in ZONE_DEVICE.
This predicate replaces folio_is_zone_device ... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:20 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node folios are managed by device drivers and should not be
mlocked. The existing folio_is_zone_device check is already correctly
placed to handle this - simply extend it for private nodes.
Signed-off-by: Gregory Price <gourry@gourry.net>
---
mm/mlock.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:21 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node folios are managed by device drivers and should not be
subjectto madvise cold/pageout/free operations that would interfere
with the driver's memory management.
Extend the existing zone_device check to cover private nodes.
Signed-off-by: Gregory Price <gourry@gourry.net>
---
mm/madvise.c | 5 +++--
1 fil... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:22 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node folios should not participate in KSM merging by default.
The driver manages the memory lifecycle and KSM's page sharing can
interfere with driver operations.
Extend the existing zone_device checks in get_mergeable_page and
ksm_next_page_pmd_entry to cover private node folios as well.
Signed-off-by: Grego... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:23 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | A collapse operation allocates a new large folio and migrates the
smaller folios into it. This is an issue for private nodes:
1. The private node service may not support migration
2. Collapse may promotes pages from the private node to a local node,
which may result in an LRU inversion that defeats memory ti... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:24 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | When a folio's refcount drops to zero, the service may need to perform
cleanup before the page returns to the buddy allocator (e.g. zeroing
pages to scrub stale compressed data / release compression ratio).
Add folio_managed_on_free() to wrap both zone_device and private node
semantics for this operation since they ar... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:25 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Some private node services may need to update internal metadata when
a THP folio is split. ZONE_DEVICE already has a split callback via
pgmap->ops; private nodes can provide the same capability.
Just like zone_device, some private node services may want to know
about a folio being split. Add this optional callback t... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:26 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node services may want to support user-driven migration
(migrate_pages syscall, mbind) to allow data movement between regular
and private nodes.
ZONE_DEVICE always rejects user migration, but private nodes should
be able to opt in.
Add NP_OPS_MIGRATION flag and folio_managed_user_migrate() wrapper that
dispat... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:27 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Some private nodes want userland to directly allocate from the node
via set_mempolicy() and mbind() - but don't want that node as normal
allocable system memory in the fallback lists.
Add NP_OPS_MEMPOLICY flag requiring NP_OPS_MIGRATION (since mbind can
drive migrations). Only allow private nodes in policy nodemasks ... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:28 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | The memory-tier subsystem needs to know which private nodes should
appear as demotion targets.
Add NP_OPS_DEMOTION (BIT(2)):
Node can be added as a demotion target by memory-tiers.
Add demotion backpressure support so private nodes can reject
new demotions cleanly, allowing vmscan to fall back to swap.
In the dem... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:29 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Services that intercept write faults (e.g., for promotion tracking)
need PTEs to stay read-only. This requires preventing mprotect
from silently upgrade the PTE, bypassing the service's handle_fault
callback.
Add NP_OPS_PROTECT_WRITE and folio_managed_wrprotect().
In change_pte_range() and change_huge_pmd(), suppress... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:30 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node services that drive kswapd via watermark_boost need
control over the reclaim policy. There are three problems:
1) Boosted reclaim suppresses may_swap and may_writepage. When
demotion is not possible, swap is the only evict path, so kswapd
cannot make progress and pages are stranded.
2) __setup_pe... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:31 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | The OOM killer must know whether killing a task can actually free
memory such that pressure is reduced.
A private node only contributes to relieving pressure if it participates
in both reclaim and demotion. Without this check, the check, the OOM
killer may select an undeserving victim.
Introduce NP_OPS_OOM_ELIGIBLE a... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:32 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Not all private nodes may wish to engage in NUMA balancing faults.
Add the NP_OPS_NUMA_BALANCING flag (BIT(5)) as an opt-in method.
Introduce folio_managed_allows_numa() helper:
ZONE_DEVICE folios always return false (never NUMA-scanned)
NP_OPS_NUMA_BALANCING filters for private nodes
In do_numa_page(), if a p... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:33 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node zones should not be compacted unless the service explicitly
opts in - as compaction requires migration and services may have
PFN-based metadata that needs updating.
Add a folio_migrate callback which fires from migrate_folio_move() for
each relocated folio before faults are unblocked.
Add zone_supports_c... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:34 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Private node folios should not be longterm-pinnable by default.
A pinned folio is frozen in place, no migration, compaction, or
reclaim, so the service loses control for the duration of the pin.
Some services may depend on hot-unplugability and must disallow
longterm pinning. Others (accelerators with shared CPU-devi... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:35 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add a void memory_failure notification callback to struct
node_private_ops so services managing N_MEMORY_PRIVATE nodes notified
when a page on their node experiences a hardware error.
The callback is notification only -- the kernel always proceeds with
standard hwpoison handling for online pages.
The notification hoo... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:36 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add a new function for drivers to hotplug memory as N_MEMORY_PRIVATE.
This function combines node_private_region_register() with
__add_memory_driver_managed() to ensure proper ordering:
1. Register the private region first (sets private node context)
2. Then hotplug the memory (sets N_MEMORY_PRIVATE)
3. On failure, u... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:37 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add the CRAM (Compressed RAM) subsystem that manages folios demoted
to N_MEMORY_PRIVATE nodes via the standard kernel LRU.
We limit entry into CRAM by demotion in to provide devices a way for
drivers to close access - which allows the system to stabiliz under
memory pressure (the device can run out of real memory when... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:38 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add the CXL sysram region for direct memory hotplug of CXL RAM regions.
This region eliminates the intermediate dax_region/dax device layer by
directly performing memory hotplug operations.
Key features:
- Supports memory tier integration for proper NUMA placement
- Uses the CXL_SYSRAM_ONLINE_* Kconfig options for de... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:39 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Extend the cxl_sysram region to support N_MEMORY_PRIVATE hotplug
via add_private_memory_driver_managed(). When a caller passes
private=true to devm_cxl_add_sysram(), the memory is registered
as a private node, isolating it from normal allocations and reclaim.
Signed-off-by: Gregory Price <gourry@gourry.net>
---
drive... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:40 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add a sample CXL type-3 driver that registers device memory as
private-node NUMA memory reachable only via explicit mempolicy
(set_mempolicy / mbind).
Probe flow:
1. Call cxl_pci_type3_probe_init() for standard CXL device setup
2. Look for pre-committed RAM regions; if none exist, create one
using cxl_get_hpa... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:41 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | Add a generic CXL type-3 driver for compressed memory controllers.
The driver provides an alternative PCI binding that converts CXL
RAM regions to private-node sysram and registers them with the
CRAM subsystem for transparent demotion/promotion.
Probe flow:
1. cxl_pci_type3_probe_init() for standard CXL device setu... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Sun, 22 Feb 2026 03:48:42 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On 2/22/26 09:48, Gregory Price wrote:
I'm concerned about adding more special-casing (similar to what we
already added for ZONE_DEVICE) all over the place.
Like the whole folio_managed_() stuff in mprotect.c
Having that said, sounds like a reasonable topic to discuss.
--
Cheers,
David | {
"author": "\"David Hildenbrand (Arm)\" <david@kernel.org>",
"date": "Mon, 23 Feb 2026 14:07:15 +0100",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Mon, Feb 23, 2026 at 02:07:15PM +0100, David Hildenbrand (Arm) wrote:
It's a valid concern - and is why I tried to re-use as many of the
zone_device hooks as possible. It does not seem zone_device has quite
the same semantics for a case like this, so I had to make something new.
DEVICE_COHERENT injects a temporar... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Mon, 23 Feb 2026 09:54:55 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Mon, Feb 23, 2026 at 09:54:55AM -0500, Gregory Price wrote:
scratch all this - existing hooks exist for exactly this purpose:
can_change_[pte|pmd]_writable()
Surprised I missed this.
I can clean this up to remove it from the page table walks.
Still valid to question whether we want this, but at least the hook
... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Mon, 23 Feb 2026 11:08:38 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On 2026-02-22 at 19:48 +1100, Gregory Price <gourry@gourry.net> wrote...
Having had to re-implement entire portions of mm/ in a driver I agree this isn't
something anyone sane should do :-) However aspects of ZONE_DEVICE were added
precisely to help with that so I'm not sure N_MEMORY_PRIVATE is the only or best
way to... | {
"author": "Alistair Popple <apopple@nvidia.com>",
"date": "Tue, 24 Feb 2026 17:19:11 +1100",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Tue, Feb 24, 2026 at 05:19:11PM +1100, Alistair Popple wrote:
I agree that buddy-access alone is insufficient justification, it
started off that way - but if you want mempolicy/NUMA UAPI access,
it turns into "Re-use all of MM" - and that means using the buddy.
I also expected ZONE_DEVICE vs NODE_DATA to be the pr... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Tue, 24 Feb 2026 10:17:38 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Tue, Feb 24, 2026 at 10:17:38AM -0500, Gregory Price wrote:
This gave me something to chew on
I think this can be done without introducing N_MEMORY_PRIVATE and just
checking: NODE_DATA(target_nid)->private
meaning these nodes can just be N_MEMORY with the same isolations.
I'll look at this a bit more.
~Gregor... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Tue, 24 Feb 2026 11:54:52 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On 2/22/26 08:48, Gregory Price wrote:
Hi Gregory,
I can see the nid param is just a "preferred nid" with alloc pages.
Using __GFP_PRIVATE will restrict the allocation to private nodes but I
think the idea here is:
1) I own this node
2) Do not give me memory from another private node but from mine.
Should no... | {
"author": "Alejandro Lucero Palau <alucerop@amd.com>",
"date": "Wed, 25 Feb 2026 12:40:09 +0000",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Wed, Feb 25, 2026 at 12:40:09PM +0000, Alejandro Lucero Palau wrote:
A right I set up GFP_PRIVATE for this
#define GFP_PRIVATE (__GFP_PRIVATE | __GFP_THISNODE)
If your service hides the interface to get to this node behind something
it controls, and it doesn't enable things like reclaim/compaction etc,
then i... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Wed, 25 Feb 2026 09:43:27 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Tue, Feb 24, 2026 at 10:17:38AM -0500, Gregory Price wrote:
I was about to chime in with essentially the same comment about DRM.
Switching over to core-managed MM is a massive shift and is likely
infeasible, or so extreme that we’d end up throwing away any the
existing driver and starting from scratch. At least for... | {
"author": "Matthew Brost <matthew.brost@intel.com>",
"date": "Wed, 25 Feb 2026 14:21:54 -0800",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Wed, Feb 25, 2026 at 02:21:54PM -0800, Matthew Brost wrote:
I also think the usage patterns don't quite match (today).
GPUs seem to care very much about specific size allocations, contiguity,
how users get swapped in/out, how reclaim occurs, specific shutdown
procedures - etc.
A private node service just wants to... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Wed, 25 Feb 2026 18:58:21 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On 2026-02-25 at 02:17 +1100, Gregory Price <gourry@gourry.net> wrote...
I think you have this around the wrong way - DEVICE_PRIVATE is the odd one out as
it is the one ZONE_DEVICE page type that uses softleaf entries and doesn't
allow direct mappings. Every other type of ZONE_DEVICE page allows for direct
mappings.
... | {
"author": "Alistair Popple <apopple@nvidia.com>",
"date": "Thu, 26 Feb 2026 14:27:24 +1100",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Thu, Feb 26, 2026 at 02:27:24PM +1100, Alistair Popple wrote:
Sorry, you are correct. I have trouble keeping the ZONE_DEVICE modes
straight sometimes, and all the hook sites have different reasons for why
all the different ZONE_DEVICE modes and it mucks with my head :[
Device Coherent is the one that doesn't allo... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Thu, 26 Feb 2026 00:54:08 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Topic type: MM
Presenter: Gregory Price <gourry@gourry.net>
This series introduces N_MEMORY_PRIVATE, a NUMA node state for memory
managed by the buddy allocator but excluded from normal allocations.
I present it with an end-to-end Compressed RAM service (mm/cram.c)
that would otherwise not be possible (or would be c... | null | null | null | [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) | On Thu, Feb 26, 2026 at 12:54:08AM -0500, Gregory Price wrote:
Out of curiosity i went digging through existing users, and it seems
like the average driver has 1-8 discrete pgmaps, with Nouveau being an
outliar that does ad-hoc registering in 256MB chunks, with the relevant
annoyance being the percpu_ref it uses to tr... | {
"author": "Gregory Price <gourry@gourry.net>",
"date": "Thu, 26 Feb 2026 17:49:14 -0500",
"is_openbsd": false,
"thread_id": "aaDN6ocubzGUz6zc@gourry-fedora-PF4VCD3F.mbox.gz"
} |
lkml_critique | linux-mm | Recently, I have been actively contributing to the swap subsystem through
works such as swap-tier patches and flash friendly swap proposal. During this
process, I have consistently reviewed swap table code, some other patches and fixed several
bugs.
As I am already CC'd on many patches and maintaining active interest ... | null | null | null | [PATCH] MAINTAINERS: Add myself as reviewer for SWAP | On Thu, Feb 26, 2026 at 9:08 AM Youngjun Park <youngjun.park@lge.com> wrote:
This is very welcome.
Reviewed-by: Barry Song <baohua@kernel.org>
Best Regards
Barry | {
"author": "Barry Song <21cnbao@gmail.com>",
"date": "Thu, 26 Feb 2026 13:22:26 +0800",
"is_openbsd": false,
"thread_id": "aaDxHGasv2zGTwIn@MiWiFi-R3L-srv.mbox.gz"
} |
lkml_critique | linux-mm | Recently, I have been actively contributing to the swap subsystem through
works such as swap-tier patches and flash friendly swap proposal. During this
process, I have consistently reviewed swap table code, some other patches and fixed several
bugs.
As I am already CC'd on many patches and maintaining active interest ... | null | null | null | [PATCH] MAINTAINERS: Add myself as reviewer for SWAP | On Thu, Feb 26, 2026 at 9:09 AM Youngjun Park <youngjun.park@lge.com> wrote:
Youngjun has been very helpful on reviewing recent swap patches and
changes, and contributed a lot with fixes and ideas like tiering and
other proposals. I'm glad to have Youngjun help watching the swap
code!
Acked-by: Kairui Song <kasong@te... | {
"author": "Kairui Song <ryncsn@gmail.com>",
"date": "Thu, 26 Feb 2026 13:51:04 +0800",
"is_openbsd": false,
"thread_id": "aaDxHGasv2zGTwIn@MiWiFi-R3L-srv.mbox.gz"
} |
lkml_critique | linux-mm | Recently, I have been actively contributing to the swap subsystem through
works such as swap-tier patches and flash friendly swap proposal. During this
process, I have consistently reviewed swap table code, some other patches and fixed several
bugs.
As I am already CC'd on many patches and maintaining active interest ... | null | null | null | [PATCH] MAINTAINERS: Add myself as reviewer for SWAP | Hi Youngjun,
Welcome and thanks for your contributions. Looking forward to more
collaboration with you.
On Wed, Feb 25, 2026 at 5:08 PM Youngjun Park <youngjun.park@lge.com> wrote:
Acked-by: Chris Li <chrisl@kernel.org>
Chris | {
"author": "Chris Li <chrisl@kernel.org>",
"date": "Thu, 26 Feb 2026 11:57:16 -0800",
"is_openbsd": false,
"thread_id": "aaDxHGasv2zGTwIn@MiWiFi-R3L-srv.mbox.gz"
} |
lkml_critique | linux-mm | Recently, I have been actively contributing to the swap subsystem through
works such as swap-tier patches and flash friendly swap proposal. During this
process, I have consistently reviewed swap table code, some other patches and fixed several
bugs.
As I am already CC'd on many patches and maintaining active interest ... | null | null | null | [PATCH] MAINTAINERS: Add myself as reviewer for SWAP | On 02/26/26 at 10:07am, Youngjun Park wrote:
Ack these and welcome.
Acked-by: Baoquan He <bhe@redhat.com> | {
"author": "Baoquan He <bhe@redhat.com>",
"date": "Fri, 27 Feb 2026 09:19:24 +0800",
"is_openbsd": false,
"thread_id": "aaDxHGasv2zGTwIn@MiWiFi-R3L-srv.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | Currently split cannot fail, but future patches will add lazy PTE page
table allocation. With lazy PTE page table allocation at THP split time
__split_huge_pmd() calls pte_alloc_one() which can fail if order-0
allocation cannot be satisfied.
Split functions currently return void, so callers have no way to detect
this f... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:30 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | With lazy PTE page table allocation, split_huge_pmd_if_needed() and
thus vma_adjust_trans_huge() can now fail if order-0 allocation
for pagetable fails when trying to split. It is important to check
if this failure occurred to prevent a huge PMD straddling at VMA
boundary.
The vma_adjust_trans_huge() call is moved bef... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:31 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | copy_huge_pmd() splits the source PMD when a folio is pinned and can't
be COW-shared at PMD granularity. It then returns -EAGAIN so
copy_pmd_range() falls through to copy_pte_range().
If the split fails, the PMD is still huge. Returning -EAGAIN would cause
copy_pmd_range() to call copy_pte_range(), which would deref... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:32 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | do_huge_pmd_wp_page() splits the PMD when a COW of the entire huge page
fails (e.g., can't allocate a new folio or the folio is pinned). It then
returns VM_FAULT_FALLBACK so the fault can be retried at PTE granularity.
If the split fails, the PMD is still huge. Returning VM_FAULT_FALLBACK
would re-enter the PTE faul... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:33 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | zap_pmd_range() splits a huge PMD when the zap range doesn't cover the
full PMD (partial unmap). If the split fails, the PMD stays huge.
Falling through to zap_pte_range() would dereference the huge PMD entry
as a PTE page table pointer.
Skip the range covered by the PMD on split failure instead.
The skip is safe ac... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:34 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | wp_huge_pmd() splits the PMD when COW or write-notify must be handled at
PTE level (e.g., shared/file VMAs, userfaultfd). It then returns
VM_FAULT_FALLBACK so the fault handler retries at PTE granularity.
If the split fails, the PMD is still huge. The PTE fault path cannot
handle a huge PMD entry.
Return VM_FAULT_OOM... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:35 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | change_pmd_range() splits a huge PMD when mprotect() targets a sub-PMD
range or when VMA flags require per-PTE protection bits that can't be
represented at PMD granularity.
If pte_alloc_one() fails inside __split_huge_pmd(), the huge PMD remains
intact. Without this change, change_pte_range() would return -EAGAIN
beca... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:36 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | follow_pmd_mask() splits a huge PMD when FOLL_SPLIT_PMD is set, so GUP
can pin individual pages at PTE granularity.
If the split fails, the PMD is still huge and follow_page_pte() cannot
process it. Return ERR_PTR(-ENOMEM) on split failure, which causes the
GUP caller to get -ENOMEM. -ENOMEM is already returned in fol... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:37 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | walk_pmd_range() splits a huge PMD when a page table walker with
pte_entry or install_pte callbacks needs PTE-level granularity. If
the split fails due to memory allocation failure in pte_alloc_one(),
walk_pte_range() would encounter a huge PMD instead of a PTE page
table.
Break out of the loop on split failure and re... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:38 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
lkml_critique | linux-mm | When the kernel creates a PMD-level THP mapping for anonymous pages, it
pre-allocates a PTE page table via pgtable_trans_huge_deposit(). This
page table sits unused in a deposit list for the lifetime of the THP
mapping, only to be withdrawn when the PMD is split or zapped. Every
anonymous THP therefore wastes 4KB of me... | null | null | null | [RFC v2 00/21] mm: thp: lazy PTE page table allocation at PMD split | move_page_tables() splits a huge PMD when the extent is smaller than
HPAGE_PMD_SIZE and the PMD can't be moved at PMD granularity.
If the split fails, the PMD stays huge and move_ptes() can't operate on
individual PTEs.
Break out of the loop on split failure, which causes mremap() to return
however much was moved so ... | {
"author": "Usama Arif <usama.arif@linux.dev>",
"date": "Thu, 26 Feb 2026 03:23:39 -0800",
"is_openbsd": false,
"thread_id": "4672053f-c9d9-4694-81ad-9b5fe741013a@linux.dev.mbox.gz"
} |
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