Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2024-12-28 16:52:18 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

memcg/hugetlb: introduce memcg_accounts_hugetlb

Browse Source 
Patch series "memcg/hugetlb: Rework memcg hugetlb charging", v3.

This series cleans up memcg's hugetlb charging logic by deprecating the
current memcg hugetlb try-charge + {commit, cancel} logic present in
alloc_hugetlb_folio.  A single function mem_cgroup_charge_hugetlb takes
its place instead.  This makes the code more maintainable by simplifying
the error path and reduces memcg's footprint in hugetlb logic.

This patch introduces a few changes in the hugetlb folio allocation
error path:
(a) Instead of having multiple return points, we consolidate them to
    two: one for reaching the memcg limit or running out of memory
    (-ENOMEM) and one for hugetlb allocation fails / limit being
    reached (-ENOSPC).
(b) Previously, the memcg limit was checked before the folio is acquired,
    meaning the hugeTLB folio isn't acquired if the limit is reached.
    This patch performs the charging after the folio is reached, meaning
    if memcg's limit is reached, the acquired folio is freed right away.

This patch builds on two earlier patch series: [2] which adds memcg
hugeTLB counters, and [3] which deprecates charge moving and removes the
last references to mem_cgroup_cancel_charge.  The request for this cleanup
can be found in [2].

[1] https://lore.kernel.org/all/20231006184629.155543-1-nphamcs@gmail.com/
[2] https://lore.kernel.org/all/20241101204402.1885383-1-joshua.hahnjy@gmail.com/
[3] https://lore.kernel.org/linux-mm/20241025012304.2473312-1-shakeel.butt@linux.dev/


This patch (of 3):

This patch isolates the check for whether memcg accounts hugetlb.  This
condition can only be true if the memcg mount option
memory_hugetlb_accounting is on, which includes hugetlb usage in
memory.current.

Link: https://lkml.kernel.org/r/20241211203951.764733-1-joshua.hahnjy@gmail.com
Link: https://lkml.kernel.org/r/20241211203951.764733-2-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Joshua Hahn 2024-12-11 12:39:49 -08:00 committed by Andrew Morton
parent b126895586
commit fbd3462b74
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
mm/memcontrol.c
View File

@ -1448,6 +1448,18 @@ unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item)
memcg_page_state_output_unit(item);
}
#ifdef CONFIG_HUGETLB_PAGE
static bool memcg_accounts_hugetlb(void)
{
return cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING;
}
#else /* CONFIG_HUGETLB_PAGE */
static bool memcg_accounts_hugetlb(void)
{
return false;
}
#endif /* CONFIG_HUGETLB_PAGE */
static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
{
int i;
@ -1469,7 +1481,7 @@ static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
#ifdef CONFIG_HUGETLB_PAGE
if (unlikely(memory_stats[i].idx == NR_HUGETLB) &&
!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING))
!memcg_accounts_hugetlb())
continue;
#endif
size = memcg_page_state_output(memcg, memory_stats[i].idx);
@ -4540,8 +4552,7 @@ int mem_cgroup_hugetlb_try_charge(struct mem_cgroup *memcg, gfp_t gfp,
* but do not attempt to commit charge later (or cancel on error) either.
*/
if (mem_cgroup_disabled() || !memcg ||
!cgroup_subsys_on_dfl(memory_cgrp_subsys) ||
!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING))
!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !memcg_accounts_hugetlb())
return -EOPNOTSUPP;
if (try_charge(memcg, gfp, nr_pages))