| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <94c8899a-f116-4b6a-94d3-f8295ee3f535@linux.alibaba.com>
Date: Fri, 18 Jul 2025 13:04:54 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Nico Pache <npache@...hat.com>, linux-mm@...ck.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org
Cc: david@...hat.com, ziy@...dia.com, lorenzo.stoakes@...cle.com,
Liam.Howlett@...cle.com, ryan.roberts@....com, dev.jain@....com,
corbet@....net, rostedt@...dmis.org, mhiramat@...nel.org,
mathieu.desnoyers@...icios.com, akpm@...ux-foundation.org,
baohua@...nel.org, willy@...radead.org, peterx@...hat.com,
wangkefeng.wang@...wei.com, usamaarif642@...il.com, sunnanyong@...wei.com,
vishal.moola@...il.com, thomas.hellstrom@...ux.intel.com,
yang@...amperecomputing.com, kirill.shutemov@...ux.intel.com,
aarcange@...hat.com, raquini@...hat.com, anshuman.khandual@....com,
catalin.marinas@....com, tiwai@...e.de, will@...nel.org,
dave.hansen@...ux.intel.com, jack@...e.cz, cl@...two.org,
jglisse@...gle.com, surenb@...gle.com, zokeefe@...gle.com,
hannes@...xchg.org, rientjes@...gle.com, mhocko@...e.com,
rdunlap@...radead.org, hughd@...gle.com
Subject: Re: [PATCH v9 13/14] khugepaged: add per-order mTHP khugepaged stats
On 2025/7/14 08:32, Nico Pache wrote:
> With mTHP support inplace, let add the per-order mTHP stats for
> exceeding NONE, SWAP, and SHARED.
>
> Signed-off-by: Nico Pache <npache@...hat.com>
> ---
> Documentation/admin-guide/mm/transhuge.rst | 17 +++++++++++++++++
> include/linux/huge_mm.h | 3 +++
> mm/huge_memory.c | 7 +++++++
> mm/khugepaged.c | 15 ++++++++++++---
> 4 files changed, 39 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
> index 2c523dce6bc7..28c8af61efba 100644
> --- a/Documentation/admin-guide/mm/transhuge.rst
> +++ b/Documentation/admin-guide/mm/transhuge.rst
> @@ -658,6 +658,23 @@ nr_anon_partially_mapped
> an anonymous THP as "partially mapped" and count it here, even though it
> is not actually partially mapped anymore.
>
> +collapse_exceed_swap_pte
> + The number of anonymous THP which contain at least one swap PTE.
> + Currently khugepaged does not support collapsing mTHP regions that
> + contain a swap PTE.
> +
> +collapse_exceed_none_pte
> + The number of anonymous THP which have exceeded the none PTE threshold.
> + With mTHP collapse, a bitmap is used to gather the state of a PMD region
> + and is then recursively checked from largest to smallest order against
> + the scaled max_ptes_none count. This counter indicates that the next
> + enabled order will be checked.
> +
> +collapse_exceed_shared_pte
> + The number of anonymous THP which contain at least one shared PTE.
> + Currently khugepaged does not support collapsing mTHP regions that
> + contain a shared PTE.
> +
> As the system ages, allocating huge pages may be expensive as the
> system uses memory compaction to copy data around memory to free a
> huge page for use. There are some counters in ``/proc/vmstat`` to help
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 4042078e8cc9..e0a27f80f390 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -141,6 +141,9 @@ enum mthp_stat_item {
> MTHP_STAT_SPLIT_DEFERRED,
> MTHP_STAT_NR_ANON,
> MTHP_STAT_NR_ANON_PARTIALLY_MAPPED,
> + MTHP_STAT_COLLAPSE_EXCEED_SWAP,
> + MTHP_STAT_COLLAPSE_EXCEED_NONE,
> + MTHP_STAT_COLLAPSE_EXCEED_SHARED,
> __MTHP_STAT_COUNT
> };
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index e2ed9493df77..57e5699cf638 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -632,6 +632,10 @@ DEFINE_MTHP_STAT_ATTR(split_failed, MTHP_STAT_SPLIT_FAILED);
> DEFINE_MTHP_STAT_ATTR(split_deferred, MTHP_STAT_SPLIT_DEFERRED);
> DEFINE_MTHP_STAT_ATTR(nr_anon, MTHP_STAT_NR_ANON);
> DEFINE_MTHP_STAT_ATTR(nr_anon_partially_mapped, MTHP_STAT_NR_ANON_PARTIALLY_MAPPED);
> +DEFINE_MTHP_STAT_ATTR(collapse_exceed_swap_pte, MTHP_STAT_COLLAPSE_EXCEED_SWAP);
> +DEFINE_MTHP_STAT_ATTR(collapse_exceed_none_pte, MTHP_STAT_COLLAPSE_EXCEED_NONE);
> +DEFINE_MTHP_STAT_ATTR(collapse_exceed_shared_pte, MTHP_STAT_COLLAPSE_EXCEED_SHARED);
> +
>
> static struct attribute *anon_stats_attrs[] = {
> &anon_fault_alloc_attr.attr,
> @@ -648,6 +652,9 @@ static struct attribute *anon_stats_attrs[] = {
> &split_deferred_attr.attr,
> &nr_anon_attr.attr,
> &nr_anon_partially_mapped_attr.attr,
> + &collapse_exceed_swap_pte_attr.attr,
> + &collapse_exceed_none_pte_attr.attr,
> + &collapse_exceed_shared_pte_attr.attr,
> NULL,
> };
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index d0c99b86b304..8a5873d0a23a 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -594,7 +594,10 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
> continue;
> } else {
> result = SCAN_EXCEED_NONE_PTE;
> - count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
> + if (order == HPAGE_PMD_ORDER)
> + count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
> + else
> + count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_NONE);
Please follow the same logic as other mTHP statistics, meaning there is
no need to filter out PMD-sized orders, because mTHP also supports
PMD-sized orders. So logic should be:
if (order == HPAGE_PMD_ORDER)
count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_NONE);
> goto out;
> }
> }
> @@ -623,8 +626,14 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
> /* See khugepaged_scan_pmd(). */
> if (folio_maybe_mapped_shared(folio)) {
> ++shared;
> - if (order != HPAGE_PMD_ORDER || (cc->is_khugepaged &&
> - shared > khugepaged_max_ptes_shared)) {
> + if (order != HPAGE_PMD_ORDER) {
> + result = SCAN_EXCEED_SHARED_PTE;
> + count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_SHARED);
> + goto out;
> + }
Ditto.
> +
> + if (cc->is_khugepaged &&
> + shared > khugepaged_max_ptes_shared) {
> result = SCAN_EXCEED_SHARED_PTE;
> count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
> goto out;
Powered by blists - more mailing lists