From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Lance Yang <ioworker0@gmail.com>, akpm@linux-foundation.org
Cc: willy@infradead.org, sj@kernel.org, maskray@google.com,
ziy@nvidia.com, ryan.roberts@arm.com, david@redhat.com,
21cnbao@gmail.com, mhocko@suse.com, fengwei.yin@intel.com,
zokeefe@google.com, shy828301@gmail.com, xiehuan09@gmail.com,
libang.li@antgroup.com, wangkefeng.wang@huawei.com,
songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND v5 3/4] mm/mlock: check for THP missing the mlock in try_to_unmap_one()
Date: Tue, 14 May 2024 14:41:27 +0800 [thread overview]
Message-ID: <f22c9fc8-2356-46c6-ac8e-dc97328d7fcc@linux.alibaba.com> (raw)
In-Reply-To: <20240513074712.7608-4-ioworker0@gmail.com>
On 2024/5/13 15:47, Lance Yang wrote:
> The TTU_SPLIT_HUGE_PMD will no longer perform immediately, so we might
> encounter a PMD-mapped THP missing the mlock in the VM_LOCKED range
> during the pagewalk. It's likely necessary to mlock this THP to prevent
> it from being picked up during page reclaim.
>
> Suggested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Signed-off-by: Lance Yang <ioworker0@gmail.com>
IMO, this patch should be merged into patch 2, otherwise patch 2 is
buggy. Quote the description in the 'submission patches.rst' document:
"When dividing your change into a series of patches, take special care
to ensure that the kernel builds and runs properly after each patch in
the series. Developers using ``git bisect`` to track down a problem can
end up splitting your patch series at any point; they will not thank you
if you introduce bugs in the middle."
> ---
> mm/rmap.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 4c4d14325f2e..08a93347f283 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1671,7 +1671,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> if (!(flags & TTU_IGNORE_MLOCK) &&
> (vma->vm_flags & VM_LOCKED)) {
> /* Restore the mlock which got missed */
> - if (!folio_test_large(folio))
> + if (!folio_test_large(folio) ||
> + (!pvmw.pte && (flags & TTU_SPLIT_HUGE_PMD)))
> mlock_vma_folio(folio, vma);
> goto walk_done_err;
> }
next prev parent reply other threads:[~2024-05-14 6:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 7:47 [PATCH RESEND v5 0/4] Reclaim lazyfree THP without splitting Lance Yang
2024-05-13 7:47 ` [PATCH RESEND v5 1/4] mm/rmap: remove duplicated exit code in pagewalk loop Lance Yang
2024-05-14 6:26 ` Baolin Wang
2024-05-14 7:43 ` Lance Yang
2024-05-13 7:47 ` [PATCH RESEND v5 2/4] mm/rmap: integrate PMD-mapped folio splitting into " Lance Yang
2024-05-13 7:47 ` [PATCH RESEND v5 3/4] mm/mlock: check for THP missing the mlock in try_to_unmap_one() Lance Yang
2024-05-14 6:41 ` Baolin Wang [this message]
2024-05-14 7:46 ` Lance Yang
2024-05-13 7:47 ` [PATCH RESEND v5 4/4] mm/vmscan: avoid split lazyfree THP during shrink_folio_list() Lance Yang
2024-05-14 7:09 ` Baolin Wang
2024-05-14 8:36 ` Lance Yang
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