From: David Hildenbrand <david@redhat.com>
To: Lance Yang <ioworker0@gmail.com>
Cc: ziy@nvidia.com, 21cnbao@gmail.com, akpm@linux-foundation.org,
fengwei.yin@intel.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, maskray@google.com, mhocko@suse.com,
minchan@kernel.org, peterx@redhat.com, ryan.roberts@arm.com,
shy828301@gmail.com, songmuchun@bytedance.com,
wangkefeng.wang@huawei.com, willy@infradead.org,
xiehuan09@gmail.com, zokeefe@google.com
Subject: Re: [PATCH v2 1/1] mm/vmscan: avoid split PMD-mapped THP during shrink_folio_list()
Date: Thu, 25 Apr 2024 11:25:11 +0200 [thread overview]
Message-ID: <e75b509a-bf4f-418c-a921-cf3383fc5929@redhat.com> (raw)
In-Reply-To: <CAK1f24kaphS9Gz4Nxe-+=iHs_+CpA1Qk7q=pdzUJKc5u-0_qXw@mail.gmail.com>
>> I was wondering if we can better integrate that into the pagewalk below.
>>
>> That is, don't do the TTU_SPLIT_HUGE_PMD immediately. Start the pagewalk
>> first. If we walk a PMD, try to unmap it. Only if that fails, split it.
>
> Nice. Thanks for the suggestion!
> I'll work on integrating it into the pagewalk as you suggested.
>
>>
>> Less working on "vma + address" and instead directly on PMDs.
>
> Yes, some of the work on "vma + address" can be avoided :)
Doing the conditional split while in the pagewalk will be the
interesting bit to sort out (we temporarily have to drop the PTL and
start once again from that now-PTE-mapped page table). But it should be
a reasonable thing to have.
Please let us know if you run into bigger issues with that!
See walk_pmd_range() as an inspiration where we call split_huge_pmd().
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-04-25 9:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-22 5:52 [PATCH v2 1/1] mm/vmscan: avoid split PMD-mapped THP during shrink_folio_list() Lance Yang
2024-04-24 4:15 ` Matthew Wilcox
2024-04-24 7:17 ` David Hildenbrand
2024-04-24 15:57 ` Zi Yan
2024-04-24 15:58 ` David Hildenbrand
2024-04-25 4:17 ` Lance Yang
2024-04-25 8:50 ` Lance Yang
2024-04-25 9:01 ` David Hildenbrand
2024-04-25 9:21 ` Lance Yang
2024-04-25 9:25 ` David Hildenbrand [this message]
2024-04-25 12:00 ` Lance Yang
2024-04-24 15:46 ` Lance Yang
2024-04-24 21:20 ` Andrew Morton
2024-04-25 4:19 ` Lance Yang
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