From: Matthew Wilcox <willy@infradead.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
David Hildenbrand <david@redhat.com>,
Gregory Price <gregory.price@memverge.com>
Subject: Re: [PATCH v2 1/7] fs/proc/page: remove unneeded PageTail && PageSlab check
Date: Fri, 10 Nov 2023 18:11:16 +0000 [thread overview]
Message-ID: <ZU5yROwNmTZpyxb8@casper.infradead.org> (raw)
In-Reply-To: <20231110033324.2455523-2-wangkefeng.wang@huawei.com>
On Fri, Nov 10, 2023 at 11:33:18AM +0800, Kefeng Wang wrote:
> After commit dcb351cd095a ("page-flags: define behavior SL*B-related
> flags on compound pages"), the slab could not be a tail, remove unneeded
> PageTail && PageSlab check.
No, that's completely wrong.
* PF_NO_TAIL:
* modifications of the page flag must be done on small or head pages,
* checks can be done on tail pages too.
That's backed up by the code:
#define PF_NO_TAIL(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
PF_POISONED_CHECK(compound_head(page)); })
(enforce is set to 0 for the 'test')
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
NAK
next prev parent reply other threads:[~2023-11-10 18:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-10 3:33 [PATCH v2 0/7] mm: remove page idle and young wrapper Kefeng Wang
2023-11-10 3:33 ` [PATCH v2 1/7] fs/proc/page: remove unneeded PageTail && PageSlab check Kefeng Wang
2023-11-10 18:11 ` Matthew Wilcox [this message]
2023-11-10 3:33 ` [PATCH v2 2/7] fs/proc/page: use a folio in stable_page_flags() Kefeng Wang
2023-11-10 18:15 ` Matthew Wilcox
2023-11-11 3:21 ` Kefeng Wang
2023-11-10 21:50 ` Gregory Price
2023-11-10 3:33 ` [PATCH v2 3/7] fs/proc/page: respect folio head-page flag placement Kefeng Wang
2023-11-10 18:19 ` Matthew Wilcox
2023-11-11 9:49 ` Kefeng Wang
2023-11-10 3:33 ` [PATCH v2 4/7] mm: huge_memory: use more folio api in __split_huge_page_tail() Kefeng Wang
2023-11-10 18:20 ` Matthew Wilcox
2023-11-11 10:00 ` Kefeng Wang
2023-11-10 3:33 ` [PATCH v2 5/7] mm: task_mmu: use a folio in smaps_account() Kefeng Wang
2023-11-10 18:29 ` Matthew Wilcox
2023-11-11 10:57 ` Kefeng Wang
2023-11-10 3:33 ` [PATCH v2 6/7] mm: task_mmu: use a folio in clear_refs_pte_range() Kefeng Wang
2023-11-10 3:33 ` [PATCH v2 7/7] page_idle: kill page idle and young wrapper Kefeng Wang
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