From: Linus Torvalds <torvalds@linux-foundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Android Kernel Team <kernel-team@android.com>,
Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Vinayak Menon <vinmenon@codeaurora.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/2] mm: Allow architectures to request 'old' entries when prefaulting
Date: Wed, 9 Dec 2020 13:04:22 -0800 [thread overview]
Message-ID: <CAHk-=wjCk9frb1Y+pkzh-vXGdvbs5=B=2NanG6yGLY35s99wBg@mail.gmail.com> (raw)
In-Reply-To: <20201209203203.GU7338@casper.infradead.org>
On Wed, Dec 9, 2020 at 12:32 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> If a filesystem has put an Uptodate page into the page cache, the
> rest of the kernel can read it without telling the filesystem.
XFS does the same thing for xfs_file_read_iter() too.
Not that I disagree with you - when you mmap a file, once it's mapped
you see the data without any lock anyway. So it's all kinds of
pointless to serialize the page fault, because that's simply not
relevant. The lock will be gone by the time the user actually sees the
data.
But hey, the XFS people have their opinions.
Linus
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next prev parent reply other threads:[~2020-12-09 21:05 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 16:39 [PATCH 0/2] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2020-12-09 16:39 ` [PATCH 1/2] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2020-12-09 17:58 ` Linus Torvalds
2020-12-09 18:40 ` Will Deacon
2020-12-09 19:04 ` Linus Torvalds
2020-12-09 20:32 ` Matthew Wilcox
2020-12-09 21:04 ` Linus Torvalds [this message]
2020-12-10 15:08 ` Kirill A. Shutemov
2020-12-10 17:23 ` Linus Torvalds
2020-12-14 16:07 ` Kirill A. Shutemov
2020-12-14 17:54 ` Linus Torvalds
2020-12-14 18:56 ` Matthew Wilcox
2020-12-16 17:07 ` Kirill A. Shutemov
2020-12-16 18:41 ` Linus Torvalds
2020-12-17 10:54 ` Kirill A. Shutemov
2020-12-17 18:22 ` Linus Torvalds
2020-12-18 11:04 ` Kirill A. Shutemov
2020-12-18 18:56 ` Linus Torvalds
2020-12-19 12:41 ` Kirill A. Shutemov
2020-12-19 20:08 ` Linus Torvalds
2020-12-19 20:34 ` Linus Torvalds
2020-12-22 10:00 ` Kirill A. Shutemov
2020-12-24 4:04 ` Hugh Dickins
2020-12-25 11:31 ` Kirill A. Shutemov
2020-12-26 17:57 ` Linus Torvalds
2020-12-26 20:43 ` Kirill A. Shutemov
2020-12-26 21:03 ` Hugh Dickins
2020-12-26 21:16 ` Linus Torvalds
2020-12-26 22:40 ` Kirill A. Shutemov
2020-12-27 0:45 ` Hugh Dickins
2020-12-27 2:38 ` Hugh Dickins
2020-12-27 19:38 ` Linus Torvalds
2020-12-27 20:32 ` Damian Tometzki
2020-12-27 22:35 ` Hugh Dickins
2020-12-27 23:12 ` Linus Torvalds
2020-12-27 23:40 ` Linus Torvalds
2020-12-27 23:55 ` Kirill A. Shutemov
2020-12-27 23:48 ` Kirill A. Shutemov
2020-12-28 1:54 ` Linus Torvalds
2020-12-28 6:43 ` Hugh Dickins
2020-12-28 12:53 ` Kirill A. Shutemov
2020-12-28 18:47 ` Linus Torvalds
2020-12-28 21:58 ` Linus Torvalds
2020-12-29 13:28 ` Kirill A. Shutemov
2020-12-29 15:19 ` Matthew Wilcox
2020-12-29 20:52 ` Linus Torvalds
2020-12-28 22:05 ` Kirill A. Shutemov
2020-12-28 22:12 ` Kirill A. Shutemov
2020-12-29 4:35 ` Hugh Dickins
2020-12-28 23:28 ` Linus Torvalds
2020-12-26 21:07 ` Linus Torvalds
2020-12-26 21:41 ` Matthew Wilcox
2020-12-09 16:39 ` [PATCH 2/2] arm64: mm: Implement arch_wants_old_faultaround_pte() Will Deacon
2020-12-09 18:35 ` Catalin Marinas
2020-12-09 18:46 ` Will Deacon
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