From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org,
willy@infradead.org, linux-btrfs@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 03/16] mm: add PG_uncached page flag
Date: Tue, 12 Nov 2024 11:12:15 +0200 [thread overview]
Message-ID: <lponnb7dxjx3htksbggjoasvby6sa2a4ayrkcykdnxvypwy4pp@ci2fnmcyrke7> (raw)
In-Reply-To: <20241111234842.2024180-4-axboe@kernel.dk>
On Mon, Nov 11, 2024 at 04:37:30PM -0700, Jens Axboe wrote:
> Add a page flag that file IO can use to indicate that the IO being done
> is uncached, as in it should not persist in the page cache after the IO
> has been completed.
I have not found a way to avoid using a new bit. I am unsure if we have
enough bits on 32-bit systems with all possible features enabled.
In the worst-case scenario, we may need to make the feature 64-bit only.
I believe it should be acceptable as long as userspace is prepared for the
possibility that RWF_UNCACHED may fail. It is not going to be supported by
all filesystems anyway.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2024-11-12 9:12 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-11 23:37 [PATCHSET v3 0/16] Uncached buffered IO Jens Axboe
2024-11-11 23:37 ` [PATCH 01/16] mm/filemap: change filemap_create_folio() to take a struct kiocb Jens Axboe
2024-11-11 23:37 ` [PATCH 02/16] mm/readahead: add folio allocation helper Jens Axboe
2024-11-11 23:37 ` [PATCH 03/16] mm: add PG_uncached page flag Jens Axboe
2024-11-12 9:12 ` Kirill A. Shutemov [this message]
2024-11-12 14:07 ` Jens Axboe
2024-11-11 23:37 ` [PATCH 04/16] mm/readahead: add readahead_control->uncached member Jens Axboe
2024-11-11 23:37 ` [PATCH 05/16] mm/filemap: use page_cache_sync_ra() to kick off read-ahead Jens Axboe
2024-11-11 23:37 ` [PATCH 06/16] mm/truncate: add folio_unmap_invalidate() helper Jens Axboe
2024-11-11 23:37 ` [PATCH 07/16] fs: add RWF_UNCACHED iocb and FOP_UNCACHED file_operations flag Jens Axboe
2024-11-11 23:37 ` [PATCH 08/16] mm/filemap: add read support for RWF_UNCACHED Jens Axboe
2024-11-11 23:37 ` [PATCH 09/16] mm/filemap: drop uncached pages when writeback completes Jens Axboe
2024-11-12 9:31 ` Kirill A. Shutemov
2024-11-12 14:09 ` Jens Axboe
2024-11-11 23:37 ` [PATCH 10/16] mm/filemap: make buffered writes work with RWF_UNCACHED Jens Axboe
2024-11-12 0:57 ` Dave Chinner
2024-11-12 1:27 ` Jens Axboe
2024-11-12 8:02 ` Dave Chinner
2024-11-12 9:50 ` Kirill A. Shutemov
2024-11-12 13:36 ` Dave Chinner
2024-11-12 14:51 ` Jens Axboe
2024-11-11 23:37 ` [PATCH 11/16] mm: add FGP_UNCACHED folio creation flag Jens Axboe
2024-11-11 23:37 ` [PATCH 12/16] ext4: add RWF_UNCACHED write support Jens Axboe
2024-11-12 16:36 ` Brian Foster
2024-11-12 17:13 ` Jens Axboe
2024-11-12 18:11 ` Brian Foster
2024-11-12 18:47 ` Jens Axboe
2024-11-11 23:37 ` [PATCH 13/16] iomap: make buffered writes work with RWF_UNCACHED Jens Axboe
2024-11-12 1:01 ` Darrick J. Wong
2024-11-12 1:30 ` Jens Axboe
2024-11-12 16:37 ` Brian Foster
2024-11-12 17:16 ` Jens Axboe
2024-11-12 18:15 ` Brian Foster
2024-11-11 23:37 ` [PATCH 14/16] xfs: punt uncached write completions to the completion wq Jens Axboe
2024-11-11 23:37 ` [PATCH 15/16] xfs: flag as supporting FOP_UNCACHED Jens Axboe
2024-11-11 23:37 ` [PATCH 16/16] btrfs: add support for uncached writes Jens Axboe
2024-11-12 1:31 ` [PATCHSET v3 0/16] Uncached buffered IO Jens Axboe
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