From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org,
willy@infradead.org, kirill@shutemov.name, bfoster@redhat.com
Subject: Re: [PATCH 07/12] fs: add RWF_UNCACHED iocb and FOP_UNCACHED file_operations flag
Date: Thu, 12 Dec 2024 12:42:56 -0700 [thread overview]
Message-ID: <47a26818-8f15-4189-8d53-0fb11bdcb03e@kernel.dk> (raw)
In-Reply-To: <Z1gkg68w-G9151cC@infradead.org>
On 12/10/24 4:22 AM, Christoph Hellwig wrote:
> On Tue, Dec 03, 2024 at 08:31:43AM -0700, Jens Axboe wrote:
>> + if (flags & RWF_UNCACHED) {
>> + /* file system must support it */
>> + if (!(ki->ki_filp->f_op->fop_flags & FOP_UNCACHED))
>> + return -EOPNOTSUPP;
>> + /* DAX mappings not supported */
>> + if (IS_DAX(ki->ki_filp->f_mapping->host))
>> + return -EOPNOTSUPP;
>
> I'd argue that DAX is always uncached and could just ignore the flag.
> Same for direct I/O.
It's more of a safe guard in terms of the invalidation requiring extra
work for DAX.
--
Jens Axboe
next prev parent reply other threads:[~2024-12-12 19:43 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-03 15:31 [PATCHSET v6 0/12] Uncached buffered IO Jens Axboe
2024-12-03 15:31 ` [PATCH 01/12] mm/filemap: change filemap_create_folio() to take a struct kiocb Jens Axboe
2024-12-10 11:13 ` Christoph Hellwig
2024-12-12 15:49 ` Jens Axboe
2024-12-03 15:31 ` [PATCH 02/12] mm/readahead: add folio allocation helper Jens Axboe
2024-12-03 15:31 ` [PATCH 03/12] mm: add PG_uncached page flag Jens Axboe
2024-12-03 15:31 ` [PATCH 04/12] mm/readahead: add readahead_control->uncached member Jens Axboe
2024-12-03 15:31 ` [PATCH 05/12] mm/filemap: use page_cache_sync_ra() to kick off read-ahead Jens Axboe
2024-12-10 11:15 ` Christoph Hellwig
2024-12-03 15:31 ` [PATCH 06/12] mm/truncate: add folio_unmap_invalidate() helper Jens Axboe
2024-12-10 11:21 ` Christoph Hellwig
2024-12-12 20:19 ` Jens Axboe
2024-12-03 15:31 ` [PATCH 07/12] fs: add RWF_UNCACHED iocb and FOP_UNCACHED file_operations flag Jens Axboe
2024-12-06 17:35 ` Darrick J. Wong
2024-12-10 11:22 ` Christoph Hellwig
2024-12-12 19:42 ` Jens Axboe [this message]
2024-12-03 15:31 ` [PATCH 08/12] mm/filemap: add read support for RWF_UNCACHED Jens Axboe
2024-12-03 15:31 ` [PATCH 09/12] mm/filemap: drop uncached pages when writeback completes Jens Axboe
2024-12-03 15:31 ` [PATCH 10/12] mm/filemap: add filemap_fdatawrite_range_kick() helper Jens Axboe
2024-12-03 15:31 ` [PATCH 11/12] mm/filemap: make buffered writes work with RWF_UNCACHED Jens Axboe
2024-12-06 17:17 ` Darrick J. Wong
2024-12-06 18:22 ` Jens Axboe
2024-12-10 11:31 ` Christoph Hellwig
2024-12-12 15:51 ` Jens Axboe
2024-12-03 15:31 ` [PATCH 12/12] mm: add FGP_UNCACHED folio creation flag Jens Axboe
2024-12-03 18:23 ` [PATCHSET v6 0/12] Uncached buffered IO Christoph Lameter (Ampere)
2024-12-03 21:06 ` Jens Axboe
2024-12-03 22:16 ` Christoph Lameter (Ampere)
2024-12-03 22:41 ` Jens Axboe
2024-12-04 5:52 ` Darrick J. Wong
2024-12-04 16:36 ` Jens Axboe
2024-12-10 11:11 ` Christoph Hellwig
2024-12-12 15:48 ` Jens Axboe
2024-12-12 16:59 ` Christoph Lameter (Ampere)
2024-12-12 19:14 ` Jens Axboe
2024-12-12 19:35 ` Matthew Wilcox
2024-12-12 19:36 ` Jens Axboe
2024-12-12 20:06 ` Christoph Lameter (Ampere)
2024-12-13 5:04 ` Johannes Weiner
2024-12-13 14:49 ` Jens Axboe
2024-12-06 17:37 ` Darrick J. Wong
2024-12-10 9:48 ` Bharata B Rao
2024-12-12 15:46 ` Jens Axboe
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