From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Chandan Babu R <chandan.babu@oracle.com>,
"Darrick J. Wong" <djwong@kernel.org>,
Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-xfs@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 07/21] shmem: document how to "persist" data when using shmem_*file_setup
Date: Fri, 26 Jan 2024 15:49:30 +0000 [thread overview]
Message-ID: <ZbPUilScedGAm8g_@casper.infradead.org> (raw)
In-Reply-To: <20240126132903.2700077-8-hch@lst.de>
On Fri, Jan 26, 2024 at 02:28:49PM +0100, Christoph Hellwig wrote:
> +++ b/mm/shmem.c
> @@ -2150,6 +2150,11 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> *
> * Return: The found folio, %NULL if SGP_READ or SGP_NOALLOC was passed in @sgp
> * and no folio was found at @index, or an ERR_PTR() otherwise.
> + *
> + * If the caller modifies data in the returned folio, it must call
> + * folio_mark_dirty() on the locked folio before dropping the reference to
> + * ensure the folio is not reclaimed. Unlike for normal file systems there is
> + * no need to reserve space for users of shmem_*file_setup().
This doesn't quite make sense to me. Do you mean:
* If the caller modifies data in the folio, it must call folio_mark_dirty()
* before unlocking the folio to ensure that the folio is not reclaimed.
* There is no equivalent to write_begin/write_end for shmem.
(also this should go before the Return: section; the return section
should be the last thing in the kernel-doc)
next prev parent reply other threads:[~2024-01-26 15:49 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-26 13:28 put the xfs xfile abstraction on a diet v2 Christoph Hellwig
2024-01-26 13:28 ` [PATCH 01/21] mm: move mapping_set_update out of <linux/swap.h> Christoph Hellwig
2024-01-26 14:39 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 02/21] shmem: move shmem_mapping out of line Christoph Hellwig
2024-01-26 14:40 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 03/21] shmem: set a_ops earlier in shmem_symlink Christoph Hellwig
2024-01-26 14:41 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 04/21] shmem: move the shmem_mapping assert into shmem_get_folio_gfp Christoph Hellwig
2024-01-26 15:09 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 05/21] shmem: export shmem_get_folio Christoph Hellwig
2024-01-26 15:15 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 06/21] shmem: export shmem_kernel_file_setup Christoph Hellwig
2024-01-26 15:45 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 07/21] shmem: document how to "persist" data when using shmem_*file_setup Christoph Hellwig
2024-01-26 15:49 ` Matthew Wilcox [this message]
2024-01-28 16:54 ` Christoph Hellwig
2024-01-29 15:56 ` Matthew Wilcox
2024-01-29 16:04 ` Christoph Hellwig
2024-01-26 13:28 ` [PATCH 08/21] xfs: remove xfile_stat Christoph Hellwig
2024-01-26 13:28 ` [PATCH 09/21] xfs: remove the xfile_pread/pwrite APIs Christoph Hellwig
2024-01-26 16:21 ` Matthew Wilcox
2024-01-26 16:48 ` Darrick J. Wong
2024-01-26 13:28 ` [PATCH 10/21] xfs: don't try to handle non-update pages in xfile_obj_load Christoph Hellwig
2024-01-26 13:28 ` [PATCH 11/21] xfs: shmem_file_setup can't return NULL Christoph Hellwig
2024-01-26 13:28 ` [PATCH 12/21] xfs: don't modify file and inode flags for shmem files Christoph Hellwig
2024-01-26 13:28 ` [PATCH 13/21] xfs: don't allow highmem pages in xfile mappings Christoph Hellwig
2024-01-26 16:26 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 14/21] xfs: use shmem_get_folio in xfile_obj_store Christoph Hellwig
2024-01-26 16:29 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 15/21] xfs: use shmem_get_folio in in xfile_load Christoph Hellwig
2024-01-26 13:28 ` [PATCH 16/21] xfs: improve detection of lost xfile contents Christoph Hellwig
2024-01-26 16:33 ` Matthew Wilcox
2024-01-26 16:50 ` Darrick J. Wong
2024-01-28 16:55 ` Christoph Hellwig
2024-01-28 20:33 ` Matthew Wilcox
2024-01-26 13:28 ` [PATCH 17/21] xfs: add file_{get,put}_folio Christoph Hellwig
2024-01-26 16:40 ` Matthew Wilcox
2024-01-26 16:55 ` Darrick J. Wong
2024-01-27 1:26 ` Kent Overstreet
2024-01-27 1:32 ` Darrick J. Wong
2024-01-26 13:29 ` [PATCH 18/21] xfs: remove xfarray_sortinfo.page_kaddr Christoph Hellwig
2024-01-26 13:29 ` [PATCH 19/21] xfs: fix a comment in xfarray.c Christoph Hellwig
2024-01-26 13:29 ` [PATCH 20/21] xfs: convert xfarray_pagesort to deal with large folios Christoph Hellwig
2024-01-27 1:09 ` Kent Overstreet
2024-01-26 13:29 ` [PATCH 21/21] xfs: remove xfile_{get,put}_page Christoph Hellwig
2024-01-26 14:15 ` put the xfs xfile abstraction on a diet v2 Matthew Wilcox
2024-01-26 14:18 ` Christoph Hellwig
2024-01-26 16:47 ` Matthew Wilcox
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