* [PATCHSET 0/2] Add XFS support for RWF_DONTCACHE @ 2025-02-03 16:32 Jens Axboe 2025-02-03 16:32 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 2025-02-03 16:32 ` [PATCH 2/2] xfs: flag as supporting FOP_DONTCACHE Jens Axboe 0 siblings, 2 replies; 14+ messages in thread From: Jens Axboe @ 2025-02-03 16:32 UTC (permalink / raw) To: cem, djwong; +Cc: linux-xfs Hi, Now that the main bits are in mainline, here are the XFS patches for adding RWF_DONTCACHE support. It's pretty trivial - patch 1 adds the basic iomap flag and check, and patch 2 flags FOP_DONTCACHE support in the file_operations struct. Could be folded into a single patch at this point, I'll leave that up to you guys what you prefer. Patches are aginst 6.14-rc1. -- Jens Axboe ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-03 16:32 [PATCHSET 0/2] Add XFS support for RWF_DONTCACHE Jens Axboe @ 2025-02-03 16:32 ` Jens Axboe 2025-02-03 17:19 ` Darrick J. Wong 2025-02-03 16:32 ` [PATCH 2/2] xfs: flag as supporting FOP_DONTCACHE Jens Axboe 1 sibling, 1 reply; 14+ messages in thread From: Jens Axboe @ 2025-02-03 16:32 UTC (permalink / raw) To: cem, djwong; +Cc: linux-xfs, Jens Axboe Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is set for a write, mark the folios being written as uncached. Then writeback completion will drop the pages. The write_iter handler simply kicks off writeback for the pages, and writeback completion will take care of the rest. This still needs the user of the iomap buffered write helpers to call folio_end_dropbehind_write() upon successful issue of the writes. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/iomap/buffered-io.c | 4 ++++ include/linux/iomap.h | 1 + 2 files changed, 5 insertions(+) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index d303e6c8900c..ea863c3cf510 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) if (iter->flags & IOMAP_NOWAIT) fgp |= FGP_NOWAIT; + if (iter->flags & IOMAP_DONTCACHE) + fgp |= FGP_DONTCACHE; fgp |= fgf_set_order(len); return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; + if (iocb->ki_flags & IOCB_DONTCACHE) + iter.flags |= IOMAP_DONTCACHE; while ((ret = iomap_iter(&iter, ops)) > 0) iter.processed = iomap_write_iter(&iter, i); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 75bf54e76f3b..26b0dbe23e62 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -183,6 +183,7 @@ struct iomap_folio_ops { #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ #define IOMAP_ATOMIC (1 << 9) +#define IOMAP_DONTCACHE (1 << 10) struct iomap_ops { /* -- 2.47.2 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-03 16:32 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe @ 2025-02-03 17:19 ` Darrick J. Wong 2025-02-03 18:26 ` Jens Axboe 0 siblings, 1 reply; 14+ messages in thread From: Darrick J. Wong @ 2025-02-03 17:19 UTC (permalink / raw) To: Jens Axboe; +Cc: cem, linux-xfs On Mon, Feb 03, 2025 at 09:32:38AM -0700, Jens Axboe wrote: > Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is > set for a write, mark the folios being written as uncached. Then > writeback completion will drop the pages. The write_iter handler simply > kicks off writeback for the pages, and writeback completion will take > care of the rest. > > This still needs the user of the iomap buffered write helpers to call > folio_end_dropbehind_write() upon successful issue of the writes. I thought iomap calls folio_end_writeback, which cares of that? So xfs doesn't itself have to call folio_end_dropbehind_write? > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > fs/iomap/buffered-io.c | 4 ++++ > include/linux/iomap.h | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index d303e6c8900c..ea863c3cf510 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) > > if (iter->flags & IOMAP_NOWAIT) > fgp |= FGP_NOWAIT; > + if (iter->flags & IOMAP_DONTCACHE) > + fgp |= FGP_DONTCACHE; > fgp |= fgf_set_order(len); > > return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, > @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, > > if (iocb->ki_flags & IOCB_NOWAIT) > iter.flags |= IOMAP_NOWAIT; > + if (iocb->ki_flags & IOCB_DONTCACHE) > + iter.flags |= IOMAP_DONTCACHE; > > while ((ret = iomap_iter(&iter, ops)) > 0) > iter.processed = iomap_write_iter(&iter, i); > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 75bf54e76f3b..26b0dbe23e62 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -183,6 +183,7 @@ struct iomap_folio_ops { > #define IOMAP_DAX 0 > #endif /* CONFIG_FS_DAX */ > #define IOMAP_ATOMIC (1 << 9) > +#define IOMAP_DONTCACHE (1 << 10) This needs a mention in the iomap documentation. If the patch below accurately summarizes what it does nowadays, then you can add it to the series with a: Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> --D diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst index b0d0188a095e55..7b91546750f59e 100644 --- a/Documentation/filesystems/iomap/design.rst +++ b/Documentation/filesystems/iomap/design.rst @@ -352,6 +352,11 @@ operations: ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or ``RWF_NOWAIT``. + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a + buffered file I/O and would like the kernel to drop the pagecache + after the I/O completes, if it isn't already being used by another + thread. + If it is necessary to read existing file contents from a `different <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ device or address range on a device, the filesystem should return that diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 2c7f5df9d8b037..584ff549f9a659 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. + Internal per-Folio State ------------------------ ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-03 17:19 ` Darrick J. Wong @ 2025-02-03 18:26 ` Jens Axboe 0 siblings, 0 replies; 14+ messages in thread From: Jens Axboe @ 2025-02-03 18:26 UTC (permalink / raw) To: Darrick J. Wong; +Cc: cem, linux-xfs On 2/3/25 10:19 AM, Darrick J. Wong wrote: > On Mon, Feb 03, 2025 at 09:32:38AM -0700, Jens Axboe wrote: >> Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is >> set for a write, mark the folios being written as uncached. Then >> writeback completion will drop the pages. The write_iter handler simply >> kicks off writeback for the pages, and writeback completion will take >> care of the rest. >> >> This still needs the user of the iomap buffered write helpers to call >> folio_end_dropbehind_write() upon successful issue of the writes. > > I thought iomap calls folio_end_writeback, which cares of that? So xfs > doesn't itself have to call folio_end_dropbehind_write? Yep it does, stale commit message! I'll fix it up and send out a v2. >> fs/iomap/buffered-io.c | 4 ++++ >> include/linux/iomap.h | 1 + >> 2 files changed, 5 insertions(+) >> >> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c >> index d303e6c8900c..ea863c3cf510 100644 >> --- a/fs/iomap/buffered-io.c >> +++ b/fs/iomap/buffered-io.c >> @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) >> >> if (iter->flags & IOMAP_NOWAIT) >> fgp |= FGP_NOWAIT; >> + if (iter->flags & IOMAP_DONTCACHE) >> + fgp |= FGP_DONTCACHE; >> fgp |= fgf_set_order(len); >> >> return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, >> @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, >> >> if (iocb->ki_flags & IOCB_NOWAIT) >> iter.flags |= IOMAP_NOWAIT; >> + if (iocb->ki_flags & IOCB_DONTCACHE) >> + iter.flags |= IOMAP_DONTCACHE; >> >> while ((ret = iomap_iter(&iter, ops)) > 0) >> iter.processed = iomap_write_iter(&iter, i); >> diff --git a/include/linux/iomap.h b/include/linux/iomap.h >> index 75bf54e76f3b..26b0dbe23e62 100644 >> --- a/include/linux/iomap.h >> +++ b/include/linux/iomap.h >> @@ -183,6 +183,7 @@ struct iomap_folio_ops { >> #define IOMAP_DAX 0 >> #endif /* CONFIG_FS_DAX */ >> #define IOMAP_ATOMIC (1 << 9) >> +#define IOMAP_DONTCACHE (1 << 10) > > This needs a mention in the iomap documentation. If the patch below > accurately summarizes what it does nowadays, then you can add it to the > series with a: Thanks Darrick, I'll add that and your SOB as well. -- Jens Axboe ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH 2/2] xfs: flag as supporting FOP_DONTCACHE 2025-02-03 16:32 [PATCHSET 0/2] Add XFS support for RWF_DONTCACHE Jens Axboe 2025-02-03 16:32 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe @ 2025-02-03 16:32 ` Jens Axboe 1 sibling, 0 replies; 14+ messages in thread From: Jens Axboe @ 2025-02-03 16:32 UTC (permalink / raw) To: cem, djwong; +Cc: linux-xfs, Jens Axboe Read side was already fully supported, and with the write side appropriately punted to the worker queue, all that's needed now is setting FOP_DONTCACHE in the file_operations structure to enable full support for read and write uncached IO. This provides similar benefits to using RWF_DONTCACHE with reads. Testing buffered writes on 32 files: writing bs 65536, uncached 0 1s: 196035MB/sec 2s: 132308MB/sec 3s: 132438MB/sec 4s: 116528MB/sec 5s: 103898MB/sec 6s: 108893MB/sec 7s: 99678MB/sec 8s: 106545MB/sec 9s: 106826MB/sec 10s: 101544MB/sec 11s: 111044MB/sec 12s: 124257MB/sec 13s: 116031MB/sec 14s: 114540MB/sec 15s: 115011MB/sec 16s: 115260MB/sec 17s: 116068MB/sec 18s: 116096MB/sec where it's quite obvious where the page cache filled, and performance dropped from to about half of where it started, settling in at around 115GB/sec. Meanwhile, 32 kswapds were running full steam trying to reclaim pages. Running the same test with uncached buffered writes: writing bs 65536, uncached 1 1s: 198974MB/sec 2s: 189618MB/sec 3s: 193601MB/sec 4s: 188582MB/sec 5s: 193487MB/sec 6s: 188341MB/sec 7s: 194325MB/sec 8s: 188114MB/sec 9s: 192740MB/sec 10s: 189206MB/sec 11s: 193442MB/sec 12s: 189659MB/sec 13s: 191732MB/sec 14s: 190701MB/sec 15s: 191789MB/sec 16s: 191259MB/sec 17s: 190613MB/sec 18s: 191951MB/sec and the behavior is fully predictable, performing the same throughout even after the page cache would otherwise have fully filled with dirty data. It's also about 65% faster, and using half the CPU of the system compared to the normal buffered write. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/xfs/xfs_file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index f7a7d89c345e..358987b6e2f8 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1626,7 +1626,8 @@ const struct file_operations xfs_file_operations = { .fadvise = xfs_file_fadvise, .remap_file_range = xfs_file_remap_range, .fop_flags = FOP_MMAP_SYNC | FOP_BUFFER_RASYNC | - FOP_BUFFER_WASYNC | FOP_DIO_PARALLEL_WRITE, + FOP_BUFFER_WASYNC | FOP_DIO_PARALLEL_WRITE | + FOP_DONTCACHE, }; const struct file_operations xfs_dir_file_operations = { -- 2.47.2 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCHSET v2 0/2] Add XFS support for RWF_DONTCACHE @ 2025-02-04 18:39 Jens Axboe 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 0 siblings, 1 reply; 14+ messages in thread From: Jens Axboe @ 2025-02-04 18:39 UTC (permalink / raw) To: cem, djwong; +Cc: linux-xfs Hi, Now that the main bits are in mainline, here are the XFS patches for adding RWF_DONTCACHE support. It's pretty trivial - patch 1 adds the basic iomap flag and check, and patch 2 flags FOP_DONTCACHE support in the file_operations struct. Could be folded into a single patch at this point, I'll leave that up to you guys what you prefer. Patches are aginst 6.14-rc1. Since v1: - Remove stale commit message paragraph - Add comments for iomap flag from Darrick -- Jens Axboe ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-04 18:39 [PATCHSET v2 0/2] Add XFS support for RWF_DONTCACHE Jens Axboe @ 2025-02-04 18:39 ` Jens Axboe 2025-02-20 6:06 ` Christoph Hellwig ` (3 more replies) 0 siblings, 4 replies; 14+ messages in thread From: Jens Axboe @ 2025-02-04 18:39 UTC (permalink / raw) To: cem, djwong; +Cc: linux-xfs, Jens Axboe Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is set for a write, mark the folios being written as uncached. Then writeback completion will drop the pages. The write_iter handler simply kicks off writeback for the pages, and writeback completion will take care of the rest. Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> --- Documentation/filesystems/iomap/design.rst | 5 +++++ Documentation/filesystems/iomap/operations.rst | 2 ++ fs/iomap/buffered-io.c | 4 ++++ include/linux/iomap.h | 1 + 4 files changed, 12 insertions(+) diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst index b0d0188a095e..7b91546750f5 100644 --- a/Documentation/filesystems/iomap/design.rst +++ b/Documentation/filesystems/iomap/design.rst @@ -352,6 +352,11 @@ operations: ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or ``RWF_NOWAIT``. + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a + buffered file I/O and would like the kernel to drop the pagecache + after the I/O completes, if it isn't already being used by another + thread. + If it is necessary to read existing file contents from a `different <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ device or address range on a device, the filesystem should return that diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 2c7f5df9d8b0..584ff549f9a6 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. + Internal per-Folio State ------------------------ diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index d303e6c8900c..ea863c3cf510 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) if (iter->flags & IOMAP_NOWAIT) fgp |= FGP_NOWAIT; + if (iter->flags & IOMAP_DONTCACHE) + fgp |= FGP_DONTCACHE; fgp |= fgf_set_order(len); return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; + if (iocb->ki_flags & IOCB_DONTCACHE) + iter.flags |= IOMAP_DONTCACHE; while ((ret = iomap_iter(&iter, ops)) > 0) iter.processed = iomap_write_iter(&iter, i); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 75bf54e76f3b..26b0dbe23e62 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -183,6 +183,7 @@ struct iomap_folio_ops { #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ #define IOMAP_ATOMIC (1 << 9) +#define IOMAP_DONTCACHE (1 << 10) struct iomap_ops { /* -- 2.47.2 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe @ 2025-02-20 6:06 ` Christoph Hellwig 2025-02-27 9:51 ` Carlos Maiolino ` (2 subsequent siblings) 3 siblings, 0 replies; 14+ messages in thread From: Christoph Hellwig @ 2025-02-20 6:06 UTC (permalink / raw) To: Jens Axboe; +Cc: cem, djwong, linux-xfs Looks good: Reviewed-by: Christoph Hellwig <hch@lst.de> ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 2025-02-20 6:06 ` Christoph Hellwig @ 2025-02-27 9:51 ` Carlos Maiolino 2025-02-27 10:30 ` Christian Brauner 2025-03-03 13:07 ` John Garry 2025-03-12 20:40 ` Chaitanya Kulkarni 3 siblings, 1 reply; 14+ messages in thread From: Carlos Maiolino @ 2025-02-27 9:51 UTC (permalink / raw) To: brauner; +Cc: djwong, linux-xfs, axboe On Tue, Feb 04, 2025 at 11:39:59AM -0700, Jens Axboe wrote: > Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is > set for a write, mark the folios being written as uncached. Then > writeback completion will drop the pages. The write_iter handler simply > kicks off writeback for the pages, and writeback completion will take > care of the rest. > [Adding Brauner to the loop as this usually goes through his tree.] Christian, I'm pulling this into my tree for 6.15 if this is ok with you? Not sure if you're subscribed to linux-xfs, so, just in case, the link for the whole 2-patches series is below. https://lore.kernel.org/linux-xfs/20250204184047.356762-1-axboe@kernel.dk/ > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > Documentation/filesystems/iomap/design.rst | 5 +++++ > Documentation/filesystems/iomap/operations.rst | 2 ++ > fs/iomap/buffered-io.c | 4 ++++ > include/linux/iomap.h | 1 + > 4 files changed, 12 insertions(+) > > diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst > index b0d0188a095e..7b91546750f5 100644 > --- a/Documentation/filesystems/iomap/design.rst > +++ b/Documentation/filesystems/iomap/design.rst > @@ -352,6 +352,11 @@ operations: > ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or > ``RWF_NOWAIT``. > > + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a > + buffered file I/O and would like the kernel to drop the pagecache > + after the I/O completes, if it isn't already being used by another > + thread. > + > If it is necessary to read existing file contents from a `different > <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ > device or address range on a device, the filesystem should return that > diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst > index 2c7f5df9d8b0..584ff549f9a6 100644 > --- a/Documentation/filesystems/iomap/operations.rst > +++ b/Documentation/filesystems/iomap/operations.rst > @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: > > * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. > > + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. > + > Internal per-Folio State > ------------------------ > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index d303e6c8900c..ea863c3cf510 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) > > if (iter->flags & IOMAP_NOWAIT) > fgp |= FGP_NOWAIT; > + if (iter->flags & IOMAP_DONTCACHE) > + fgp |= FGP_DONTCACHE; > fgp |= fgf_set_order(len); > > return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, > @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, > > if (iocb->ki_flags & IOCB_NOWAIT) > iter.flags |= IOMAP_NOWAIT; > + if (iocb->ki_flags & IOCB_DONTCACHE) > + iter.flags |= IOMAP_DONTCACHE; > > while ((ret = iomap_iter(&iter, ops)) > 0) > iter.processed = iomap_write_iter(&iter, i); > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 75bf54e76f3b..26b0dbe23e62 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -183,6 +183,7 @@ struct iomap_folio_ops { > #define IOMAP_DAX 0 > #endif /* CONFIG_FS_DAX */ > #define IOMAP_ATOMIC (1 << 9) > +#define IOMAP_DONTCACHE (1 << 10) > > struct iomap_ops { > /* > -- > 2.47.2 > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-27 9:51 ` Carlos Maiolino @ 2025-02-27 10:30 ` Christian Brauner 2025-02-27 10:57 ` Carlos Maiolino 2025-02-27 15:14 ` Christoph Hellwig 0 siblings, 2 replies; 14+ messages in thread From: Christian Brauner @ 2025-02-27 10:30 UTC (permalink / raw) To: Carlos Maiolino; +Cc: djwong, linux-xfs, axboe On Thu, Feb 27, 2025 at 10:51:40AM +0100, Carlos Maiolino wrote: > On Tue, Feb 04, 2025 at 11:39:59AM -0700, Jens Axboe wrote: > > Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is > > set for a write, mark the folios being written as uncached. Then > > writeback completion will drop the pages. The write_iter handler simply > > kicks off writeback for the pages, and writeback completion will take > > care of the rest. > > > > [Adding Brauner to the loop as this usually goes through his tree.] > > Christian, I'm pulling this into my tree for 6.15 if this is ok with you? > Not sure if you're subscribed to linux-xfs, so, just in case, the link for the > whole 2-patches series is below. > > https://lore.kernel.org/linux-xfs/20250204184047.356762-1-axboe@kernel.dk/ vfs-6.15.iomap has a lot of iomap changes already so we should use a shared tree we can both merge. I've put this on: vfs-6.15.shared.iomap Just pull it into your branch, please and I pull it into vfs-6.15.iomap. I see that 2/2 adds a new FOP_UNCACHED flag to the VFS FOP_UNCACHED please make sure to Cc fsdevel for such additions and remind contributors as well. > > > > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> > > Signed-off-by: Jens Axboe <axboe@kernel.dk> > > --- > > Documentation/filesystems/iomap/design.rst | 5 +++++ > > Documentation/filesystems/iomap/operations.rst | 2 ++ > > fs/iomap/buffered-io.c | 4 ++++ > > include/linux/iomap.h | 1 + > > 4 files changed, 12 insertions(+) > > > > diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst > > index b0d0188a095e..7b91546750f5 100644 > > --- a/Documentation/filesystems/iomap/design.rst > > +++ b/Documentation/filesystems/iomap/design.rst > > @@ -352,6 +352,11 @@ operations: > > ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or > > ``RWF_NOWAIT``. > > > > + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a > > + buffered file I/O and would like the kernel to drop the pagecache > > + after the I/O completes, if it isn't already being used by another > > + thread. > > + > > If it is necessary to read existing file contents from a `different > > <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ > > device or address range on a device, the filesystem should return that > > diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst > > index 2c7f5df9d8b0..584ff549f9a6 100644 > > --- a/Documentation/filesystems/iomap/operations.rst > > +++ b/Documentation/filesystems/iomap/operations.rst > > @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: > > > > * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. > > > > + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. > > + > > Internal per-Folio State > > ------------------------ > > > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > index d303e6c8900c..ea863c3cf510 100644 > > --- a/fs/iomap/buffered-io.c > > +++ b/fs/iomap/buffered-io.c > > @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) > > > > if (iter->flags & IOMAP_NOWAIT) > > fgp |= FGP_NOWAIT; > > + if (iter->flags & IOMAP_DONTCACHE) > > + fgp |= FGP_DONTCACHE; > > fgp |= fgf_set_order(len); > > > > return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, > > @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, > > > > if (iocb->ki_flags & IOCB_NOWAIT) > > iter.flags |= IOMAP_NOWAIT; > > + if (iocb->ki_flags & IOCB_DONTCACHE) > > + iter.flags |= IOMAP_DONTCACHE; > > > > while ((ret = iomap_iter(&iter, ops)) > 0) > > iter.processed = iomap_write_iter(&iter, i); > > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > > index 75bf54e76f3b..26b0dbe23e62 100644 > > --- a/include/linux/iomap.h > > +++ b/include/linux/iomap.h > > @@ -183,6 +183,7 @@ struct iomap_folio_ops { > > #define IOMAP_DAX 0 > > #endif /* CONFIG_FS_DAX */ > > #define IOMAP_ATOMIC (1 << 9) > > +#define IOMAP_DONTCACHE (1 << 10) > > > > struct iomap_ops { > > /* > > -- > > 2.47.2 > > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-27 10:30 ` Christian Brauner @ 2025-02-27 10:57 ` Carlos Maiolino 2025-02-27 15:14 ` Christoph Hellwig 1 sibling, 0 replies; 14+ messages in thread From: Carlos Maiolino @ 2025-02-27 10:57 UTC (permalink / raw) To: Christian Brauner; +Cc: djwong, linux-xfs, axboe On Thu, Feb 27, 2025 at 11:30:39AM +0100, Christian Brauner wrote: > On Thu, Feb 27, 2025 at 10:51:40AM +0100, Carlos Maiolino wrote: > > On Tue, Feb 04, 2025 at 11:39:59AM -0700, Jens Axboe wrote: > > > Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is > > > set for a write, mark the folios being written as uncached. Then > > > writeback completion will drop the pages. The write_iter handler simply > > > kicks off writeback for the pages, and writeback completion will take > > > care of the rest. > > > > > > > [Adding Brauner to the loop as this usually goes through his tree.] > > > > Christian, I'm pulling this into my tree for 6.15 if this is ok with you? > > Not sure if you're subscribed to linux-xfs, so, just in case, the link for the > > whole 2-patches series is below. > > > > https://lore.kernel.org/linux-xfs/20250204184047.356762-1-axboe@kernel.dk/ > > vfs-6.15.iomap has a lot of iomap changes already so we should use a > shared tree we can both merge. I've put this on: > > vfs-6.15.shared.iomap > > Just pull it into your branch, please and I pull it into vfs-6.15.iomap. Sounds good Chris. Thanks, I'll pull it once I start merging patches for 6.15 MW. Carlos. > > I see that 2/2 adds a new FOP_UNCACHED flag to the VFS FOP_UNCACHED > please make sure to Cc fsdevel for such additions and remind > contributors as well. > > > > > > > > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org> > > > Signed-off-by: Jens Axboe <axboe@kernel.dk> > > > --- > > > Documentation/filesystems/iomap/design.rst | 5 +++++ > > > Documentation/filesystems/iomap/operations.rst | 2 ++ > > > fs/iomap/buffered-io.c | 4 ++++ > > > include/linux/iomap.h | 1 + > > > 4 files changed, 12 insertions(+) > > > > > > diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst > > > index b0d0188a095e..7b91546750f5 100644 > > > --- a/Documentation/filesystems/iomap/design.rst > > > +++ b/Documentation/filesystems/iomap/design.rst > > > @@ -352,6 +352,11 @@ operations: > > > ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or > > > ``RWF_NOWAIT``. > > > > > > + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a > > > + buffered file I/O and would like the kernel to drop the pagecache > > > + after the I/O completes, if it isn't already being used by another > > > + thread. > > > + > > > If it is necessary to read existing file contents from a `different > > > <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ > > > device or address range on a device, the filesystem should return that > > > diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst > > > index 2c7f5df9d8b0..584ff549f9a6 100644 > > > --- a/Documentation/filesystems/iomap/operations.rst > > > +++ b/Documentation/filesystems/iomap/operations.rst > > > @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: > > > > > > * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. > > > > > > + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. > > > + > > > Internal per-Folio State > > > ------------------------ > > > > > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > > index d303e6c8900c..ea863c3cf510 100644 > > > --- a/fs/iomap/buffered-io.c > > > +++ b/fs/iomap/buffered-io.c > > > @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) > > > > > > if (iter->flags & IOMAP_NOWAIT) > > > fgp |= FGP_NOWAIT; > > > + if (iter->flags & IOMAP_DONTCACHE) > > > + fgp |= FGP_DONTCACHE; > > > fgp |= fgf_set_order(len); > > > > > > return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, > > > @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, > > > > > > if (iocb->ki_flags & IOCB_NOWAIT) > > > iter.flags |= IOMAP_NOWAIT; > > > + if (iocb->ki_flags & IOCB_DONTCACHE) > > > + iter.flags |= IOMAP_DONTCACHE; > > > > > > while ((ret = iomap_iter(&iter, ops)) > 0) > > > iter.processed = iomap_write_iter(&iter, i); > > > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > > > index 75bf54e76f3b..26b0dbe23e62 100644 > > > --- a/include/linux/iomap.h > > > +++ b/include/linux/iomap.h > > > @@ -183,6 +183,7 @@ struct iomap_folio_ops { > > > #define IOMAP_DAX 0 > > > #endif /* CONFIG_FS_DAX */ > > > #define IOMAP_ATOMIC (1 << 9) > > > +#define IOMAP_DONTCACHE (1 << 10) > > > > > > struct iomap_ops { > > > /* > > > -- > > > 2.47.2 > > > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-27 10:30 ` Christian Brauner 2025-02-27 10:57 ` Carlos Maiolino @ 2025-02-27 15:14 ` Christoph Hellwig 2025-02-28 10:38 ` Christian Brauner 1 sibling, 1 reply; 14+ messages in thread From: Christoph Hellwig @ 2025-02-27 15:14 UTC (permalink / raw) To: Christian Brauner; +Cc: Carlos Maiolino, djwong, linux-xfs, axboe On Thu, Feb 27, 2025 at 11:30:39AM +0100, Christian Brauner wrote: > > https://lore.kernel.org/linux-xfs/20250204184047.356762-1-axboe@kernel.dk/ > > vfs-6.15.iomap has a lot of iomap changes already so we should use a > shared tree we can both merge. I've put this on: Note that we'll also need the earliest changes in vfs.iomap for the zoned xfs changes that are about to be ready. So we might as well pull in the entire vfs.iomap branch. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-27 15:14 ` Christoph Hellwig @ 2025-02-28 10:38 ` Christian Brauner 0 siblings, 0 replies; 14+ messages in thread From: Christian Brauner @ 2025-02-28 10:38 UTC (permalink / raw) To: Christoph Hellwig; +Cc: Carlos Maiolino, djwong, linux-xfs, axboe On Thu, Feb 27, 2025 at 07:14:43AM -0800, Christoph Hellwig wrote: > On Thu, Feb 27, 2025 at 11:30:39AM +0100, Christian Brauner wrote: > > > https://lore.kernel.org/linux-xfs/20250204184047.356762-1-axboe@kernel.dk/ > > > > vfs-6.15.iomap has a lot of iomap changes already so we should use a > > shared tree we can both merge. I've put this on: > > Note that we'll also need the earliest changes in vfs.iomap for the > zoned xfs changes that are about to be ready. So we might as well > pull in the entire vfs.iomap branch. Ok, then I'll just put the series into vfs-6.15.iomap and you can just pull that in. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 2025-02-20 6:06 ` Christoph Hellwig 2025-02-27 9:51 ` Carlos Maiolino @ 2025-03-03 13:07 ` John Garry 2025-03-12 20:40 ` Chaitanya Kulkarni 3 siblings, 0 replies; 14+ messages in thread From: John Garry @ 2025-03-03 13:07 UTC (permalink / raw) To: Jens Axboe, cem, djwong; +Cc: linux-xfs On 04/02/2025 18:39, Jens Axboe wrote: > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -183,6 +183,7 @@ struct iomap_folio_ops { > #define IOMAP_DAX 0 > #endif /* CONFIG_FS_DAX */ > #define IOMAP_ATOMIC (1 << 9) > +#define IOMAP_DONTCACHE (1 << 10) JFYI, IOMAP_FLAGS_STRINGS might need to be updated for this, but not adding it may be intentional. I did not see anyone mention this in the reviews. Thanks, John ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe ` (2 preceding siblings ...) 2025-03-03 13:07 ` John Garry @ 2025-03-12 20:40 ` Chaitanya Kulkarni 3 siblings, 0 replies; 14+ messages in thread From: Chaitanya Kulkarni @ 2025-03-12 20:40 UTC (permalink / raw) To: Jens Axboe, cem@kernel.org, djwong@kernel.org; +Cc: linux-xfs@vger.kernel.org On 2/4/25 10:39, Jens Axboe wrote: > Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is > set for a write, mark the folios being written as uncached. Then > writeback completion will drop the pages. The write_iter handler simply > kicks off writeback for the pages, and writeback completion will take > care of the rest. > > Signed-off-by: "Darrick J. Wong"<djwong@kernel.org> > Signed-off-by: Jens Axboe<axboe@kernel.dk> > --- Looks good. Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck ^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2025-03-12 20:40 UTC | newest] Thread overview: 14+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-02-03 16:32 [PATCHSET 0/2] Add XFS support for RWF_DONTCACHE Jens Axboe 2025-02-03 16:32 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 2025-02-03 17:19 ` Darrick J. Wong 2025-02-03 18:26 ` Jens Axboe 2025-02-03 16:32 ` [PATCH 2/2] xfs: flag as supporting FOP_DONTCACHE Jens Axboe -- strict thread matches above, loose matches on Subject: below -- 2025-02-04 18:39 [PATCHSET v2 0/2] Add XFS support for RWF_DONTCACHE Jens Axboe 2025-02-04 18:39 ` [PATCH 1/2] iomap: make buffered writes work with RWF_DONTCACHE Jens Axboe 2025-02-20 6:06 ` Christoph Hellwig 2025-02-27 9:51 ` Carlos Maiolino 2025-02-27 10:30 ` Christian Brauner 2025-02-27 10:57 ` Carlos Maiolino 2025-02-27 15:14 ` Christoph Hellwig 2025-02-28 10:38 ` Christian Brauner 2025-03-03 13:07 ` John Garry 2025-03-12 20:40 ` Chaitanya Kulkarni
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