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9ea8d6197d
Pull iomap updates from Christian Brauner:
"The bulk of this is the conversion of iomap to a single ->iomap_next()
callback and thus finishing the move to an iterator model.
Every iomap operation drove its iteration through a struct iomap_ops
holding ->iomap_begin() and ->iomap_end(). iomap_iter() only ever sees
those as pointers. That means every step of every iteration is an
indirect call.
This collapses both into one ->iomap_next() callback that finishes the
previous mapping and produces the next one. This lets callers inline
the iteration loop and pass its ->iomap_next() as a compile time
constant. That means the compiler can turn it into a direct and hence
inlineable call.
This also allows future callers to express custom logic to drive the
iteration forward better. xfs, btrfs, ext4, ext2, erofs, f2fs, gfs2,
hpfs, fuse, exfat, zonefs, ntfs, ntfs3 and the block device mapping
are all converted. No functional changes are intended.
This also adds a simple direct I/O path for small reads. On Gen5 NVMe
the __iomap_dio_rw() dominates 4K random reads. The same single-core
io_uring poll mode workload reaches ~3.2M IOPS against the raw block
device but only ~1.92M through ext4 or XFS.
__iomap_dio_rw(), iomap_iter(), iomap_dio_bio_iter() and kfree() were
at the top of the profile. The new path is very lightweight if no
special behavior is requested. The bio comes from a dedicated bioset
and laid out so the whole request is a single cacheline aligned
allocation. Completion runs inline.
That takes ext4 from 1.92M to 2.19M IOPS in the original workload. fio
shows around:
- 4% at libaio queue depths of 64 and up
- around 5% for io_uring
- up to 10% for io_uring poll mode at depth 256
on both ext4 and xfs.
A few other patches:
- iomap_folio_mark_uptodate() lets a filesystem that writes into the
page cache outside the iomap read and write paths keep iomap's
internal uptodate bitmap in sync, which fuse needs for
server-pushed notify stores before it can enable large folios;
- two fixes for iomap_bio_read_folio_range_sync(): a potential crash
when device integrity behavior is changed and a missing
bio_uninit().
- a folio batch release fix on iomap callback failures
- FGP_NOFS is dropped from iomap_get_folio()
- documentation fix"
* tag 'vfs-7.3-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (29 commits)
iomap: iomap_bio_read_folio_range_sync is missing a call to bio_uninit
iomap: don't free integrity payload that doesn't exist
docs: fix grammatical error in iomap docs
exfat: convert iomap ops to ->iomap_next()
fuse: convert iomap ops to ->iomap_next()
hpfs: convert iomap ops to ->iomap_next()
gfs2: convert iomap ops to ->iomap_next()
f2fs: convert iomap ops to ->iomap_next()
block: convert iomap ops to ->iomap_next()
ext2: convert iomap ops to ->iomap_next()
zonefs: convert iomap ops to ->iomap_next()
erofs: convert iomap ops to ->iomap_next()
ext4: convert iomap ops to ->iomap_next()
ntfs: convert iomap ops to ->iomap_next()
ntfs3: convert iomap ops to ->iomap_next()
btrfs: convert iomap ops to ->iomap_next()
xfs: convert iomap ops to ->iomap_next()
iomap: add ->iomap_next()
iomap: use GFP_NOWAIT when application for iomap_dio_simple allocations
iomap: decouple simple direct I/O reads from iomap_dio_rw
...
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