kernel-hacking-2024-linux-s.../Documentation
Linus Torvalds 35219bc5c7 vfs-6.12.netfs
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Merge tag 'vfs-6.12.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This contains the work to improve read/write performance for the new
  netfs library.

  The main performance enhancing changes are:

   - Define a structure, struct folio_queue, and a new iterator type,
     ITER_FOLIOQ, to hold a buffer as a replacement for ITER_XARRAY. See
     that patch for questions about naming and form.

     ITER_FOLIOQ is provided as a replacement for ITER_XARRAY. The
     problem with an xarray is that accessing it requires the use of a
     lock (typically the RCU read lock) - and this means that we can't
     supply iterate_and_advance() with a step function that might sleep
     (crypto for example) without having to drop the lock between pages.
     ITER_FOLIOQ is the iterator for a chain of folio_queue structs,
     where each folio_queue holds a small list of folios. A folio_queue
     struct is a simpler structure than xarray and is not subject to
     concurrent manipulation by the VM. folio_queue is used rather than
     a bvec[] as it can form lists of indefinite size, adding to one end
     and removing from the other on the fly.

   - Provide a copy_folio_from_iter() wrapper.

   - Make cifs RDMA support ITER_FOLIOQ.

   - Use folio queues in the write-side helpers instead of xarrays.

   - Add a function to reset the iterator in a subrequest.

   - Simplify the write-side helpers to use sheaves to skip gaps rather
     than trying to work out where gaps are.

   - In afs, make the read subrequests asynchronous, putting them into
     work items to allow the next patch to do progressive
     unlocking/reading.

   - Overhaul the read-side helpers to improve performance.

   - Fix the caching of a partial block at the end of a file.

   - Allow a store to be cancelled.

  Then some changes for cifs to make it use folio queues instead of
  xarrays for crypto bufferage:

   - Use raw iteration functions rather than manually coding iteration
     when hashing data.

   - Switch to using folio_queue for crypto buffers.

   - Remove the xarray bits.

  Make some adjustments to the /proc/fs/netfs/stats file such that:

   - All the netfs stats lines begin 'Netfs:' but change this to
     something a bit more useful.

   - Add a couple of stats counters to track the numbers of skips and
     waits on the per-inode writeback serialisation lock to make it
     easier to check for this as a source of performance loss.

  Miscellaneous work:

   - Ensure that the sb_writers lock is taken around
     vfs_{set,remove}xattr() in the cachefiles code.

   - Reduce the number of conditional branches in netfs_perform_write().

   - Move the CIFS_INO_MODIFIED_ATTR flag to the netfs_inode struct and
     remove cifs_post_modify().

   - Move the max_len/max_nr_segs members from netfs_io_subrequest to
     netfs_io_request as they're only needed for one subreq at a time.

   - Add an 'unknown' source value for tracing purposes.

   - Remove NETFS_COPY_TO_CACHE as it's no longer used.

   - Set the request work function up front at allocation time.

   - Use bh-disabling spinlocks for rreq->lock as cachefiles completion
     may be run from block-filesystem DIO completion in softirq context.

   - Remove fs/netfs/io.c"

* tag 'vfs-6.12.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (25 commits)
  docs: filesystems: corrected grammar of netfs page
  cifs: Don't support ITER_XARRAY
  cifs: Switch crypto buffer to use a folio_queue rather than an xarray
  cifs: Use iterate_and_advance*() routines directly for hashing
  netfs: Cancel dirty folios that have no storage destination
  cachefiles, netfs: Fix write to partial block at EOF
  netfs: Remove fs/netfs/io.c
  netfs: Speed up buffered reading
  afs: Make read subreqs async
  netfs: Simplify the writeback code
  netfs: Provide an iterator-reset function
  netfs: Use new folio_queue data type and iterator instead of xarray iter
  cifs: Provide the capability to extract from ITER_FOLIOQ to RDMA SGEs
  iov_iter: Provide copy_folio_from_iter()
  mm: Define struct folio_queue and ITER_FOLIOQ to handle a sequence of folios
  netfs: Use bh-disabling spinlocks for rreq->lock
  netfs: Set the request work function upon allocation
  netfs: Remove NETFS_COPY_TO_CACHE
  netfs: Reserve netfs_sreq_source 0 as unset/unknown
  netfs: Move max_len/max_nr_segs from netfs_io_subrequest to netfs_io_stream
  ...
2024-09-16 12:13:31 +02:00
..
ABI docs: ABI: update OCP TimeCard sysfs entries 2024-09-03 15:37:48 +02:00
accel
accounting
admin-guide vfs-6.12.procfs 2024-09-16 09:36:59 +02:00
arch arm64 updates for 6.12 2024-09-16 06:55:07 +02:00
block
bpf
cdrom
core-api workqueue: doc: Fix function name, remove markers 2024-08-05 18:33:36 -10:00
cpu-freq
crypto
dev-tools selftests: rds: add testing infrastructure 2024-08-09 13:18:46 +01:00
devicetree Thermal control updates for 6.12-rc1 2024-09-16 08:05:54 +02:00
doc-guide
driver-api Thermal control updates for 6.12-rc1 2024-09-16 08:05:54 +02:00
fault-injection
fb
features
filesystems vfs-6.12.netfs 2024-09-16 12:13:31 +02:00
firmware-guide
firmware_class
fpga
gpu
hid
hwmon
i2c
iio
images
infiniband
input
isdn
kbuild Documentation/llvm: turn make command for ccache into code block 2024-08-16 21:34:12 +09:00
kernel-hacking
leds
litmus-tests
livepatch
locking
maintainer
mhi
misc-devices
mm
netlabel
netlink Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-12 17:11:24 -07:00
networking Documentation: networking: Fix missing PSE documentation and grammar issues 2024-09-13 19:59:53 -07:00
nvdimm
nvme
PCI
pcmcia
peci
power Documentation: PM: Discourage use of deprecated macros 2024-09-04 14:37:57 +02:00
process docs: netdev: document guidance on cleanup.h 2024-09-05 11:00:35 +02:00
RCU
rust docs: rust: remove unintended blockquote in Quick Start 2024-08-27 22:44:29 +02:00
scheduler
scsi
security
sound
sphinx
sphinx-static
spi
staging
target
tee
timers
tools
trace
translations
usb
userspace-api media: v4l: Fix missing tabular column hint for Y14P format 2024-07-30 08:36:29 +02:00
virt arm64 updates for 6.12 2024-09-16 06:55:07 +02:00
w1
watchdog
wmi platform/x86: msi-wmi-platform: Fix spelling mistakes 2024-07-31 12:37:01 +03:00
.gitignore
atomic_bitops.txt
atomic_t.txt
Changes
CodingStyle
conf.py
docutils.conf
dontdiff
index.rst
Kconfig
Makefile
memory-barriers.txt
SubmittingPatches
subsystem-apis.rst