mirror_zfs/module
Alexander Motin c84670950a FreeBSD: Use unmapped I/O for scattered/gang ABD buffers
Many FreeBSD disk drivers support "unmapped" I/O mode, when data
buffer represented not with a virtually contiguous KVA-mapped address
range, but with a list of physical memory pages.  Originally it was
designed to do I/O from buffers without KVA mapping (unmapped).  But
moving virtual addresses out of equation allows us to operate even
non-contiguous data buffers with one condition: all buffer discon-
tinuities must be aligned to memory page borders.

Doing I/O to capable GEOM device this patch traverses through non-
linear ABD buffers, validating the chunks borders.  If the condition
is met, it supplies GEOM with the list of original physical memory
pages instead of copying the data into temporary contiguous buffer.
On capable hardware on pools with ashift=12 and default ABD chunk of
4KB it should handle all the I/O without additional memory copying.

Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes #12320
2021-09-14 12:37:02 -07:00
..
avl Fix various typos 2021-04-07 13:27:11 -07:00
icp Replace ZoL with OpenZFS where applicable 2021-05-10 12:16:46 -07:00
lua cppcheck: integrete cppcheck 2021-01-26 16:12:26 -08:00
nvpair Links in Source Files 2020-09-02 09:42:12 -07:00
os FreeBSD: Use unmapped I/O for scattered/gang ABD buffers 2021-09-14 12:37:02 -07:00
spl Cleanup linux module kbuild files 2020-06-10 09:24:15 -07:00
unicode Fix various typos 2021-04-07 13:27:11 -07:00
zcommon Fix AVX512BW Fletcher code on AVX512-but-not-BW machines 2021-05-10 12:05:36 -07:00
zfs Move gethrtime() calls out of vdev queue lock 2021-09-14 12:35:53 -07:00
zstd Fix build with KASAN 2021-06-29 13:14:42 -07:00
.gitignore Cleanup linux module kbuild files 2020-06-10 09:24:15 -07:00
Kbuild.in Add zstd support to zfs 2020-08-20 10:30:06 -07:00
Makefile.bsd Restore FreeBSD resource usage accounting 2021-02-19 22:34:33 -08:00
Makefile.in FreeBSD module --enable-debug --enable-invariants 2021-03-05 12:16:41 -08:00