mirror_zfs/include/os/linux/kernel/linux
Alexander Motin 70ea484e3e
Finally drop long disabled vdev cache.
It was a vdev level read cache, designed to aggregate many small
reads by speculatively issuing bigger reads instead and caching
the result.  But since it has almost no idea about what is going
on with exception of ZIO_FLAG_DONT_CACHE flag set by higher layers,
it was found to make more harm than good, for which reason it was
disabled for the past 12 years.  These days we have much better
instruments to enlarge the I/Os, such as speculative and prescient
prefetches, I/O scheduler, I/O aggregation etc.

Besides just the dead code removal this removes one extra mutex
lock/unlock per write inside vdev_cache_write(), not otherwise
disabled and trying to do some work.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #14953
2023-06-09 12:40:55 -07:00
..
blkdev_compat.h linux 6.3 compat: needs REQ_PREFLUSH | REQ_OP_WRITE 2023-03-31 09:46:22 -07:00
compiler_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dcache_compat.h Workaround for Linux PowerPC GPL-only cpu_has_feature() 2023-03-10 09:35:00 -08:00
kmap_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
mod_compat.h Finally drop long disabled vdev cache. 2023-06-09 12:40:55 -07:00
page_compat.h Linux 5.9 compat: NR_SLAB_RECLAIMABLE 2020-08-29 20:57:45 -07:00
percpu_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
simd_aarch64.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
simd_arm.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
simd_powerpc.h Refactor CONFIG_SPE check on Linux/powerpc 2023-03-15 10:30:42 -07:00
simd_x86.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
simd.h Add SHA2 SIMD feature tests for Linux 2023-03-02 13:52:04 -08:00
utsname_compat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vfs_compat.h Linux 6.3 compat: idmapped mount API changes 2023-04-10 14:15:36 -07:00
xattr_compat.h Linux 6.3 compat: idmapped mount API changes 2023-04-10 14:15:36 -07:00