c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2026-05-25 11:47:43 +03:00
Code Issues Packages Projects Releases Wiki Activity

Wire O_DIRECT also to Uncached I/O (#17218)

Browse Source 
Before Direct I/O was implemented, I've implemented lighter version
I called Uncached I/O.  It uses normal DMU/ARC data path with some
optimizations, but evicts data from caches as soon as possible and
reasonable.  Originally I wired it only to a primarycache property,
but now completing the integration all the way up to the VFS.

While Direct I/O has the lowest possible memory bandwidth usage,
it also has a significant number of limitations.  It require I/Os
to be page aligned, does not allow speculative prefetch, etc.  The
Uncached I/O does not have those limitations, but instead require
additional memory copy, though still one less than regular cached
I/O.  As such it should fill the gap in between.  Considering this
I've disabled annoying EINVAL errors on misaligned requests, adding
a tunable for those who wants to test their applications.

To pass the information between the layers I had to change a number
of APIs.  But as side effect upper layers can now control not only
the caching, but also speculative prefetch.  I haven't wired it to
VFS yet, since it require looking on some OS specifics.  But while
there I've implemented speculative prefetch of indirect blocks for
Direct I/O, controllable via all the same mechanisms.

Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Fixes #17027
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Alexander Motin
2025-05-13 17:26:55 -04:00
committed by GitHub
parent e2ba0f7643
commit 734eba251d
35 changed files with 397 additions and 294 deletions
Download Patch File Download Diff File Expand all files Collapse all files
module/zfs/dmu_traverse.c
+5 -5
View File
@@ -297,7 +297,7 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
}
if (BP_GET_LEVEL(bp) > 0) {
uint32_t flags = ARC_FLAG_WAIT;
arc_flags_t flags = ARC_FLAG_WAIT;
int32_t i, ptidx, pidx;
uint32_t prefetchlimit;
int32_t epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
@@ -364,8 +364,8 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
kmem_free(czb, sizeof (zbookmark_phys_t));
} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
uint32_t flags = ARC_FLAG_WAIT;
uint32_t zio_flags = ZIO_FLAG_CANFAIL;
arc_flags_t flags = ARC_FLAG_WAIT;
zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
int32_t i;
int32_t epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
dnode_phys_t *child_dnp;
@@ -397,7 +397,7 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
break;
}
} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
uint32_t zio_flags = ZIO_FLAG_CANFAIL;
zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
arc_flags_t flags = ARC_FLAG_WAIT;
objset_phys_t *osp;
@@ -669,7 +669,7 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
/* See comment on ZIL traversal in dsl_scan_visitds. */
if (ds != NULL && !ds->ds_is_snapshot && !BP_IS_HOLE(rootbp)) {
zio_flag_t zio_flags = ZIO_FLAG_CANFAIL;
uint32_t flags = ARC_FLAG_WAIT;
arc_flags_t flags = ARC_FLAG_WAIT;
objset_phys_t *osp;
arc_buf_t *buf;
ASSERT(!BP_IS_REDACTED(rootbp));