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authorMatthew Macy <[email protected]>2020-12-09 15:05:06 -0800
committerGitHub <[email protected]>2020-12-09 15:05:06 -0800
commit1e4732cbda8eb0c95901ed9f924b5a13bf24c76e (patch)
tree0a480e1fce09aaa2fe99a60575757e7da8409fe5 /module/zfs/arc.c
parentedb20ff3bab31f9e07578a7bf8279d67b821f29a (diff)
Decouple arc_read_done callback from arc buf instantiation
Add ARC_FLAG_NO_BUF to indicate that a buffer need not be instantiated. This fixes a ~20% performance regression on cached reads due to zfetch changes. Reviewed-by: Tony Nguyen <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Matt Macy <[email protected]> Closes #11220 Closes #11232
Diffstat (limited to 'module/zfs/arc.c')
-rw-r--r--module/zfs/arc.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 42c09e2e5..efc6bb138 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -5924,6 +5924,7 @@ arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
boolean_t noauth_read = BP_IS_AUTHENTICATED(bp) &&
(zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0;
boolean_t embedded_bp = !!BP_IS_EMBEDDED(bp);
+ boolean_t no_buf = *arc_flags & ARC_FLAG_NO_BUF;
int rc = 0;
ASSERT(!embedded_bp ||
@@ -5998,7 +5999,7 @@ top:
}
ASSERT(*arc_flags & ARC_FLAG_NOWAIT);
- if (done) {
+ if (done && !no_buf) {
arc_callback_t *acb = NULL;
acb = kmem_zalloc(sizeof (arc_callback_t),
@@ -6027,7 +6028,7 @@ top:
ASSERT(hdr->b_l1hdr.b_state == arc_mru ||
hdr->b_l1hdr.b_state == arc_mfu);
- if (done) {
+ if (done && !no_buf) {
if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) {
/*
* This is a demand read which does not have to