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5368 ARC should cache more metadata

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Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Matthew Ahrens <mahrens@delphix.com>

illumos/illumos-gate@3a5286a1cf
This commit is contained in:
Xin LI 2014-12-06 00:45:27 +00:00
parent e0436c62e3
commit abdfac3e52
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/vendor-sys/illumos/dist/; revision=275549
1 changed files with 55 additions and 2 deletions
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57
uts/common/fs/zfs/arc.c
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@ -196,6 +196,7 @@ static boolean_t arc_warm;
uint64_t zfs_arc_max;
uint64_t zfs_arc_min;
uint64_t zfs_arc_meta_limit = 0;
uint64_t zfs_arc_meta_min = 0;
int zfs_arc_grow_retry = 0;
int zfs_arc_shrink_shift = 0;
int zfs_arc_p_min_shift = 0;
@ -324,6 +325,7 @@ typedef struct arc_stats {
kstat_named_t arcstat_meta_used;
kstat_named_t arcstat_meta_limit;
kstat_named_t arcstat_meta_max;
kstat_named_t arcstat_meta_min;
} arc_stats_t;
static arc_stats_t arc_stats = {
@ -389,7 +391,8 @@ static arc_stats_t arc_stats = {
{ "duplicate_reads", KSTAT_DATA_UINT64 },
{ "arc_meta_used", KSTAT_DATA_UINT64 },
{ "arc_meta_limit", KSTAT_DATA_UINT64 },
{ "arc_meta_max", KSTAT_DATA_UINT64 }
{ "arc_meta_max", KSTAT_DATA_UINT64 },
{ "arc_meta_min", KSTAT_DATA_UINT64 }
};
#define ARCSTAT(stat) (arc_stats.stat.value.ui64)
@ -452,6 +455,7 @@ static arc_state_t *arc_l2c_only;
#define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */
#define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */
#define arc_meta_limit ARCSTAT(arcstat_meta_limit) /* max size for metadata */
#define arc_meta_min ARCSTAT(arcstat_meta_min) /* min size for metadata */
#define arc_meta_used ARCSTAT(arcstat_meta_used) /* size of metadata */
#define arc_meta_max ARCSTAT(arcstat_meta_max) /* max size of metadata */
@ -1779,7 +1783,6 @@ arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle,
arc_state_t *evicted_state;
uint64_t bytes_evicted = 0, skipped = 0, missed = 0;
arc_buf_hdr_t *ab, *ab_prev = NULL;
list_t *list = &state->arcs_list[type];
kmutex_t *hash_lock;
boolean_t have_lock;
void *stolen = NULL;
@ -1793,6 +1796,50 @@ arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle,
mutex_enter(&state->arcs_mtx);
mutex_enter(&evicted_state->arcs_mtx);
/*
* Decide which "type" (data vs metadata) to recycle from.
*
* If we are over the metadata limit, recycle from metadata.
* If we are under the metadata minimum, recycle from data.
* Otherwise, recycle from whichever type has the oldest (least
* recently accessed) header.
*/
if (recycle) {
arc_buf_hdr_t *data_hdr =
list_tail(&state->arcs_list[ARC_BUFC_DATA]);
arc_buf_hdr_t *metadata_hdr =
list_tail(&state->arcs_list[ARC_BUFC_METADATA]);
arc_buf_contents_t realtype;
if (data_hdr == NULL) {
realtype = ARC_BUFC_METADATA;
} else if (metadata_hdr == NULL) {
realtype = ARC_BUFC_DATA;
} else if (arc_meta_used >= arc_meta_limit) {
realtype = ARC_BUFC_METADATA;
} else if (arc_meta_used <= arc_meta_min) {
realtype = ARC_BUFC_DATA;
} else {
if (data_hdr->b_arc_access <
metadata_hdr->b_arc_access) {
realtype = ARC_BUFC_DATA;
} else {
realtype = ARC_BUFC_METADATA;
}
}
if (realtype != type) {
/*
* If we want to evict from a different list,
* we can not recycle, because DATA vs METADATA
* buffers are segregated into different kmem
* caches (and vmem arenas).
*/
type = realtype;
recycle = B_FALSE;
}
}
list_t *list = &state->arcs_list[type];
for (ab = list_tail(list); ab; ab = ab_prev) {
ab_prev = list_prev(list, ab);
/* prefetch buffers have a minimum lifespan */
@ -3755,6 +3802,12 @@ arc_init(void)
if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0)
arc_c_min = arc_meta_limit / 2;
if (zfs_arc_meta_min > 0) {
arc_meta_min = zfs_arc_meta_min;
} else {
arc_meta_min = arc_c_min / 2;
}
if (zfs_arc_grow_retry > 0)
arc_grow_retry = zfs_arc_grow_retry;