diff options
| author | Brian Behlendorf <[email protected]> | 2011-03-30 18:59:17 -0700 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2011-04-21 13:49:31 -0700 |
| commit | 6a8f9b6bf0de3e3d09fcfa32e129c978e7641a8f (patch) | |
| tree | de1a73aad01836cd40e8473646f28c148df29e5c | |
| parent | 36df284366caa77cb40083d2e6bcce02274e2f05 (diff) | |
Enforce ARC meta-data limits
This change ensures the ARC meta-data limits are enforced. Without
this enforcement meta-data can grow to consume all of the ARC cache
pushing out data and hurting performance. The cache is aggressively
reclaimed but this is a soft and not a hard limit. The cache may
exceed the set limit briefly before being brought under control.
By default 25% of the ARC capacity can be used for meta-data. This
limit can be tuned by setting the 'zfs_arc_meta_limit' module option.
Once this limit is exceeded meta-data reclaim will occur in 3 percent
chunks, or may be tuned using 'arc_reduce_dnlc_percent'.
Closes #193
| -rw-r--r-- | module/zfs/arc.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 9ca8ad17d..02d8502fd 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -180,6 +180,7 @@ unsigned long zfs_arc_meta_limit = 0; int zfs_arc_grow_retry = 0; int zfs_arc_shrink_shift = 0; int zfs_arc_p_min_shift = 0; +int zfs_arc_reduce_dnlc_percent = 0; /* * Note that buffers can be in one of 6 states: @@ -2084,14 +2085,16 @@ arc_kmem_reap_now(arc_reclaim_strategy_t strat) kmem_cache_t *prev_data_cache = NULL; extern kmem_cache_t *zio_buf_cache[]; extern kmem_cache_t *zio_data_buf_cache[]; - #ifdef _KERNEL - if (arc_meta_used >= arc_meta_limit) { + int retry = 0; + + while ((arc_meta_used >= arc_meta_limit) && (retry < 10)) { /* * We are exceeding our meta-data cache limit. * Purge some DNLC entries to release holds on meta-data. */ dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent); + retry++; } #if defined(__i386) /* @@ -2157,6 +2160,10 @@ arc_reclaim_thread(void) arc_no_grow = FALSE; } + /* Keep meta data usage within limits */ + if (arc_meta_used >= arc_meta_limit) + arc_kmem_reap_now(ARC_RECLAIM_CONS); + arc_adjust(); if (arc_eviction_list != NULL) @@ -3583,6 +3590,9 @@ arc_init(void) if (zfs_arc_p_min_shift > 0) arc_p_min_shift = zfs_arc_p_min_shift; + if (zfs_arc_reduce_dnlc_percent > 0) + arc_reduce_dnlc_percent = zfs_arc_reduce_dnlc_percent; + /* if kmem_flags are set, lets try to use less memory */ if (kmem_debugging()) arc_c = arc_c / 2; @@ -4765,4 +4775,7 @@ MODULE_PARM_DESC(zfs_arc_max, "Maximum arc size"); module_param(zfs_arc_meta_limit, ulong, 0644); MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); + +module_param(arc_reduce_dnlc_percent, uint, 0644); +MODULE_PARM_DESC(arc_reduce_dnlc_percent, "Meta reclaim percentage"); #endif |