diff options
| -rw-r--r-- | man/man5/zfs-module-parameters.5 | 14 | ||||
| -rw-r--r-- | module/zfs/arc.c | 27 |
2 files changed, 36 insertions, 5 deletions
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5 index 444e74748..893bbf652 100644 --- a/man/man5/zfs-module-parameters.5 +++ b/man/man5/zfs-module-parameters.5 @@ -201,6 +201,20 @@ Default value: \fB200\fR%. .sp .ne 2 .na +\fBl2arc_meta_percent\fR (int) +.ad +.RS 12n +Percent of ARC size allowed for L2ARC-only headers. +Since L2ARC buffers are not evicted on memory pressure, too large amount of +headers on system with irrationaly large L2ARC can render it slow or unusable. +This parameter limits L2ARC writes and rebuild to achieve it. +.sp +Default value: \fB33\fR%. +.RE + +.sp +.ne 2 +.na \fBl2arc_trim_ahead\fR (ulong) .ad .RS 12n diff --git a/module/zfs/arc.c b/module/zfs/arc.c index bd1a993dc..70565cc25 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -823,6 +823,7 @@ unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ int l2arc_feed_again = B_TRUE; /* turbo warmup */ int l2arc_norw = B_FALSE; /* no reads during writes */ +int l2arc_meta_percent = 33; /* limit on headers size */ /* * L2ARC Internals @@ -4988,9 +4989,6 @@ arc_adapt(int bytes, arc_state_t *state) int64_t mrug_size = zfs_refcount_count(&arc_mru_ghost->arcs_size); int64_t mfug_size = zfs_refcount_count(&arc_mfu_ghost->arcs_size); - if (state == arc_l2c_only) - return; - ASSERT(bytes > 0); /* * Adapt the target size of the MRU list: @@ -9144,6 +9142,15 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) return (write_asize); } +static boolean_t +l2arc_hdr_limit_reached(void) +{ + int64_t s = aggsum_upper_bound(&astat_l2_hdr_size); + + return (arc_reclaim_needed() || (s > arc_meta_limit * 3 / 4) || + (s > (arc_warm ? arc_c : arc_c_max) * l2arc_meta_percent / 100)); +} + /* * This thread feeds the L2ARC at regular intervals. This is the beating * heart of the L2ARC. @@ -9211,7 +9218,7 @@ l2arc_feed_thread(void *unused) /* * Avoid contributing to memory pressure. */ - if (arc_reclaim_needed()) { + if (l2arc_hdr_limit_reached()) { ARCSTAT_BUMP(arcstat_l2_abort_lowmem); spa_config_exit(spa, SCL_L2ARC, dev); continue; @@ -9662,7 +9669,7 @@ l2arc_rebuild(l2arc_dev_t *dev) * online the L2ARC dev at a later time (or re-import the pool) * to reconstruct it (when there's less memory pressure). */ - if (arc_reclaim_needed()) { + if (l2arc_hdr_limit_reached()) { ARCSTAT_BUMP(arcstat_l2_rebuild_abort_lowmem); cmn_err(CE_NOTE, "System running low on memory, " "aborting L2ARC rebuild."); @@ -10002,6 +10009,13 @@ l2arc_log_blk_restore(l2arc_dev_t *dev, const l2arc_log_blk_phys_t *lb, uint64_t size = 0, asize = 0; uint64_t log_entries = dev->l2ad_log_entries; + /* + * Usually arc_adapt() is called only for data, not headers, but + * since we may allocate significant amount of memory here, let ARC + * grow its arc_c. + */ + arc_adapt(log_entries * HDR_L2ONLY_SIZE, arc_l2c_only); + for (int i = log_entries - 1; i >= 0; i--) { /* * Restore goes in the reverse temporal direction to preserve @@ -10538,6 +10552,9 @@ ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_again, INT, ZMOD_RW, ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, norw, INT, ZMOD_RW, "No reads during writes"); +ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, meta_percent, INT, ZMOD_RW, + "Percent of ARC size allowed for L2ARC-only headers"); + ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, rebuild_enabled, INT, ZMOD_RW, "Rebuild the L2ARC when importing a pool"); |