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-rw-r--r--module/zfs/arc.c27
1 files changed, 22 insertions, 5 deletions
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");