From 7ddbc411f2496f4d1716ac699cafeb4b897fb714 Mon Sep 17 00:00:00 2001 From: mav Date: Sat, 10 Nov 2018 01:58:37 +0000 Subject: [PATCH] Do not ignore arc_adjust() return value. This covers scenario when ARC may not shrink as fast as it could: 1. arc_size < arc_c and arc_adjust() does not evict anything, returning zero to arc_reclaim_thread(); 2. arc_available_memory() reports memory pressure, which can not be satisfied by arc_kmem_reap_now(); 3. arc_shrink() reduces arc_c and calls arc_adjust(), return of which is ignored; 4. even if the last arc_adjust() could not satisfy arc_size < arc_c, arc_reclaim_thread() will still go to sleep, since the first one returned zero. Reviewed by: allanjude, markj, sef MFC after: 2 weeks Sponsored by: iXsystems, Inc. Differential Revision: https://reviews.freebsd.org/D17927 --- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c index 37aa9bb3dc96..8616e7073bde 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c @@ -4565,7 +4565,7 @@ arc_flush(spa_t *spa, boolean_t retry) (void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry); } -void +uint64_t arc_shrink(int64_t to_free) { uint64_t asize = aggsum_value(&arc_size); @@ -4593,8 +4593,9 @@ arc_shrink(int64_t to_free) if (asize > arc_c) { DTRACE_PROBE2(arc__shrink_adjust, uint64_t, asize, uint64_t, arc_c); - (void) arc_adjust(); + return (arc_adjust()); } + return (0); } typedef enum free_memory_reason_t { @@ -4917,7 +4918,7 @@ arc_reclaim_thread(void *unused __unused) to_free = MAX(to_free, ptob(needfree)); #endif #endif - arc_shrink(to_free); + evicted += arc_shrink(to_free); } } else if (free_memory < arc_c >> arc_no_grow_shift) { arc_no_grow = B_TRUE;