Author: jpaetzel Date: Tue Mar 7 18:31:03 2017 New Revision: 314874 URL: https://svnweb.freebsd.org/changeset/base/314874
Log: MFC 313879 MVF: 313876 7504 kmem_reap hangs spa_sync and administrative tasks illumos/illumos-gate@405a5a0f5c3ab36cb76559467d1a62ba648bd809 https://github.com/illumos/illumos-gate/commit/405a5a0f5c3ab36cb76559467d1a62ba648bd80 https://www.illumos.org/issues/7504 We see long spa_sync(). We are waiting to hold dp_config_rwlock for writer. Some other thread holds dp_config_rwlock for reader, then calls arc_get_data_buf(), which finds that arc_is_overflowing()==B_TRUE. So it waits (while holding dp_config_rwlock for reader) for arc_reclaim_thread to signal arc_reclaim_waiters_cv. Before signaling, arc_reclaim_thread does arc_kmem_reap_now(), which takes ~seconds. Author: Matthew Ahrens <mahr...@delphix.com> Reviewed by: George Wilson <george.wil...@delphix.com> Reviewed by: Prakash Surya <prakash.su...@delphix.com> Approved by: Dan McDonald <dan...@omniti.com> Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c ============================================================================== --- stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Tue Mar 7 18:27:35 2017 (r314873) +++ stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Tue Mar 7 18:31:03 2017 (r314874) @@ -4084,7 +4084,6 @@ arc_reclaim_thread(void *dummy __unused) mutex_enter(&arc_reclaim_lock); while (!arc_reclaim_thread_exit) { - int64_t free_memory = arc_available_memory(); uint64_t evicted = 0; /* @@ -4103,6 +4102,14 @@ arc_reclaim_thread(void *dummy __unused) mutex_exit(&arc_reclaim_lock); + /* + * We call arc_adjust() before (possibly) calling + * arc_kmem_reap_now(), so that we can wake up + * arc_get_data_buf() sooner. + */ + evicted = arc_adjust(); + + int64_t free_memory = arc_available_memory(); if (free_memory < 0) { arc_no_grow = B_TRUE; @@ -4136,8 +4143,6 @@ arc_reclaim_thread(void *dummy __unused) arc_no_grow = B_FALSE; } - evicted = arc_adjust(); - mutex_enter(&arc_reclaim_lock); /* _______________________________________________ svn-src-stable-10@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-stable-10 To unsubscribe, send any mail to "svn-src-stable-10-unsubscr...@freebsd.org"
