Author: markj Date: Thu Jan 9 19:17:42 2020 New Revision: 356563 URL: https://svnweb.freebsd.org/changeset/base/356563
Log: UMA: Don't destroy zones after the system shutdown process starts. Some kernel subsystems, notably ZFS, will destroy UMA zones from a shutdown eventhandler. This causes the zone to be drained. For slabs that are mapped into KVA this can be very expensive and so it needlessly delays the shutdown process. Add a new state to the "booted" variable, BOOT_SHUTDOWN. Once kern_reboot() starts invoking shutdown handlers, turn uma_zdestroy() into a no-op, provided that the zone does not have a custom finalization routine. PR: 242427 Reviewed by: jeff, kib, rlibby MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D23066 Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Thu Jan 9 19:13:09 2020 (r356562) +++ head/sys/vm/uma_core.c Thu Jan 9 19:17:42 2020 (r356563) @@ -158,8 +158,14 @@ SYSCTL_ULONG(_vm, OID_AUTO, uma_kmem_total, CTLFLAG_RD "UMA kernel memory usage"); /* Is the VM done starting up? */ -static enum { BOOT_COLD = 0, BOOT_STRAPPED, BOOT_PAGEALLOC, BOOT_BUCKETS, - BOOT_RUNNING } booted = BOOT_COLD; +static enum { + BOOT_COLD, + BOOT_STRAPPED, + BOOT_PAGEALLOC, + BOOT_BUCKETS, + BOOT_RUNNING, + BOOT_SHUTDOWN, +} booted = BOOT_COLD; /* * This is the handle used to schedule events that need to happen @@ -265,6 +271,7 @@ static int hash_expand(struct uma_hash *, struct uma_h static void hash_free(struct uma_hash *hash); static void uma_timeout(void *); static void uma_startup3(void); +static void uma_shutdown(void); static void *zone_alloc_item(uma_zone_t, void *, int, int); static void zone_free_item(uma_zone_t, void *, void *, enum zfreeskip); static int zone_alloc_limit(uma_zone_t zone, int count, int flags); @@ -1408,8 +1415,7 @@ startup_alloc(uma_zone_t zone, vm_size_t bytes, int do case BOOT_PAGEALLOC: if (keg->uk_ppera > 1) break; - case BOOT_BUCKETS: - case BOOT_RUNNING: + default: #ifdef UMA_MD_SMALL_ALLOC keg->uk_allocf = (keg->uk_ppera > 1) ? page_alloc : uma_small_alloc; @@ -2337,7 +2343,7 @@ zone_ctor(void *mem, int size, void *udata, int flags) (UMA_ZONE_INHERIT | UMA_ZFLAG_INHERIT)); out: - if (__predict_true(booted == BOOT_RUNNING)) { + if (__predict_true(booted >= BOOT_RUNNING)) { zone_alloc_counters(zone, NULL); zone_alloc_sysctl(zone, NULL); } else { @@ -2465,7 +2471,7 @@ zone_foreach(void (*zfunc)(uma_zone_t, void *arg), voi * threaded, so locking isn't needed. Startup functions * are allowed to use M_WAITOK. */ - if (__predict_true(booted == BOOT_RUNNING)) + if (__predict_true(booted >= BOOT_RUNNING)) rw_rlock(&uma_rwlock); LIST_FOREACH(keg, &uma_kegs, uk_link) { LIST_FOREACH(zone, &keg->uk_zones, uz_link) @@ -2473,7 +2479,7 @@ zone_foreach(void (*zfunc)(uma_zone_t, void *arg), voi } LIST_FOREACH(zone, &uma_cachezones, uz_link) zfunc(zone, arg); - if (__predict_true(booted == BOOT_RUNNING)) + if (__predict_true(booted >= BOOT_RUNNING)) rw_runlock(&uma_rwlock); } @@ -2635,10 +2641,6 @@ uma_startup2(void) bucket_enable(); } -/* - * Initialize our callout handle - * - */ static void uma_startup3(void) { @@ -2653,8 +2655,18 @@ uma_startup3(void) callout_init(&uma_callout, 1); callout_reset(&uma_callout, UMA_TIMEOUT * hz, uma_timeout, NULL); booted = BOOT_RUNNING; + + EVENTHANDLER_REGISTER(shutdown_post_sync, uma_shutdown, NULL, + EVENTHANDLER_PRI_FIRST); } +static void +uma_shutdown(void) +{ + + booted = BOOT_SHUTDOWN; +} + static uma_keg_t uma_kcreate(uma_zone_t zone, size_t size, uma_init uminit, uma_fini fini, int align, uint32_t flags) @@ -2796,6 +2808,13 @@ void uma_zdestroy(uma_zone_t zone) { + /* + * Large slabs are expensive to reclaim, so don't bother doing + * unnecessary work if we're shutting down. + */ + if (booted == BOOT_SHUTDOWN && + zone->uz_fini == NULL && zone->uz_release == zone_release) + return; sx_slock(&uma_reclaim_lock); zone_free_item(zones, zone, NULL, SKIP_NONE); sx_sunlock(&uma_reclaim_lock); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
