Date: Thu, 16 Jan 2014 16:04:36 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r260767 - in stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs: . sys Message-ID: <201401161604.s0GG4aoZ073651@svn.freebsd.org>
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Author: avg Date: Thu Jan 16 16:04:36 2014 New Revision: 260767 URL: http://svnweb.freebsd.org/changeset/base/260767 Log: MFC r258633: MFV r255256: 3954 metaslabs continue to load even after hitting zfs_mg_alloc_failure limit Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Directory Properties: stable/8/sys/ (props changed) stable/8/sys/cddl/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c ============================================================================== --- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Thu Jan 16 16:04:20 2014 (r260766) +++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Thu Jan 16 16:04:36 2014 (r260767) @@ -58,7 +58,8 @@ int zfs_condense_pct = 200; /* * This value defines the number of allowed allocation failures per vdev. * If a device reaches this threshold in a given txg then we consider skipping - * allocations on that device. + * allocations on that device. The value of zfs_mg_alloc_failures is computed + * in zio_init() unless it has been overridden in /etc/system. */ int zfs_mg_alloc_failures = 0; @@ -69,6 +70,21 @@ SYSCTL_INT(_vfs_zfs, OID_AUTO, mg_alloc_ TUNABLE_INT("vfs.zfs.mg_alloc_failures", &zfs_mg_alloc_failures); /* + * The zfs_mg_noalloc_threshold defines which metaslab groups should + * be eligible for allocation. The value is defined as a percentage of + * a free space. Metaslab groups that have more free space than + * zfs_mg_noalloc_threshold are always eligible for allocations. Once + * a metaslab group's free space is less than or equal to the + * zfs_mg_noalloc_threshold the allocator will avoid allocating to that + * group unless all groups in the pool have reached zfs_mg_noalloc_threshold. + * Once all groups in the pool reach zfs_mg_noalloc_threshold then all + * groups are allowed to accept allocations. Gang blocks are always + * eligible to allocate on any metaslab group. The default value of 0 means + * no metaslab group will be excluded based on this criterion. + */ +int zfs_mg_noalloc_threshold = 0; + +/* * Metaslab debugging: when set, keeps all space maps in core to verify frees. */ static int metaslab_debug = 0; @@ -234,6 +250,53 @@ metaslab_compare(const void *x1, const v return (0); } +/* + * Update the allocatable flag and the metaslab group's capacity. + * The allocatable flag is set to true if the capacity is below + * the zfs_mg_noalloc_threshold. If a metaslab group transitions + * from allocatable to non-allocatable or vice versa then the metaslab + * group's class is updated to reflect the transition. + */ +static void +metaslab_group_alloc_update(metaslab_group_t *mg) +{ + vdev_t *vd = mg->mg_vd; + metaslab_class_t *mc = mg->mg_class; + vdev_stat_t *vs = &vd->vdev_stat; + boolean_t was_allocatable; + + ASSERT(vd == vd->vdev_top); + + mutex_enter(&mg->mg_lock); + was_allocatable = mg->mg_allocatable; + + mg->mg_free_capacity = ((vs->vs_space - vs->vs_alloc) * 100) / + (vs->vs_space + 1); + + mg->mg_allocatable = (mg->mg_free_capacity > zfs_mg_noalloc_threshold); + + /* + * The mc_alloc_groups maintains a count of the number of + * groups in this metaslab class that are still above the + * zfs_mg_noalloc_threshold. This is used by the allocating + * threads to determine if they should avoid allocations to + * a given group. The allocator will avoid allocations to a group + * if that group has reached or is below the zfs_mg_noalloc_threshold + * and there are still other groups that are above the threshold. + * When a group transitions from allocatable to non-allocatable or + * vice versa we update the metaslab class to reflect that change. + * When the mc_alloc_groups value drops to 0 that means that all + * groups have reached the zfs_mg_noalloc_threshold making all groups + * eligible for allocations. This effectively means that all devices + * are balanced again. + */ + if (was_allocatable && !mg->mg_allocatable) + mc->mc_alloc_groups--; + else if (!was_allocatable && mg->mg_allocatable) + mc->mc_alloc_groups++; + mutex_exit(&mg->mg_lock); +} + metaslab_group_t * metaslab_group_create(metaslab_class_t *mc, vdev_t *vd) { @@ -284,6 +347,7 @@ metaslab_group_activate(metaslab_group_t return; mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children); + metaslab_group_alloc_update(mg); if ((mgprev = mc->mc_rotor) == NULL) { mg->mg_prev = mg; @@ -369,6 +433,29 @@ metaslab_group_sort(metaslab_group_t *mg } /* + * Determine if a given metaslab group should skip allocations. A metaslab + * group should avoid allocations if its used capacity has crossed the + * zfs_mg_noalloc_threshold and there is at least one metaslab group + * that can still handle allocations. + */ +static boolean_t +metaslab_group_allocatable(metaslab_group_t *mg) +{ + vdev_t *vd = mg->mg_vd; + spa_t *spa = vd->vdev_spa; + metaslab_class_t *mc = mg->mg_class; + + /* + * A metaslab group is considered allocatable if its free capacity + * is greater than the set value of zfs_mg_noalloc_threshold, it's + * associated with a slog, or there are no other metaslab groups + * with free capacity greater than zfs_mg_noalloc_threshold. + */ + return (mg->mg_free_capacity > zfs_mg_noalloc_threshold || + mc != spa_normal_class(spa) || mc->mc_alloc_groups == 0); +} + +/* * ========================================================================== * Common allocator routines * ========================================================================== @@ -1317,6 +1404,8 @@ metaslab_sync_reassess(metaslab_group_t vdev_t *vd = mg->mg_vd; int64_t failures = mg->mg_alloc_failures; + metaslab_group_alloc_update(mg); + /* * Re-evaluate all metaslabs which have lower offsets than the * bonus area. @@ -1418,6 +1507,8 @@ metaslab_group_alloc(metaslab_group_t *m if (msp == NULL) return (-1ULL); + mutex_enter(&msp->ms_lock); + /* * If we've already reached the allowable number of failed * allocation attempts on this metaslab group then we @@ -1434,11 +1525,10 @@ metaslab_group_alloc(metaslab_group_t *m "asize %llu, failures %llu", spa_name(spa), mg->mg_vd->vdev_id, txg, mg, psize, asize, mg->mg_alloc_failures); + mutex_exit(&msp->ms_lock); return (-1ULL); } - mutex_enter(&msp->ms_lock); - /* * Ensure that the metaslab we have selected is still * capable of handling our request. It's possible that @@ -1591,6 +1681,21 @@ top: } else { allocatable = vdev_allocatable(vd); } + + /* + * Determine if the selected metaslab group is eligible + * for allocations. If we're ganging or have requested + * an allocation for the smallest gang block size + * then we don't want to avoid allocating to the this + * metaslab group. If we're in this condition we should + * try to allocate from any device possible so that we + * don't inadvertently return ENOSPC and suspend the pool + * even though space is still available. + */ + if (allocatable && CAN_FASTGANG(flags) && + psize > SPA_GANGBLOCKSIZE) + allocatable = metaslab_group_allocatable(mg); + if (!allocatable) goto next; Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h ============================================================================== --- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h Thu Jan 16 16:04:20 2014 (r260766) +++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h Thu Jan 16 16:04:36 2014 (r260767) @@ -24,7 +24,7 @@ */ /* - * Copyright (c) 2012 by Delphix. All rights reserved. + * Copyright (c) 2013 by Delphix. All rights reserved. */ #ifndef _SYS_METASLAB_IMPL_H @@ -45,6 +45,7 @@ struct metaslab_class { metaslab_group_t *mc_rotor; space_map_ops_t *mc_ops; uint64_t mc_aliquot; + uint64_t mc_alloc_groups; /* # of allocatable groups */ uint64_t mc_alloc; /* total allocated space */ uint64_t mc_deferred; /* total deferred frees */ uint64_t mc_space; /* total space (alloc + free) */ @@ -57,6 +58,8 @@ struct metaslab_group { uint64_t mg_aliquot; uint64_t mg_bonus_area; uint64_t mg_alloc_failures; + boolean_t mg_allocatable; /* can we allocate? */ + uint64_t mg_free_capacity; /* percentage free */ int64_t mg_bias; int64_t mg_activation_count; metaslab_class_t *mg_class; Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c ============================================================================== --- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Thu Jan 16 16:04:20 2014 (r260766) +++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Thu Jan 16 16:04:36 2014 (r260767) @@ -2417,7 +2417,7 @@ zio_alloc_zil(spa_t *spa, uint64_t txg, if (error) { error = metaslab_alloc(spa, spa_normal_class(spa), size, new_bp, 1, txg, old_bp, - METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID); + METASLAB_HINTBP_AVOID); } if (error == 0) {
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