From ac72fac3eaa569902cad88053167f7d74e7fe7e4 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Thu, 29 Aug 2013 10:56:49 -0800 Subject: Illumos #3954, #4080, #4081 3954 metaslabs continue to load even after hitting zfs_mg_alloc_failure limit 4080 zpool clear fails to clear pool 4081 need zfs_mg_noalloc_threshold Reviewed by: Adam Leventhal Reviewed by: Matthew Ahrens Approved by: Richard Lowe References: https://www.illumos.org/issues/3954 https://www.illumos.org/issues/4080 https://www.illumos.org/issues/4081 illumos/illumos-gate@22e30981d82a0b6dc89253596ededafae8655e00 Ported-by: Richard Yao Signed-off-by: Brian Behlendorf Issue #1775 --- module/zfs/metaslab.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++-- module/zfs/zfs_ioctl.c | 2 +- module/zfs/zio.c | 5 ++- 3 files changed, 113 insertions(+), 7 deletions(-) (limited to 'module') diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c index ff35910e3..f01a8893e 100644 --- a/module/zfs/metaslab.c +++ b/module/zfs/metaslab.c @@ -60,9 +60,25 @@ 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; +int zfs_mg_alloc_failures = 0; + +/* + * 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. @@ -223,6 +239,53 @@ metaslab_compare(const void *x1, const void *x2) 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) { @@ -273,6 +336,7 @@ metaslab_group_activate(metaslab_group_t *mg) 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; @@ -357,6 +421,29 @@ metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight) mutex_exit(&mg->mg_lock); } +/* + * 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 @@ -1301,6 +1388,8 @@ metaslab_sync_done(metaslab_t *msp, uint64_t txg) vdev_dirty(vd, VDD_METASLAB, msp, txg + 1); } + metaslab_group_alloc_update(mg); + /* * If the map is loaded but no longer active, evict it as soon as all * future allocations have synced. (If we unloaded it now and then @@ -1430,6 +1519,8 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t psize, uint64_t asize, 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 @@ -1446,11 +1537,10 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t psize, uint64_t asize, "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 @@ -1615,6 +1705,21 @@ 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; diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c index 8eb879d32..62387d968 100644 --- a/module/zfs/zfs_ioctl.c +++ b/module/zfs/zfs_ioctl.c @@ -5351,7 +5351,7 @@ zfs_ioctl_init(void) zfs_secpolicy_config, B_TRUE, POOL_CHECK_NONE); zfs_ioctl_register_pool(ZFS_IOC_CLEAR, zfs_ioc_clear, - zfs_secpolicy_config, B_TRUE, POOL_CHECK_SUSPENDED); + zfs_secpolicy_config, B_TRUE, POOL_CHECK_NONE); zfs_ioctl_register_pool(ZFS_IOC_POOL_REOPEN, zfs_ioc_pool_reopen, zfs_secpolicy_config, B_TRUE, POOL_CHECK_SUSPENDED); diff --git a/module/zfs/zio.c b/module/zfs/zio.c index 0ef9f28b4..bc9d5b920 100644 --- a/module/zfs/zio.c +++ b/module/zfs/zio.c @@ -227,7 +227,8 @@ zio_init(void) * The zio write taskqs have 1 thread per cpu, allow 1/2 of the taskqs * to fail 3 times per txg or 8 failures, whichever is greater. */ - zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8); + if (zfs_mg_alloc_failures == 0) + zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8); zio_inject_init(); @@ -2518,7 +2519,7 @@ zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, uint64_t size, if (error) { error = metaslab_alloc(spa, spa_normal_class(spa), size, new_bp, 1, txg, NULL, - METASLAB_FASTWRITE | METASLAB_GANG_AVOID); + METASLAB_FASTWRITE); } if (error == 0) { -- cgit v1.2.3