Author: mav Date: Fri Mar 24 09:37:00 2017 New Revision: 315896 URL: https://svnweb.freebsd.org/changeset/base/315896
Log: MFV r315290, r315291: 7303 dynamic metaslab selection illumos/illumos-gate@8363e80ae72609660f6090766ca8c2c18aa53f0c https://github.com/illumos/illumos-gate/commit/8363e80ae72609660f6090766ca8c2c18 https://www.illumos.org/issues/7303 This change introduces a new weighting algorithm to improve metaslab selection. The new weighting algorithm relies on the SPACEMAP_HISTOGRAM feature. As a result, the metaslab weight now encodes the type of weighting algorithm used (size-based vs segment-based). This also introduce a new allocation tracing facility and two new dcmds to help debug allocation problems. Each zio now contains a zio_alloc_list_t structure that is populated as the zio goes through the allocations stage. Here's an example of how to use the tracing facility: > c5ec000::print zio_t io_alloc_list | ::walk list | ::metaslab_trace MSID DVA ASIZE WEIGHT RESULT VDEV - 0 400 0 NOT_ALLOCATABLE ztest.0a - 0 400 0 NOT_ALLOCATABLE ztest.0a - 0 400 0 ENOSPC ztest.0a - 0 200 0 NOT_ALLOCATABLE ztest.0a - 0 200 0 NOT_ALLOCATABLE ztest.0a - 0 200 0 ENOSPC ztest.0a 1 0 400 1 x 8M 17b1a00 ztest.0a > 1ff2400::print zio_t io_alloc_list | ::walk list | ::metaslab_trace MSID DVA ASIZE WEIGHT RESULT VDEV - 0 200 0 NOT_ALLOCATABLE mirror-2 - 0 200 0 NOT_ALLOCATABLE mirror-0 1 0 200 1 x 4M 112ae00 mirror-1 - 1 200 0 NOT_ALLOCATABLE mirror-2 - 1 200 0 NOT_ALLOCATABLE mirror-0 1 1 200 1 x 4M 112b000 mirror-1 - 2 200 0 NOT_ALLOCATABLE mirror-2 If the metaslab is using segment-based weighting then the WEIGHT column will display the number of segments available in the bucket where the allocation attempt was made. Author: George Wilson <george.wil...@delphix.com> Reviewed by: Alex Reece <a...@delphix.com> Reviewed by: Chris Siden <christopher.si...@delphix.com> Reviewed by: Dan Kimmel <dan.kim...@delphix.com> Reviewed by: Matthew Ahrens <mahr...@delphix.com> Reviewed by: Paul Dagnelie <paul.dagne...@delphix.com> Reviewed by: Pavel Zakharov <pavel.zakha...@delphix.com> Reviewed by: Prakash Surya <prakash.su...@delphix.com> Reviewed by: Don Brady <don.br...@intel.com> Approved by: Richard Lowe <richl...@richlowe.net> Modified: head/cddl/contrib/opensolaris/cmd/zdb/zdb.c head/cddl/contrib/opensolaris/cmd/ztest/ztest.c head/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c head/sys/cddl/compat/opensolaris/kern/opensolaris_kstat.c head/sys/cddl/compat/opensolaris/sys/kstat.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/space_map.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zfs_debug.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c Directory Properties: head/cddl/contrib/opensolaris/ (props changed) head/cddl/contrib/opensolaris/cmd/zdb/ (props changed) head/sys/cddl/contrib/opensolaris/ (props changed) Modified: head/cddl/contrib/opensolaris/cmd/zdb/zdb.c ============================================================================== --- head/cddl/contrib/opensolaris/cmd/zdb/zdb.c Fri Mar 24 08:06:00 2017 (r315895) +++ head/cddl/contrib/opensolaris/cmd/zdb/zdb.c Fri Mar 24 09:37:00 2017 (r315896) @@ -2589,10 +2589,21 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb) if (!dump_opt['L']) { vdev_t *rvd = spa->spa_root_vdev; + + /* + * We are going to be changing the meaning of the metaslab's + * ms_tree. Ensure that the allocator doesn't try to + * use the tree. + */ + spa->spa_normal_class->mc_ops = &zdb_metaslab_ops; + spa->spa_log_class->mc_ops = &zdb_metaslab_ops; + for (uint64_t c = 0; c < rvd->vdev_children; c++) { vdev_t *vd = rvd->vdev_child[c]; + metaslab_group_t *mg = vd->vdev_mg; for (uint64_t m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *msp = vd->vdev_ms[m]; + ASSERT3P(msp->ms_group, ==, mg); mutex_enter(&msp->ms_lock); metaslab_unload(msp); @@ -2613,8 +2624,6 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb) (longlong_t)m, (longlong_t)vd->vdev_ms_count); - msp->ms_ops = &zdb_metaslab_ops; - /* * We don't want to spend the CPU * manipulating the size-ordered @@ -2624,7 +2633,10 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb) msp->ms_tree->rt_ops = NULL; VERIFY0(space_map_load(msp->ms_sm, msp->ms_tree, SM_ALLOC)); - msp->ms_loaded = B_TRUE; + + if (!msp->ms_loaded) { + msp->ms_loaded = B_TRUE; + } } mutex_exit(&msp->ms_lock); } @@ -2646,8 +2658,10 @@ zdb_leak_fini(spa_t *spa) vdev_t *rvd = spa->spa_root_vdev; for (int c = 0; c < rvd->vdev_children; c++) { vdev_t *vd = rvd->vdev_child[c]; + metaslab_group_t *mg = vd->vdev_mg; for (int m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *msp = vd->vdev_ms[m]; + ASSERT3P(mg, ==, msp->ms_group); mutex_enter(&msp->ms_lock); /* @@ -2661,7 +2675,10 @@ zdb_leak_fini(spa_t *spa) * from the ms_tree. */ range_tree_vacate(msp->ms_tree, zdb_leak, vd); - msp->ms_loaded = B_FALSE; + + if (msp->ms_loaded) { + msp->ms_loaded = B_FALSE; + } mutex_exit(&msp->ms_lock); } Modified: head/cddl/contrib/opensolaris/cmd/ztest/ztest.c ============================================================================== --- head/cddl/contrib/opensolaris/cmd/ztest/ztest.c Fri Mar 24 08:06:00 2017 (r315895) +++ head/cddl/contrib/opensolaris/cmd/ztest/ztest.c Fri Mar 24 09:37:00 2017 (r315896) @@ -173,7 +173,7 @@ static const ztest_shared_opts_t ztest_o .zo_mirrors = 2, .zo_raidz = 4, .zo_raidz_parity = 1, - .zo_vdev_size = SPA_MINDEVSIZE * 2, + .zo_vdev_size = SPA_MINDEVSIZE * 4, /* 256m default size */ .zo_datasets = 7, .zo_threads = 23, .zo_passtime = 60, /* 60 seconds */ Modified: head/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c ============================================================================== --- head/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c Fri Mar 24 08:06:00 2017 (r315895) +++ head/cddl/contrib/opensolaris/lib/libzpool/common/kernel.c Fri Mar 24 09:37:00 2017 (r315896) @@ -97,6 +97,11 @@ kstat_create(char *module, int instance, /*ARGSUSED*/ void +kstat_named_init(kstat_named_t *knp, const char *name, uchar_t type) +{} + +/*ARGSUSED*/ +void kstat_install(kstat_t *ksp) {} Modified: head/sys/cddl/compat/opensolaris/kern/opensolaris_kstat.c ============================================================================== --- head/sys/cddl/compat/opensolaris/kern/opensolaris_kstat.c Fri Mar 24 08:06:00 2017 (r315895) +++ head/sys/cddl/compat/opensolaris/kern/opensolaris_kstat.c Fri Mar 24 09:37:00 2017 (r315896) @@ -129,3 +129,19 @@ kstat_delete(kstat_t *ksp) sysctl_ctx_free(&ksp->ks_sysctl_ctx); free(ksp, M_KSTAT); } + +void +kstat_set_string(char *dst, const char *src) +{ + + bzero(dst, KSTAT_STRLEN); + (void) strncpy(dst, src, KSTAT_STRLEN - 1); +} + +void +kstat_named_init(kstat_named_t *knp, const char *name, uchar_t data_type) +{ + + kstat_set_string(knp->name, name); + knp->data_type = data_type; +} Modified: head/sys/cddl/compat/opensolaris/sys/kstat.h ============================================================================== --- head/sys/cddl/compat/opensolaris/sys/kstat.h Fri Mar 24 08:06:00 2017 (r315895) +++ head/sys/cddl/compat/opensolaris/sys/kstat.h Fri Mar 24 09:37:00 2017 (r315896) @@ -69,5 +69,7 @@ kstat_t *kstat_create(char *module, int uchar_t type, ulong_t ndata, uchar_t flags); void kstat_install(kstat_t *ksp); void kstat_delete(kstat_t *ksp); +void kstat_set_string(char *, const char *); +void kstat_named_init(kstat_named_t *, const char *, uchar_t); #endif /* _OPENSOLARIS_SYS_KSTAT_H_ */ Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Fri Mar 24 08:06:00 2017 (r315895) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Fri Mar 24 09:37:00 2017 (r315896) @@ -41,11 +41,6 @@ SYSCTL_NODE(_vfs_zfs, OID_AUTO, metaslab #define GANG_ALLOCATION(flags) \ ((flags) & (METASLAB_GANG_CHILD | METASLAB_GANG_HEADER)) -#define METASLAB_WEIGHT_PRIMARY (1ULL << 63) -#define METASLAB_WEIGHT_SECONDARY (1ULL << 62) -#define METASLAB_ACTIVE_MASK \ - (METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY) - uint64_t metaslab_aliquot = 512ULL << 10; uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */ SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, gang_bang, CTLFLAG_RWTUN, @@ -55,7 +50,7 @@ SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, /* * The in-core space map representation is more compact than its on-disk form. * The zfs_condense_pct determines how much more compact the in-core - * space_map representation must be before we compact it on-disk. + * space map representation must be before we compact it on-disk. * Values should be greater than or equal to 100. */ int zfs_condense_pct = 200; @@ -153,7 +148,7 @@ SYSCTL_QUAD(_vfs_zfs_metaslab, OID_AUTO, /* * The minimum free space, in percent, which must be available * in a space map to continue allocations in a first-fit fashion. - * Once the space_map's free space drops below this level we dynamically + * Once the space map's free space drops below this level we dynamically * switch to using best-fit allocations. */ int metaslab_df_free_pct = 4; @@ -230,7 +225,38 @@ SYSCTL_INT(_vfs_zfs_metaslab, OID_AUTO, &metaslab_bias_enabled, 0, "Enable metaslab group biasing"); -static uint64_t metaslab_fragmentation(metaslab_t *); +/* + * Enable/disable segment-based metaslab selection. + */ +boolean_t zfs_metaslab_segment_weight_enabled = B_TRUE; + +/* + * When using segment-based metaslab selection, we will continue + * allocating from the active metaslab until we have exhausted + * zfs_metaslab_switch_threshold of its buckets. + */ +int zfs_metaslab_switch_threshold = 2; + +/* + * Internal switch to enable/disable the metaslab allocation tracing + * facility. + */ +boolean_t metaslab_trace_enabled = B_TRUE; + +/* + * Maximum entries that the metaslab allocation tracing facility will keep + * in a given list when running in non-debug mode. We limit the number + * of entries in non-debug mode to prevent us from using up too much memory. + * The limit should be sufficiently large that we don't expect any allocation + * to every exceed this value. In debug mode, the system will panic if this + * limit is ever reached allowing for further investigation. + */ +uint64_t metaslab_trace_max_entries = 5000; + +static uint64_t metaslab_weight(metaslab_t *); +static void metaslab_set_fragmentation(metaslab_t *); + +kmem_cache_t *metaslab_alloc_trace_cache; /* * ========================================================================== @@ -475,11 +501,6 @@ metaslab_class_expandable_space(metaslab return (space); } -/* - * ========================================================================== - * Metaslab groups - * ========================================================================== - */ static int metaslab_compare(const void *x1, const void *x2) { @@ -505,6 +526,57 @@ metaslab_compare(const void *x1, const v } /* + * Verify that the space accounting on disk matches the in-core range_trees. + */ +void +metaslab_verify_space(metaslab_t *msp, uint64_t txg) +{ + spa_t *spa = msp->ms_group->mg_vd->vdev_spa; + uint64_t allocated = 0; + uint64_t freed = 0; + uint64_t sm_free_space, msp_free_space; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + if ((zfs_flags & ZFS_DEBUG_METASLAB_VERIFY) == 0) + return; + + /* + * We can only verify the metaslab space when we're called + * from syncing context with a loaded metaslab that has an allocated + * space map. Calling this in non-syncing context does not + * provide a consistent view of the metaslab since we're performing + * allocations in the future. + */ + if (txg != spa_syncing_txg(spa) || msp->ms_sm == NULL || + !msp->ms_loaded) + return; + + sm_free_space = msp->ms_size - space_map_allocated(msp->ms_sm) - + space_map_alloc_delta(msp->ms_sm); + + /* + * Account for future allocations since we would have already + * deducted that space from the ms_freetree. + */ + for (int t = 0; t < TXG_CONCURRENT_STATES; t++) { + allocated += + range_tree_space(msp->ms_alloctree[(txg + t) & TXG_MASK]); + } + freed = range_tree_space(msp->ms_freetree[TXG_CLEAN(txg) & TXG_MASK]); + + msp_free_space = range_tree_space(msp->ms_tree) + allocated + + msp->ms_deferspace + freed; + + VERIFY3U(sm_free_space, ==, msp_free_space); +} + +/* + * ========================================================================== + * Metaslab groups + * ========================================================================== + */ +/* * 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 or has a fragmentation value that is @@ -1078,7 +1150,7 @@ static range_tree_ops_t metaslab_rt_ops /* * ========================================================================== - * Metaslab block operations + * Common allocator routines * ========================================================================== */ @@ -1097,31 +1169,22 @@ metaslab_block_maxsize(metaslab_t *msp) return (rs->rs_end - rs->rs_start); } -uint64_t -metaslab_block_alloc(metaslab_t *msp, uint64_t size) +static range_seg_t * +metaslab_block_find(avl_tree_t *t, uint64_t start, uint64_t size) { - uint64_t start; - range_tree_t *rt = msp->ms_tree; - - VERIFY(!msp->ms_condensing); + range_seg_t *rs, rsearch; + avl_index_t where; - start = msp->ms_ops->msop_alloc(msp, size); - if (start != -1ULL) { - vdev_t *vd = msp->ms_group->mg_vd; + rsearch.rs_start = start; + rsearch.rs_end = start + size; - VERIFY0(P2PHASE(start, 1ULL << vd->vdev_ashift)); - VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift)); - VERIFY3U(range_tree_space(rt) - size, <=, msp->ms_size); - range_tree_remove(rt, start, size); + rs = avl_find(t, &rsearch, &where); + if (rs == NULL) { + rs = avl_nearest(t, where, AVL_AFTER); } - return (start); -} -/* - * ========================================================================== - * Common allocator routines - * ========================================================================== - */ + return (rs); +} /* * This is a helper function that can be used by the allocator to find @@ -1132,15 +1195,7 @@ static uint64_t metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size, uint64_t align) { - range_seg_t *rs, rsearch; - avl_index_t where; - - rsearch.rs_start = *cursor; - rsearch.rs_end = *cursor + size; - - rs = avl_find(t, &rsearch, &where); - if (rs == NULL) - rs = avl_nearest(t, where, AVL_AFTER); + range_seg_t *rs = metaslab_block_find(t, *cursor, size); while (rs != NULL) { uint64_t offset = P2ROUNDUP(rs->rs_start, align); @@ -1365,6 +1420,7 @@ int metaslab_load(metaslab_t *msp) { int error = 0; + boolean_t success = B_FALSE; ASSERT(MUTEX_HELD(&msp->ms_lock)); ASSERT(!msp->ms_loaded); @@ -1382,14 +1438,18 @@ metaslab_load(metaslab_t *msp) else range_tree_add(msp->ms_tree, msp->ms_start, msp->ms_size); - msp->ms_loaded = (error == 0); + success = (error == 0); msp->ms_loading = B_FALSE; - if (msp->ms_loaded) { + if (success) { + ASSERT3P(msp->ms_group, !=, NULL); + msp->ms_loaded = B_TRUE; + for (int t = 0; t < TXG_DEFER_SIZE; t++) { range_tree_walk(msp->ms_defertree[t], range_tree_remove, msp->ms_tree); } + msp->ms_max_size = metaslab_block_maxsize(msp); } cv_broadcast(&msp->ms_load_cv); return (error); @@ -1402,6 +1462,7 @@ metaslab_unload(metaslab_t *msp) range_tree_vacate(msp->ms_tree, NULL, NULL); msp->ms_loaded = B_FALSE; msp->ms_weight &= ~METASLAB_ACTIVE_MASK; + msp->ms_max_size = 0; } int @@ -1446,21 +1507,23 @@ metaslab_init(metaslab_group_t *mg, uint ms->ms_tree = range_tree_create(&metaslab_rt_ops, ms, &ms->ms_lock); metaslab_group_add(mg, ms); - ms->ms_fragmentation = metaslab_fragmentation(ms); - ms->ms_ops = mg->mg_class->mc_ops; + metaslab_set_fragmentation(ms); /* * If we're opening an existing pool (txg == 0) or creating * a new one (txg == TXG_INITIAL), all space is available now. * If we're adding space to an existing pool, the new space * does not become available until after this txg has synced. + * The metaslab's weight will also be initialized when we sync + * out this txg. This ensures that we don't attempt to allocate + * from it before we have initialized it completely. */ if (txg <= TXG_INITIAL) metaslab_sync_done(ms, 0); /* * If metaslab_debug_load is set and we're initializing a metaslab - * that has an allocated space_map object then load the its space + * that has an allocated space map object then load the its space * map so that can verify frees. */ if (metaslab_debug_load && ms->ms_sm != NULL) { @@ -1487,7 +1550,6 @@ metaslab_fini(metaslab_t *msp) metaslab_group_remove(mg, msp); mutex_enter(&msp->ms_lock); - VERIFY(msp->ms_group == NULL); vdev_space_update(mg->mg_vd, -space_map_allocated(msp->ms_sm), 0, -msp->ms_size); @@ -1560,8 +1622,8 @@ int zfs_frag_table[FRAGMENTATION_TABLE_S * not support this metric. Otherwise, the return value should be in the * range [0, 100]. */ -static uint64_t -metaslab_fragmentation(metaslab_t *msp) +static void +metaslab_set_fragmentation(metaslab_t *msp) { spa_t *spa = msp->ms_group->mg_vd->vdev_spa; uint64_t fragmentation = 0; @@ -1569,18 +1631,22 @@ metaslab_fragmentation(metaslab_t *msp) boolean_t feature_enabled = spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM); - if (!feature_enabled) - return (ZFS_FRAG_INVALID); + if (!feature_enabled) { + msp->ms_fragmentation = ZFS_FRAG_INVALID; + return; + } /* * A null space map means that the entire metaslab is free * and thus is not fragmented. */ - if (msp->ms_sm == NULL) - return (0); + if (msp->ms_sm == NULL) { + msp->ms_fragmentation = 0; + return; + } /* - * If this metaslab's space_map has not been upgraded, flag it + * If this metaslab's space map has not been upgraded, flag it * so that we upgrade next time we encounter it. */ if (msp->ms_sm->sm_dbuf->db_size != sizeof (space_map_phys_t)) { @@ -1593,12 +1659,14 @@ metaslab_fragmentation(metaslab_t *msp) spa_dbgmsg(spa, "txg %llu, requesting force condense: " "msp %p, vd %p", txg, msp, vd); } - return (ZFS_FRAG_INVALID); + msp->ms_fragmentation = ZFS_FRAG_INVALID; + return; } for (int i = 0; i < SPACE_MAP_HISTOGRAM_SIZE; i++) { uint64_t space = 0; uint8_t shift = msp->ms_sm->sm_shift; + int idx = MIN(shift - SPA_MINBLOCKSHIFT + i, FRAGMENTATION_TABLE_SIZE - 1); @@ -1615,7 +1683,8 @@ metaslab_fragmentation(metaslab_t *msp) if (total > 0) fragmentation /= total; ASSERT3U(fragmentation, <=, 100); - return (fragmentation); + + msp->ms_fragmentation = fragmentation; } /* @@ -1624,30 +1693,20 @@ metaslab_fragmentation(metaslab_t *msp) * the LBA range, and whether the metaslab is loaded. */ static uint64_t -metaslab_weight(metaslab_t *msp) +metaslab_space_weight(metaslab_t *msp) { metaslab_group_t *mg = msp->ms_group; vdev_t *vd = mg->mg_vd; uint64_t weight, space; ASSERT(MUTEX_HELD(&msp->ms_lock)); - - /* - * This vdev is in the process of being removed so there is nothing - * for us to do here. - */ - if (vd->vdev_removing) { - ASSERT0(space_map_allocated(msp->ms_sm)); - ASSERT0(vd->vdev_ms_shift); - return (0); - } + ASSERT(!vd->vdev_removing); /* * The baseline weight is the metaslab's free space. */ space = msp->ms_size - space_map_allocated(msp->ms_sm); - msp->ms_fragmentation = metaslab_fragmentation(msp); if (metaslab_fragmentation_factor_enabled && msp->ms_fragmentation != ZFS_FRAG_INVALID) { /* @@ -1696,6 +1755,210 @@ metaslab_weight(metaslab_t *msp) weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK); } + WEIGHT_SET_SPACEBASED(weight); + return (weight); +} + +/* + * Return the weight of the specified metaslab, according to the segment-based + * weighting algorithm. The metaslab must be loaded. This function can + * be called within a sync pass since it relies only on the metaslab's + * range tree which is always accurate when the metaslab is loaded. + */ +static uint64_t +metaslab_weight_from_range_tree(metaslab_t *msp) +{ + uint64_t weight = 0; + uint32_t segments = 0; + + ASSERT(msp->ms_loaded); + + for (int i = RANGE_TREE_HISTOGRAM_SIZE - 1; i >= SPA_MINBLOCKSHIFT; + i--) { + uint8_t shift = msp->ms_group->mg_vd->vdev_ashift; + int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1; + + segments <<= 1; + segments += msp->ms_tree->rt_histogram[i]; + + /* + * The range tree provides more precision than the space map + * and must be downgraded so that all values fit within the + * space map's histogram. This allows us to compare loaded + * vs. unloaded metaslabs to determine which metaslab is + * considered "best". + */ + if (i > max_idx) + continue; + + if (segments != 0) { + WEIGHT_SET_COUNT(weight, segments); + WEIGHT_SET_INDEX(weight, i); + WEIGHT_SET_ACTIVE(weight, 0); + break; + } + } + return (weight); +} + +/* + * Calculate the weight based on the on-disk histogram. This should only + * be called after a sync pass has completely finished since the on-disk + * information is updated in metaslab_sync(). + */ +static uint64_t +metaslab_weight_from_spacemap(metaslab_t *msp) +{ + uint64_t weight = 0; + + for (int i = SPACE_MAP_HISTOGRAM_SIZE - 1; i >= 0; i--) { + if (msp->ms_sm->sm_phys->smp_histogram[i] != 0) { + WEIGHT_SET_COUNT(weight, + msp->ms_sm->sm_phys->smp_histogram[i]); + WEIGHT_SET_INDEX(weight, i + + msp->ms_sm->sm_shift); + WEIGHT_SET_ACTIVE(weight, 0); + break; + } + } + return (weight); +} + +/* + * Compute a segment-based weight for the specified metaslab. The weight + * is determined by highest bucket in the histogram. The information + * for the highest bucket is encoded into the weight value. + */ +static uint64_t +metaslab_segment_weight(metaslab_t *msp) +{ + metaslab_group_t *mg = msp->ms_group; + uint64_t weight = 0; + uint8_t shift = mg->mg_vd->vdev_ashift; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + /* + * The metaslab is completely free. + */ + if (space_map_allocated(msp->ms_sm) == 0) { + int idx = highbit64(msp->ms_size) - 1; + int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1; + + if (idx < max_idx) { + WEIGHT_SET_COUNT(weight, 1ULL); + WEIGHT_SET_INDEX(weight, idx); + } else { + WEIGHT_SET_COUNT(weight, 1ULL << (idx - max_idx)); + WEIGHT_SET_INDEX(weight, max_idx); + } + WEIGHT_SET_ACTIVE(weight, 0); + ASSERT(!WEIGHT_IS_SPACEBASED(weight)); + + return (weight); + } + + ASSERT3U(msp->ms_sm->sm_dbuf->db_size, ==, sizeof (space_map_phys_t)); + + /* + * If the metaslab is fully allocated then just make the weight 0. + */ + if (space_map_allocated(msp->ms_sm) == msp->ms_size) + return (0); + /* + * If the metaslab is already loaded, then use the range tree to + * determine the weight. Otherwise, we rely on the space map information + * to generate the weight. + */ + if (msp->ms_loaded) { + weight = metaslab_weight_from_range_tree(msp); + } else { + weight = metaslab_weight_from_spacemap(msp); + } + + /* + * If the metaslab was active the last time we calculated its weight + * then keep it active. We want to consume the entire region that + * is associated with this weight. + */ + if (msp->ms_activation_weight != 0 && weight != 0) + WEIGHT_SET_ACTIVE(weight, WEIGHT_GET_ACTIVE(msp->ms_weight)); + return (weight); +} + +/* + * Determine if we should attempt to allocate from this metaslab. If the + * metaslab has a maximum size then we can quickly determine if the desired + * allocation size can be satisfied. Otherwise, if we're using segment-based + * weighting then we can determine the maximum allocation that this metaslab + * can accommodate based on the index encoded in the weight. If we're using + * space-based weights then rely on the entire weight (excluding the weight + * type bit). + */ +boolean_t +metaslab_should_allocate(metaslab_t *msp, uint64_t asize) +{ + boolean_t should_allocate; + + if (msp->ms_max_size != 0) + return (msp->ms_max_size >= asize); + + if (!WEIGHT_IS_SPACEBASED(msp->ms_weight)) { + /* + * The metaslab segment weight indicates segments in the + * range [2^i, 2^(i+1)), where i is the index in the weight. + * Since the asize might be in the middle of the range, we + * should attempt the allocation if asize < 2^(i+1). + */ + should_allocate = (asize < + 1ULL << (WEIGHT_GET_INDEX(msp->ms_weight) + 1)); + } else { + should_allocate = (asize <= + (msp->ms_weight & ~METASLAB_WEIGHT_TYPE)); + } + return (should_allocate); +} + +static uint64_t +metaslab_weight(metaslab_t *msp) +{ + vdev_t *vd = msp->ms_group->mg_vd; + spa_t *spa = vd->vdev_spa; + uint64_t weight; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + + /* + * This vdev is in the process of being removed so there is nothing + * for us to do here. + */ + if (vd->vdev_removing) { + ASSERT0(space_map_allocated(msp->ms_sm)); + ASSERT0(vd->vdev_ms_shift); + return (0); + } + + metaslab_set_fragmentation(msp); + + /* + * Update the maximum size if the metaslab is loaded. This will + * ensure that we get an accurate maximum size if newly freed space + * has been added back into the free tree. + */ + if (msp->ms_loaded) + msp->ms_max_size = metaslab_block_maxsize(msp); + + /* + * Segment-based weighting requires space map histogram support. + */ + if (zfs_metaslab_segment_weight_enabled && + spa_feature_is_enabled(spa, SPA_FEATURE_SPACEMAP_HISTOGRAM) && + (msp->ms_sm == NULL || msp->ms_sm->sm_dbuf->db_size == + sizeof (space_map_phys_t))) { + weight = metaslab_segment_weight(msp); + } else { + weight = metaslab_space_weight(msp); + } return (weight); } @@ -1714,6 +1977,7 @@ metaslab_activate(metaslab_t *msp, uint6 } } + msp->ms_activation_weight = msp->ms_weight; metaslab_group_sort(msp->ms_group, msp, msp->ms_weight | activation_weight); } @@ -1724,18 +1988,56 @@ metaslab_activate(metaslab_t *msp, uint6 } static void -metaslab_passivate(metaslab_t *msp, uint64_t size) +metaslab_passivate(metaslab_t *msp, uint64_t weight) { + uint64_t size = weight & ~METASLAB_WEIGHT_TYPE; + /* * If size < SPA_MINBLOCKSIZE, then we will not allocate from * this metaslab again. In that case, it had better be empty, * or we would be leaving space on the table. */ - ASSERT(size >= SPA_MINBLOCKSIZE || range_tree_space(msp->ms_tree) == 0); - metaslab_group_sort(msp->ms_group, msp, MIN(msp->ms_weight, size)); + ASSERT(size >= SPA_MINBLOCKSIZE || + range_tree_space(msp->ms_tree) == 0); + ASSERT0(weight & METASLAB_ACTIVE_MASK); + + msp->ms_activation_weight = 0; + metaslab_group_sort(msp->ms_group, msp, weight); ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0); } +/* + * Segment-based metaslabs are activated once and remain active until + * we either fail an allocation attempt (similar to space-based metaslabs) + * or have exhausted the free space in zfs_metaslab_switch_threshold + * buckets since the metaslab was activated. This function checks to see + * if we've exhaused the zfs_metaslab_switch_threshold buckets in the + * metaslab and passivates it proactively. This will allow us to select a + * metaslabs with larger contiguous region if any remaining within this + * metaslab group. If we're in sync pass > 1, then we continue using this + * metaslab so that we don't dirty more block and cause more sync passes. + */ +void +metaslab_segment_may_passivate(metaslab_t *msp) +{ + spa_t *spa = msp->ms_group->mg_vd->vdev_spa; + + if (WEIGHT_IS_SPACEBASED(msp->ms_weight) || spa_sync_pass(spa) > 1) + return; + + /* + * Since we are in the middle of a sync pass, the most accurate + * information that is accessible to us is the in-core range tree + * histogram; calculate the new weight based on that information. + */ + uint64_t weight = metaslab_weight_from_range_tree(msp); + int activation_idx = WEIGHT_GET_INDEX(msp->ms_activation_weight); + int current_idx = WEIGHT_GET_INDEX(weight); + + if (current_idx <= activation_idx - zfs_metaslab_switch_threshold) + metaslab_passivate(msp, weight); +} + static void metaslab_preload(void *arg) { @@ -1748,11 +2050,7 @@ metaslab_preload(void *arg) metaslab_load_wait(msp); if (!msp->ms_loaded) (void) metaslab_load(msp); - - /* - * Set the ms_access_txg value so that we don't unload it right away. - */ - msp->ms_access_txg = spa_syncing_txg(spa) + metaslab_unload_delay + 1; + msp->ms_selected_txg = spa_syncing_txg(spa); mutex_exit(&msp->ms_lock); } @@ -1773,10 +2071,7 @@ metaslab_group_preload(metaslab_group_t /* * Load the next potential metaslabs */ - msp = avl_first(t); - while (msp != NULL) { - metaslab_t *msp_next = AVL_NEXT(t, msp); - + for (msp = avl_first(t); msp != NULL; msp = AVL_NEXT(t, msp)) { /* * We preload only the maximum number of metaslabs specified * by metaslab_preload_limit. If a metaslab is being forced @@ -1784,27 +2079,11 @@ metaslab_group_preload(metaslab_group_t * that force condensing happens in the next txg. */ if (++m > metaslab_preload_limit && !msp->ms_condense_wanted) { - msp = msp_next; continue; } - /* - * We must drop the metaslab group lock here to preserve - * lock ordering with the ms_lock (when grabbing both - * the mg_lock and the ms_lock, the ms_lock must be taken - * first). As a result, it is possible that the ordering - * of the metaslabs within the avl tree may change before - * we reacquire the lock. The metaslab cannot be removed from - * the tree while we're in syncing context so it is safe to - * drop the mg_lock here. If the metaslabs are reordered - * nothing will break -- we just may end up loading a - * less than optimal one. - */ - mutex_exit(&mg->mg_lock); VERIFY(taskq_dispatch(mg->mg_taskq, metaslab_preload, msp, TQ_SLEEP) != 0); - mutex_enter(&mg->mg_lock); - msp = msp_next; } mutex_exit(&mg->mg_lock); } @@ -1953,7 +2232,7 @@ metaslab_condense(metaslab_t *msp, uint6 mutex_enter(&msp->ms_lock); /* - * While we would ideally like to create a space_map representation + * While we would ideally like to create a space map representation * that consists only of allocation records, doing so can be * prohibitively expensive because the in-core free tree can be * large, and therefore computationally expensive to subtract @@ -2016,7 +2295,7 @@ metaslab_sync(metaslab_t *msp, uint64_t * metaslab_sync() is the metaslab's ms_tree. No other thread can * be modifying this txg's alloctree, freetree, freed_tree, or * space_map_phys_t. Therefore, we only hold ms_lock to satify - * space_map ASSERTs. We drop it whenever we call into the DMU, + * space map ASSERTs. We drop it whenever we call into the DMU, * because the DMU can call down to us (e.g. via zio_free()) at * any time. */ @@ -2038,7 +2317,7 @@ metaslab_sync(metaslab_t *msp, uint64_t mutex_enter(&msp->ms_lock); /* - * Note: metaslab_condense() clears the space_map's histogram. + * Note: metaslab_condense() clears the space map's histogram. * Therefore we must verify and remove this histogram before * condensing. */ @@ -2063,16 +2342,38 @@ metaslab_sync(metaslab_t *msp, uint64_t */ space_map_histogram_clear(msp->ms_sm); space_map_histogram_add(msp->ms_sm, msp->ms_tree, tx); - } else { + + /* + * Since we've cleared the histogram we need to add back + * any free space that has already been processed, plus + * any deferred space. This allows the on-disk histogram + * to accurately reflect all free space even if some space + * is not yet available for allocation (i.e. deferred). + */ + space_map_histogram_add(msp->ms_sm, *freed_tree, tx); + /* - * Since the space map is not loaded we simply update the - * exisiting histogram with what was freed in this txg. This - * means that the on-disk histogram may not have an accurate - * view of the free space but it's close enough to allow - * us to make allocation decisions. + * Add back any deferred free space that has not been + * added back into the in-core free tree yet. This will + * ensure that we don't end up with a space map histogram + * that is completely empty unless the metaslab is fully + * allocated. */ - space_map_histogram_add(msp->ms_sm, *freetree, tx); + for (int t = 0; t < TXG_DEFER_SIZE; t++) { + space_map_histogram_add(msp->ms_sm, + msp->ms_defertree[t], tx); + } } + + /* + * Always add the free space from this sync pass to the space + * map histogram. We want to make sure that the on-disk histogram + * accounts for all free space. If the space map is not loaded, + * then we will lose some accuracy but will correct it the next + * time we load the space map. + */ + space_map_histogram_add(msp->ms_sm, *freetree, tx); + metaslab_group_histogram_add(mg, msp); metaslab_group_histogram_verify(mg); metaslab_class_histogram_verify(mg->mg_class); @@ -2091,6 +2392,7 @@ metaslab_sync(metaslab_t *msp, uint64_t range_tree_vacate(alloctree, NULL, NULL); ASSERT0(range_tree_space(msp->ms_alloctree[txg & TXG_MASK])); + ASSERT0(range_tree_space(msp->ms_alloctree[TXG_CLEAN(txg) & TXG_MASK])); ASSERT0(range_tree_space(msp->ms_freetree[txg & TXG_MASK])); mutex_exit(&msp->ms_lock); @@ -2112,9 +2414,11 @@ metaslab_sync_done(metaslab_t *msp, uint { metaslab_group_t *mg = msp->ms_group; vdev_t *vd = mg->mg_vd; + spa_t *spa = vd->vdev_spa; range_tree_t **freed_tree; range_tree_t **defer_tree; int64_t alloc_delta, defer_delta; + boolean_t defer_allowed = B_TRUE; ASSERT(!vd->vdev_ishole); @@ -2149,9 +2453,20 @@ metaslab_sync_done(metaslab_t *msp, uint freed_tree = &msp->ms_freetree[TXG_CLEAN(txg) & TXG_MASK]; defer_tree = &msp->ms_defertree[txg % TXG_DEFER_SIZE]; + uint64_t free_space = metaslab_class_get_space(spa_normal_class(spa)) - + metaslab_class_get_alloc(spa_normal_class(spa)); + if (free_space <= spa_get_slop_space(spa)) { + defer_allowed = B_FALSE; + } + + defer_delta = 0; alloc_delta = space_map_alloc_delta(msp->ms_sm); - defer_delta = range_tree_space(*freed_tree) - - range_tree_space(*defer_tree); + if (defer_allowed) { + defer_delta = range_tree_space(*freed_tree) - + range_tree_space(*defer_tree); + } else { + defer_delta -= range_tree_space(*defer_tree); + } vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0); @@ -2172,7 +2487,12 @@ metaslab_sync_done(metaslab_t *msp, uint */ range_tree_vacate(*defer_tree, msp->ms_loaded ? range_tree_add : NULL, msp->ms_tree); - range_tree_swap(freed_tree, defer_tree); + if (defer_allowed) { + range_tree_swap(freed_tree, defer_tree); + } else { + range_tree_vacate(*freed_tree, + msp->ms_loaded ? range_tree_add : NULL, msp->ms_tree); + } space_map_update(msp->ms_sm); @@ -2187,7 +2507,18 @@ metaslab_sync_done(metaslab_t *msp, uint vdev_dirty(vd, VDD_METASLAB, msp, txg + 1); } - if (msp->ms_loaded && msp->ms_access_txg < txg) { + /* + * Calculate the new weights before unloading any metaslabs. + * This will give us the most accurate weighting. + */ + metaslab_group_sort(mg, msp, metaslab_weight(msp)); + + /* + * If the metaslab is loaded and we've not tried to load or allocate + * from it in 'metaslab_unload_delay' txgs, then unload it. + */ + if (msp->ms_loaded && + msp->ms_selected_txg + metaslab_unload_delay < txg) { for (int t = 1; t < TXG_CONCURRENT_STATES; t++) { VERIFY0(range_tree_space( msp->ms_alloctree[(txg + t) & TXG_MASK])); @@ -2197,7 +2528,6 @@ metaslab_sync_done(metaslab_t *msp, uint metaslab_unload(msp); } - metaslab_group_sort(mg, msp, metaslab_weight(msp)); mutex_exit(&msp->ms_lock); } @@ -2232,6 +2562,113 @@ metaslab_distance(metaslab_t *msp, dva_t /* * ========================================================================== *** DIFF OUTPUT TRUNCATED AT 1000 LINES *** _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
