Date: Wed, 27 Feb 2013 14:45:24 +0000 (UTC) From: Martin Matuska <mm@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r247398 - in head: cddl/contrib/opensolaris/cmd/zdb sys/cddl/contrib/opensolaris/uts/common/fs/zfs sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys Message-ID: <201302271445.r1REjOEE087781@svn.freebsd.org>
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Author: mm Date: Wed Feb 27 14:45:23 2013 New Revision: 247398 URL: http://svnweb.freebsd.org/changeset/base/247398 Log: MFV 247176, 247178, 247315: Import metaslab_sync() speedup from vendor (illumos). Illumos ZFS issues: 3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread 3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not condensing) 3578 transferring the freed map to the defer map should be constant time 3579 ztest trips assertion in metaslab_weight() References: https://www.illumos.org/issues/3552 https://www.illumos.org/issues/3564 https://www.illumos.org/issues/3578 https://www.illumos.org/issues/3579 MFC after: 2 weeks Modified: head/cddl/contrib/opensolaris/cmd/zdb/zdb.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/space_map.c head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/space_map.h head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Directory Properties: head/cddl/contrib/opensolaris/ (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 Wed Feb 27 11:42:28 2013 (r247397) +++ head/cddl/contrib/opensolaris/cmd/zdb/zdb.c Wed Feb 27 14:45:23 2013 (r247398) @@ -545,7 +545,7 @@ static void dump_metaslab_stats(metaslab_t *msp) { char maxbuf[32]; - space_map_t *sm = &msp->ms_map; + space_map_t *sm = msp->ms_map; avl_tree_t *t = sm->sm_pp_root; int free_pct = sm->sm_space * 100 / sm->sm_size; @@ -561,7 +561,7 @@ dump_metaslab(metaslab_t *msp) { vdev_t *vd = msp->ms_group->mg_vd; spa_t *spa = vd->vdev_spa; - space_map_t *sm = &msp->ms_map; + space_map_t *sm = msp->ms_map; space_map_obj_t *smo = &msp->ms_smo; char freebuf[32]; @@ -2160,11 +2160,11 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb) for (int m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *msp = vd->vdev_ms[m]; mutex_enter(&msp->ms_lock); - space_map_unload(&msp->ms_map); - VERIFY(space_map_load(&msp->ms_map, + space_map_unload(msp->ms_map); + VERIFY(space_map_load(msp->ms_map, &zdb_space_map_ops, SM_ALLOC, &msp->ms_smo, spa->spa_meta_objset) == 0); - msp->ms_map.sm_ppd = vd; + msp->ms_map->sm_ppd = vd; mutex_exit(&msp->ms_lock); } } @@ -2187,7 +2187,7 @@ zdb_leak_fini(spa_t *spa) for (int m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *msp = vd->vdev_ms[m]; mutex_enter(&msp->ms_lock); - space_map_unload(&msp->ms_map); + space_map_unload(msp->ms_map); mutex_exit(&msp->ms_lock); } } Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Wed Feb 27 11:42:28 2013 (r247397) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/metaslab.c Wed Feb 27 14:45:23 2013 (r247398) @@ -48,6 +48,14 @@ uint64_t metaslab_aliquot = 512ULL << 10 uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */ /* + * 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. + * Values should be greater than or equal to 100. + */ +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. @@ -215,9 +223,9 @@ metaslab_compare(const void *x1, const v /* * If the weights are identical, use the offset to force uniqueness. */ - if (m1->ms_map.sm_start < m2->ms_map.sm_start) + if (m1->ms_map->sm_start < m2->ms_map->sm_start) return (-1); - if (m1->ms_map.sm_start > m2->ms_map.sm_start) + if (m1->ms_map->sm_start > m2->ms_map->sm_start) return (1); ASSERT3P(m1, ==, m2); @@ -732,14 +740,15 @@ metaslab_init(metaslab_group_t *mg, spac * addition of new space; and for debugging, it ensures that we'd * data fault on any attempt to use this metaslab before it's ready. */ - space_map_create(&msp->ms_map, start, size, + msp->ms_map = kmem_zalloc(sizeof (space_map_t), KM_SLEEP); + space_map_create(msp->ms_map, start, size, vd->vdev_ashift, &msp->ms_lock); metaslab_group_add(mg, msp); if (metaslab_debug && smo->smo_object != 0) { mutex_enter(&msp->ms_lock); - VERIFY(space_map_load(&msp->ms_map, mg->mg_class->mc_ops, + VERIFY(space_map_load(msp->ms_map, mg->mg_class->mc_ops, SM_FREE, smo, spa_meta_objset(vd->vdev_spa)) == 0); mutex_exit(&msp->ms_lock); } @@ -767,22 +776,27 @@ metaslab_fini(metaslab_t *msp) metaslab_group_t *mg = msp->ms_group; vdev_space_update(mg->mg_vd, - -msp->ms_smo.smo_alloc, 0, -msp->ms_map.sm_size); + -msp->ms_smo.smo_alloc, 0, -msp->ms_map->sm_size); metaslab_group_remove(mg, msp); mutex_enter(&msp->ms_lock); - space_map_unload(&msp->ms_map); - space_map_destroy(&msp->ms_map); + space_map_unload(msp->ms_map); + space_map_destroy(msp->ms_map); + kmem_free(msp->ms_map, sizeof (*msp->ms_map)); for (int t = 0; t < TXG_SIZE; t++) { - space_map_destroy(&msp->ms_allocmap[t]); - space_map_destroy(&msp->ms_freemap[t]); + space_map_destroy(msp->ms_allocmap[t]); + space_map_destroy(msp->ms_freemap[t]); + kmem_free(msp->ms_allocmap[t], sizeof (*msp->ms_allocmap[t])); + kmem_free(msp->ms_freemap[t], sizeof (*msp->ms_freemap[t])); } - for (int t = 0; t < TXG_DEFER_SIZE; t++) - space_map_destroy(&msp->ms_defermap[t]); + for (int t = 0; t < TXG_DEFER_SIZE; t++) { + space_map_destroy(msp->ms_defermap[t]); + kmem_free(msp->ms_defermap[t], sizeof (*msp->ms_defermap[t])); + } ASSERT0(msp->ms_deferspace); @@ -801,7 +815,7 @@ static uint64_t metaslab_weight(metaslab_t *msp) { metaslab_group_t *mg = msp->ms_group; - space_map_t *sm = &msp->ms_map; + space_map_t *sm = msp->ms_map; space_map_obj_t *smo = &msp->ms_smo; vdev_t *vd = mg->mg_vd; uint64_t weight, space; @@ -809,6 +823,16 @@ metaslab_weight(metaslab_t *msp) 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(smo->smo_alloc); + ASSERT0(vd->vdev_ms_shift); + return (0); + } + + /* * The baseline weight is the metaslab's free space. */ space = sm->sm_size - smo->smo_alloc; @@ -861,7 +885,7 @@ metaslab_prefetch(metaslab_group_t *mg) * Prefetch the next potential metaslabs */ for (msp = avl_first(t), m = 0; msp; msp = AVL_NEXT(t, msp), m++) { - space_map_t *sm = &msp->ms_map; + space_map_t *sm = msp->ms_map; space_map_obj_t *smo = &msp->ms_smo; /* If we have reached our prefetch limit then we're done */ @@ -882,7 +906,7 @@ static int metaslab_activate(metaslab_t *msp, uint64_t activation_weight) { metaslab_group_t *mg = msp->ms_group; - space_map_t *sm = &msp->ms_map; + space_map_t *sm = msp->ms_map; space_map_ops_t *sm_ops = msp->ms_group->mg_class->mc_ops; ASSERT(MUTEX_HELD(&msp->ms_lock)); @@ -899,7 +923,7 @@ metaslab_activate(metaslab_t *msp, uint6 return (error); } for (int t = 0; t < TXG_DEFER_SIZE; t++) - space_map_walk(&msp->ms_defermap[t], + space_map_walk(msp->ms_defermap[t], space_map_claim, sm); } @@ -930,12 +954,158 @@ metaslab_passivate(metaslab_t *msp, uint * this metaslab again. In that case, it had better be empty, * or we would be leaving space on the table. */ - ASSERT(size >= SPA_MINBLOCKSIZE || msp->ms_map.sm_space == 0); + ASSERT(size >= SPA_MINBLOCKSIZE || msp->ms_map->sm_space == 0); metaslab_group_sort(msp->ms_group, msp, MIN(msp->ms_weight, size)); ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0); } /* + * Determine if the in-core space map representation can be condensed on-disk. + * We would like to use the following criteria to make our decision: + * + * 1. The size of the space map object should not dramatically increase as a + * result of writing out our in-core free map. + * + * 2. The minimal on-disk space map representation is zfs_condense_pct/100 + * times the size than the in-core representation (i.e. zfs_condense_pct = 110 + * and in-core = 1MB, minimal = 1.1.MB). + * + * Checking the first condition is tricky since we don't want to walk + * the entire AVL tree calculating the estimated on-disk size. Instead we + * use the size-ordered AVL tree in the space map and calculate the + * size required for the largest segment in our in-core free map. If the + * size required to represent that segment on disk is larger than the space + * map object then we avoid condensing this map. + * + * To determine the second criterion we use a best-case estimate and assume + * each segment can be represented on-disk as a single 64-bit entry. We refer + * to this best-case estimate as the space map's minimal form. + */ +static boolean_t +metaslab_should_condense(metaslab_t *msp) +{ + space_map_t *sm = msp->ms_map; + space_map_obj_t *smo = &msp->ms_smo_syncing; + space_seg_t *ss; + uint64_t size, entries, segsz; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + ASSERT(sm->sm_loaded); + + /* + * Use the sm_pp_root AVL tree, which is ordered by size, to obtain + * the largest segment in the in-core free map. If the tree is + * empty then we should condense the map. + */ + ss = avl_last(sm->sm_pp_root); + if (ss == NULL) + return (B_TRUE); + + /* + * Calculate the number of 64-bit entries this segment would + * require when written to disk. If this single segment would be + * larger on-disk than the entire current on-disk structure, then + * clearly condensing will increase the on-disk structure size. + */ + size = (ss->ss_end - ss->ss_start) >> sm->sm_shift; + entries = size / (MIN(size, SM_RUN_MAX)); + segsz = entries * sizeof (uint64_t); + + return (segsz <= smo->smo_objsize && + smo->smo_objsize >= (zfs_condense_pct * + sizeof (uint64_t) * avl_numnodes(&sm->sm_root)) / 100); +} + +/* + * Condense the on-disk space map representation to its minimized form. + * The minimized form consists of a small number of allocations followed by + * the in-core free map. + */ +static void +metaslab_condense(metaslab_t *msp, uint64_t txg, dmu_tx_t *tx) +{ + spa_t *spa = msp->ms_group->mg_vd->vdev_spa; + space_map_t *freemap = msp->ms_freemap[txg & TXG_MASK]; + space_map_t condense_map; + space_map_t *sm = msp->ms_map; + objset_t *mos = spa_meta_objset(spa); + space_map_obj_t *smo = &msp->ms_smo_syncing; + + ASSERT(MUTEX_HELD(&msp->ms_lock)); + ASSERT3U(spa_sync_pass(spa), ==, 1); + ASSERT(sm->sm_loaded); + + spa_dbgmsg(spa, "condensing: txg %llu, msp[%llu] %p, " + "smo size %llu, segments %lu", txg, + (msp->ms_map->sm_start / msp->ms_map->sm_size), msp, + smo->smo_objsize, avl_numnodes(&sm->sm_root)); + + /* + * Create an map that is a 100% allocated map. We remove segments + * that have been freed in this txg, any deferred frees that exist, + * and any allocation in the future. Removing segments should be + * a relatively inexpensive operation since we expect these maps to + * a small number of nodes. + */ + space_map_create(&condense_map, sm->sm_start, sm->sm_size, + sm->sm_shift, sm->sm_lock); + space_map_add(&condense_map, condense_map.sm_start, + condense_map.sm_size); + + /* + * Remove what's been freed in this txg from the condense_map. + * Since we're in sync_pass 1, we know that all the frees from + * this txg are in the freemap. + */ + space_map_walk(freemap, space_map_remove, &condense_map); + + for (int t = 0; t < TXG_DEFER_SIZE; t++) + space_map_walk(msp->ms_defermap[t], + space_map_remove, &condense_map); + + for (int t = 1; t < TXG_CONCURRENT_STATES; t++) + space_map_walk(msp->ms_allocmap[(txg + t) & TXG_MASK], + space_map_remove, &condense_map); + + /* + * We're about to drop the metaslab's lock thus allowing + * other consumers to change it's content. Set the + * space_map's sm_condensing flag to ensure that + * allocations on this metaslab do not occur while we're + * in the middle of committing it to disk. This is only critical + * for the ms_map as all other space_maps use per txg + * views of their content. + */ + sm->sm_condensing = B_TRUE; + + mutex_exit(&msp->ms_lock); + space_map_truncate(smo, mos, tx); + mutex_enter(&msp->ms_lock); + + /* + * 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 map can be + * large, and therefore computationally expensive to subtract + * from the condense_map. Instead we sync out two maps, a cheap + * allocation only map followed by the in-core free map. While not + * optimal, this is typically close to optimal, and much cheaper to + * compute. + */ + space_map_sync(&condense_map, SM_ALLOC, smo, mos, tx); + space_map_vacate(&condense_map, NULL, NULL); + space_map_destroy(&condense_map); + + space_map_sync(sm, SM_FREE, smo, mos, tx); + sm->sm_condensing = B_FALSE; + + spa_dbgmsg(spa, "condensed: txg %llu, msp[%llu] %p, " + "smo size %llu", txg, + (msp->ms_map->sm_start / msp->ms_map->sm_size), msp, + smo->smo_objsize); +} + +/* * Write a metaslab to disk in the context of the specified transaction group. */ void @@ -944,17 +1114,29 @@ metaslab_sync(metaslab_t *msp, uint64_t vdev_t *vd = msp->ms_group->mg_vd; spa_t *spa = vd->vdev_spa; objset_t *mos = spa_meta_objset(spa); - space_map_t *allocmap = &msp->ms_allocmap[txg & TXG_MASK]; - space_map_t *freemap = &msp->ms_freemap[txg & TXG_MASK]; - space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; - space_map_t *sm = &msp->ms_map; + space_map_t *allocmap = msp->ms_allocmap[txg & TXG_MASK]; + space_map_t **freemap = &msp->ms_freemap[txg & TXG_MASK]; + space_map_t **freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; + space_map_t *sm = msp->ms_map; space_map_obj_t *smo = &msp->ms_smo_syncing; dmu_buf_t *db; dmu_tx_t *tx; ASSERT(!vd->vdev_ishole); - if (allocmap->sm_space == 0 && freemap->sm_space == 0) + /* + * This metaslab has just been added so there's no work to do now. + */ + if (*freemap == NULL) { + ASSERT3P(allocmap, ==, NULL); + return; + } + + ASSERT3P(allocmap, !=, NULL); + ASSERT3P(*freemap, !=, NULL); + ASSERT3P(*freed_map, !=, NULL); + + if (allocmap->sm_space == 0 && (*freemap)->sm_space == 0) return; /* @@ -982,49 +1164,36 @@ metaslab_sync(metaslab_t *msp, uint64_t mutex_enter(&msp->ms_lock); - space_map_walk(freemap, space_map_add, freed_map); - - if (sm->sm_loaded && spa_sync_pass(spa) == 1 && smo->smo_objsize >= - 2 * sizeof (uint64_t) * avl_numnodes(&sm->sm_root)) { - /* - * The in-core space map representation is twice as compact - * as the on-disk one, so it's time to condense the latter - * by generating a pure allocmap from first principles. - * - * This metaslab is 100% allocated, - * minus the content of the in-core map (sm), - * minus what's been freed this txg (freed_map), - * minus deferred frees (ms_defermap[]), - * minus allocations from txgs in the future - * (because they haven't been committed yet). - */ - space_map_vacate(allocmap, NULL, NULL); - space_map_vacate(freemap, NULL, NULL); - - space_map_add(allocmap, allocmap->sm_start, allocmap->sm_size); - - space_map_walk(sm, space_map_remove, allocmap); - space_map_walk(freed_map, space_map_remove, allocmap); - - for (int t = 0; t < TXG_DEFER_SIZE; t++) - space_map_walk(&msp->ms_defermap[t], - space_map_remove, allocmap); + if (sm->sm_loaded && spa_sync_pass(spa) == 1 && + metaslab_should_condense(msp)) { + metaslab_condense(msp, txg, tx); + } else { + space_map_sync(allocmap, SM_ALLOC, smo, mos, tx); + space_map_sync(*freemap, SM_FREE, smo, mos, tx); + } - for (int t = 1; t < TXG_CONCURRENT_STATES; t++) - space_map_walk(&msp->ms_allocmap[(txg + t) & TXG_MASK], - space_map_remove, allocmap); + space_map_vacate(allocmap, NULL, NULL); - mutex_exit(&msp->ms_lock); - space_map_truncate(smo, mos, tx); - mutex_enter(&msp->ms_lock); + /* + * For sync pass 1, we avoid walking the entire space map and + * instead will just swap the pointers for freemap and + * freed_map. We can safely do this since the freed_map is + * guaranteed to be empty on the initial pass. + */ + if (spa_sync_pass(spa) == 1) { + ASSERT0((*freed_map)->sm_space); + ASSERT0(avl_numnodes(&(*freed_map)->sm_root)); + space_map_swap(freemap, freed_map); + } else { + space_map_vacate(*freemap, space_map_add, *freed_map); } - space_map_sync(allocmap, SM_ALLOC, smo, mos, tx); - space_map_sync(freemap, SM_FREE, smo, mos, tx); + ASSERT0(msp->ms_allocmap[txg & TXG_MASK]->sm_space); + ASSERT0(msp->ms_freemap[txg & TXG_MASK]->sm_space); mutex_exit(&msp->ms_lock); - VERIFY(0 == dmu_bonus_hold(mos, smo->smo_object, FTAG, &db)); + VERIFY0(dmu_bonus_hold(mos, smo->smo_object, FTAG, &db)); dmu_buf_will_dirty(db, tx); ASSERT3U(db->db_size, >=, sizeof (*smo)); bcopy(smo, db->db_data, sizeof (*smo)); @@ -1042,9 +1211,9 @@ metaslab_sync_done(metaslab_t *msp, uint { space_map_obj_t *smo = &msp->ms_smo; space_map_obj_t *smosync = &msp->ms_smo_syncing; - space_map_t *sm = &msp->ms_map; - space_map_t *freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; - space_map_t *defer_map = &msp->ms_defermap[txg % TXG_DEFER_SIZE]; + space_map_t *sm = msp->ms_map; + space_map_t **freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; + space_map_t **defer_map = &msp->ms_defermap[txg % TXG_DEFER_SIZE]; metaslab_group_t *mg = msp->ms_group; vdev_t *vd = mg->mg_vd; int64_t alloc_delta, defer_delta; @@ -1055,40 +1224,57 @@ metaslab_sync_done(metaslab_t *msp, uint /* * If this metaslab is just becoming available, initialize its - * allocmaps and freemaps and add its capacity to the vdev. + * allocmaps, freemaps, and defermap and add its capacity to the vdev. */ - if (freed_map->sm_size == 0) { + if (*freed_map == NULL) { + ASSERT(*defer_map == NULL); for (int t = 0; t < TXG_SIZE; t++) { - space_map_create(&msp->ms_allocmap[t], sm->sm_start, + msp->ms_allocmap[t] = kmem_zalloc(sizeof (space_map_t), + KM_SLEEP); + space_map_create(msp->ms_allocmap[t], sm->sm_start, sm->sm_size, sm->sm_shift, sm->sm_lock); - space_map_create(&msp->ms_freemap[t], sm->sm_start, + msp->ms_freemap[t] = kmem_zalloc(sizeof (space_map_t), + KM_SLEEP); + space_map_create(msp->ms_freemap[t], sm->sm_start, sm->sm_size, sm->sm_shift, sm->sm_lock); } - for (int t = 0; t < TXG_DEFER_SIZE; t++) - space_map_create(&msp->ms_defermap[t], sm->sm_start, + for (int t = 0; t < TXG_DEFER_SIZE; t++) { + msp->ms_defermap[t] = kmem_zalloc(sizeof (space_map_t), + KM_SLEEP); + space_map_create(msp->ms_defermap[t], sm->sm_start, sm->sm_size, sm->sm_shift, sm->sm_lock); + } + + freed_map = &msp->ms_freemap[TXG_CLEAN(txg) & TXG_MASK]; + defer_map = &msp->ms_defermap[txg % TXG_DEFER_SIZE]; vdev_space_update(vd, 0, 0, sm->sm_size); } alloc_delta = smosync->smo_alloc - smo->smo_alloc; - defer_delta = freed_map->sm_space - defer_map->sm_space; + defer_delta = (*freed_map)->sm_space - (*defer_map)->sm_space; vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0); - ASSERT(msp->ms_allocmap[txg & TXG_MASK].sm_space == 0); - ASSERT(msp->ms_freemap[txg & TXG_MASK].sm_space == 0); + ASSERT(msp->ms_allocmap[txg & TXG_MASK]->sm_space == 0); + ASSERT(msp->ms_freemap[txg & TXG_MASK]->sm_space == 0); /* * If there's a space_map_load() in progress, wait for it to complete * so that we have a consistent view of the in-core space map. - * Then, add defer_map (oldest deferred frees) to this map and - * transfer freed_map (this txg's frees) to defer_map. */ space_map_load_wait(sm); - space_map_vacate(defer_map, sm->sm_loaded ? space_map_free : NULL, sm); - space_map_vacate(freed_map, space_map_add, defer_map); + + /* + * Move the frees from the defer_map to this map (if it's loaded). + * Swap the freed_map and the defer_map -- this is safe to do + * because we've just emptied out the defer_map. + */ + space_map_vacate(*defer_map, sm->sm_loaded ? space_map_free : NULL, sm); + ASSERT0((*defer_map)->sm_space); + ASSERT0(avl_numnodes(&(*defer_map)->sm_root)); + space_map_swap(freed_map, defer_map); *smo = *smosync; @@ -1112,7 +1298,7 @@ metaslab_sync_done(metaslab_t *msp, uint int evictable = 1; for (int t = 1; t < TXG_CONCURRENT_STATES; t++) - if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space) + if (msp->ms_allocmap[(txg + t) & TXG_MASK]->sm_space) evictable = 0; if (evictable && !metaslab_debug) @@ -1137,7 +1323,7 @@ metaslab_sync_reassess(metaslab_group_t for (int m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *msp = vd->vdev_ms[m]; - if (msp->ms_map.sm_start > mg->mg_bonus_area) + if (msp->ms_map->sm_start > mg->mg_bonus_area) break; mutex_enter(&msp->ms_lock); @@ -1158,7 +1344,7 @@ metaslab_distance(metaslab_t *msp, dva_t { uint64_t ms_shift = msp->ms_group->mg_vd->vdev_ms_shift; uint64_t offset = DVA_GET_OFFSET(dva) >> ms_shift; - uint64_t start = msp->ms_map.sm_start >> ms_shift; + uint64_t start = msp->ms_map->sm_start >> ms_shift; if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva)) return (1ULL << 63); @@ -1206,6 +1392,13 @@ metaslab_group_alloc(metaslab_group_t *m mutex_exit(&mg->mg_lock); return (-1ULL); } + + /* + * If the selected metaslab is condensing, skip it. + */ + if (msp->ms_map->sm_condensing) + continue; + was_active = msp->ms_weight & METASLAB_ACTIVE_MASK; if (activation_weight == METASLAB_WEIGHT_PRIMARY) break; @@ -1271,20 +1464,30 @@ metaslab_group_alloc(metaslab_group_t *m continue; } - if ((offset = space_map_alloc(&msp->ms_map, asize)) != -1ULL) + /* + * If this metaslab is currently condensing then pick again as + * we can't manipulate this metaslab until it's committed + * to disk. + */ + if (msp->ms_map->sm_condensing) { + mutex_exit(&msp->ms_lock); + continue; + } + + if ((offset = space_map_alloc(msp->ms_map, asize)) != -1ULL) break; atomic_inc_64(&mg->mg_alloc_failures); - metaslab_passivate(msp, space_map_maxsize(&msp->ms_map)); + metaslab_passivate(msp, space_map_maxsize(msp->ms_map)); mutex_exit(&msp->ms_lock); } - if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0) + if (msp->ms_allocmap[txg & TXG_MASK]->sm_space == 0) vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg); - space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, asize); + space_map_add(msp->ms_allocmap[txg & TXG_MASK], offset, asize); mutex_exit(&msp->ms_lock); @@ -1516,13 +1719,13 @@ metaslab_free_dva(spa_t *spa, const dva_ mutex_enter(&msp->ms_lock); if (now) { - space_map_remove(&msp->ms_allocmap[txg & TXG_MASK], + space_map_remove(msp->ms_allocmap[txg & TXG_MASK], offset, size); - space_map_free(&msp->ms_map, offset, size); + space_map_free(msp->ms_map, offset, size); } else { - if (msp->ms_freemap[txg & TXG_MASK].sm_space == 0) + if (msp->ms_freemap[txg & TXG_MASK]->sm_space == 0) vdev_dirty(vd, VDD_METASLAB, msp, txg); - space_map_add(&msp->ms_freemap[txg & TXG_MASK], offset, size); + space_map_add(msp->ms_freemap[txg & TXG_MASK], offset, size); } mutex_exit(&msp->ms_lock); @@ -1557,10 +1760,10 @@ metaslab_claim_dva(spa_t *spa, const dva mutex_enter(&msp->ms_lock); - if ((txg != 0 && spa_writeable(spa)) || !msp->ms_map.sm_loaded) + if ((txg != 0 && spa_writeable(spa)) || !msp->ms_map->sm_loaded) error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY); - if (error == 0 && !space_map_contains(&msp->ms_map, offset, size)) + if (error == 0 && !space_map_contains(msp->ms_map, offset, size)) error = ENOENT; if (error || txg == 0) { /* txg == 0 indicates dry run */ @@ -1568,12 +1771,12 @@ metaslab_claim_dva(spa_t *spa, const dva return (error); } - space_map_claim(&msp->ms_map, offset, size); + space_map_claim(msp->ms_map, offset, size); if (spa_writeable(spa)) { /* don't dirty if we're zdb(1M) */ - if (msp->ms_allocmap[txg & TXG_MASK].sm_space == 0) + if (msp->ms_allocmap[txg & TXG_MASK]->sm_space == 0) vdev_dirty(vd, VDD_METASLAB, msp, txg); - space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size); + space_map_add(msp->ms_allocmap[txg & TXG_MASK], offset, size); } mutex_exit(&msp->ms_lock); Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/space_map.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/space_map.c Wed Feb 27 11:42:28 2013 (r247397) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/space_map.c Wed Feb 27 14:45:23 2013 (r247398) @@ -114,6 +114,7 @@ space_map_add(space_map_t *sm, uint64_t int merge_before, merge_after; ASSERT(MUTEX_HELD(sm->sm_lock)); + VERIFY(!sm->sm_condensing); VERIFY(size != 0); VERIFY3U(start, >=, sm->sm_start); VERIFY3U(end, <=, sm->sm_start + sm->sm_size); @@ -198,6 +199,7 @@ space_map_remove(space_map_t *sm, uint64 int left_over, right_over; ASSERT(MUTEX_HELD(sm->sm_lock)); + VERIFY(!sm->sm_condensing); VERIFY(size != 0); VERIFY(P2PHASE(start, 1ULL << sm->sm_shift) == 0); VERIFY(P2PHASE(size, 1ULL << sm->sm_shift) == 0); @@ -267,6 +269,20 @@ space_map_contains(space_map_t *sm, uint } void +space_map_swap(space_map_t **msrc, space_map_t **mdst) +{ + space_map_t *sm; + + ASSERT(MUTEX_HELD((*msrc)->sm_lock)); + ASSERT0((*mdst)->sm_space); + ASSERT0(avl_numnodes(&(*mdst)->sm_root)); + + sm = *msrc; + *msrc = *mdst; + *mdst = sm; +} + +void space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest) { space_seg_t *ss; @@ -447,9 +463,9 @@ space_map_sync(space_map_t *sm, uint8_t space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx) { spa_t *spa = dmu_objset_spa(os); - void *cookie = NULL; + avl_tree_t *t = &sm->sm_root; space_seg_t *ss; - uint64_t bufsize, start, size, run_len, delta, sm_space; + uint64_t bufsize, start, size, run_len, total, sm_space, nodes; uint64_t *entry, *entry_map, *entry_map_end; ASSERT(MUTEX_HELD(sm->sm_lock)); @@ -478,13 +494,14 @@ space_map_sync(space_map_t *sm, uint8_t SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) | SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx)); - delta = 0; + total = 0; + nodes = avl_numnodes(&sm->sm_root); sm_space = sm->sm_space; - while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) { + for (ss = avl_first(t); ss != NULL; ss = AVL_NEXT(t, ss)) { size = ss->ss_end - ss->ss_start; start = (ss->ss_start - sm->sm_start) >> sm->sm_shift; - delta += size; + total += size; size >>= sm->sm_shift; while (size) { @@ -506,7 +523,6 @@ space_map_sync(space_map_t *sm, uint8_t start += run_len; size -= run_len; } - kmem_cache_free(space_seg_cache, ss); } if (entry != entry_map) { @@ -522,12 +538,11 @@ space_map_sync(space_map_t *sm, uint8_t * Ensure that the space_map's accounting wasn't changed * while we were in the middle of writing it out. */ + VERIFY3U(nodes, ==, avl_numnodes(&sm->sm_root)); VERIFY3U(sm->sm_space, ==, sm_space); + VERIFY3U(sm->sm_space, ==, total); zio_buf_free(entry_map, bufsize); - - sm->sm_space -= delta; - VERIFY0(sm->sm_space); } void Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h Wed Feb 27 11:42:28 2013 (r247397) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/metaslab_impl.h Wed Feb 27 14:45:23 2013 (r247398) @@ -66,20 +66,38 @@ struct metaslab_group { }; /* - * Each metaslab's free space is tracked in space map object in the MOS, - * which is only updated in syncing context. Each time we sync a txg, + * Each metaslab maintains an in-core free map (ms_map) that contains the + * current list of free segments. As blocks are allocated, the allocated + * segment is removed from the ms_map and added to a per txg allocation map. + * As blocks are freed, they are added to the per txg free map. These per + * txg maps allow us to process all allocations and frees in syncing context + * where it is safe to update the on-disk space maps. + * + * Each metaslab's free space is tracked in a space map object in the MOS, + * which is only updated in syncing context. Each time we sync a txg, * we append the allocs and frees from that txg to the space map object. * When the txg is done syncing, metaslab_sync_done() updates ms_smo - * to ms_smo_syncing. Everything in ms_smo is always safe to allocate. + * to ms_smo_syncing. Everything in ms_smo is always safe to allocate. + * + * To load the in-core free map we read the space map object from disk. + * This object contains a series of alloc and free records that are + * combined to make up the list of all free segments in this metaslab. These + * segments are represented in-core by the ms_map and are stored in an + * AVL tree. + * + * As the space map objects grows (as a result of the appends) it will + * eventually become space-inefficient. When the space map object is + * zfs_condense_pct/100 times the size of the minimal on-disk representation, + * we rewrite it in its minimized form. */ struct metaslab { kmutex_t ms_lock; /* metaslab lock */ space_map_obj_t ms_smo; /* synced space map object */ space_map_obj_t ms_smo_syncing; /* syncing space map object */ - space_map_t ms_allocmap[TXG_SIZE]; /* allocated this txg */ - space_map_t ms_freemap[TXG_SIZE]; /* freed this txg */ - space_map_t ms_defermap[TXG_DEFER_SIZE]; /* deferred frees */ - space_map_t ms_map; /* in-core free space map */ + space_map_t *ms_allocmap[TXG_SIZE]; /* allocated this txg */ + space_map_t *ms_freemap[TXG_SIZE]; /* freed this txg */ + space_map_t *ms_defermap[TXG_DEFER_SIZE]; /* deferred frees */ + space_map_t *ms_map; /* in-core free space map */ int64_t ms_deferspace; /* sum of ms_defermap[] space */ uint64_t ms_weight; /* weight vs. others in group */ metaslab_group_t *ms_group; /* metaslab group */ Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/space_map.h ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/space_map.h Wed Feb 27 11:42:28 2013 (r247397) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/space_map.h Wed Feb 27 14:45:23 2013 (r247398) @@ -40,17 +40,17 @@ extern "C" { typedef struct space_map_ops space_map_ops_t; typedef struct space_map { - avl_tree_t sm_root; /* AVL tree of map segments */ + avl_tree_t sm_root; /* offset-ordered segment AVL tree */ uint64_t sm_space; /* sum of all segments in the map */ uint64_t sm_start; /* start of map */ uint64_t sm_size; /* size of map */ uint8_t sm_shift; /* unit shift */ - uint8_t sm_pad[3]; /* unused */ uint8_t sm_loaded; /* map loaded? */ uint8_t sm_loading; /* map loading? */ + uint8_t sm_condensing; /* map condensing? */ kcondvar_t sm_load_cv; /* map load completion */ space_map_ops_t *sm_ops; /* space map block picker ops vector */ - avl_tree_t *sm_pp_root; /* picker-private AVL tree */ + avl_tree_t *sm_pp_root; /* size-ordered, picker-private tree */ void *sm_ppd; /* picker-private data */ kmutex_t *sm_lock; /* pointer to lock that protects map */ } space_map_t; @@ -149,6 +149,7 @@ extern void space_map_add(space_map_t *s extern void space_map_remove(space_map_t *sm, uint64_t start, uint64_t size); extern boolean_t space_map_contains(space_map_t *sm, uint64_t start, uint64_t size); +extern void space_map_swap(space_map_t **msrc, space_map_t **mdest); extern void space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest); extern void space_map_walk(space_map_t *sm, Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Wed Feb 27 11:42:28 2013 (r247397) +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev.c Wed Feb 27 14:45:23 2013 (r247398) @@ -1847,6 +1847,7 @@ vdev_dtl_sync(vdev_t *vd, uint64_t txg) space_map_truncate(smo, mos, tx); space_map_sync(&smsync, SM_ALLOC, smo, mos, tx); + space_map_vacate(&smsync, NULL, NULL); space_map_destroy(&smsync);
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