/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/zfs_context.h>
#include <sys/spa_impl.h>
#include <sys/dmu.h>
#include <sys/dmu_tx.h>
#include <sys/space_map.h>
#include <sys/metaslab_impl.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
uint64_t metaslab_aliquot = 512ULL << 10;
uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */
/*
* Minimum size which forces the dynamic allocator to change
* it's allocation strategy. Once the space map cannot satisfy
* an allocation of this size then it switches to using more
* aggressive strategy (i.e search by size rather than offset).
*/
uint64_t metaslab_df_alloc_threshold = SPA_MAXBLOCKSIZE;
/*
* 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
* switch to using best-fit allocations.
*/
int metaslab_df_free_pct = 30;
/*
* ==========================================================================
* Metaslab classes
* ==========================================================================
*/
metaslab_class_t *
metaslab_class_create(space_map_ops_t *ops)
{
metaslab_class_t *mc;
mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
mc->mc_rotor = NULL;
mc->mc_ops = ops;
return (mc);
}
void
metaslab_class_destroy(metaslab_class_t *mc)
{
metaslab_group_t *mg;
while ((mg = mc->mc_rotor) != NULL) {
metaslab_class_remove(mc, mg);
metaslab_group_destroy(mg);
}
kmem_free(mc, sizeof (metaslab_class_t));
}
void
metaslab_class_add(metaslab_class_t *mc, metaslab_group_t *mg)
{
metaslab_group_t *mgprev, *mgnext;
ASSERT(mg->mg_class == NULL);
if ((mgprev = mc->mc_rotor) == NULL) {
mg->mg_prev = mg;
mg->mg_next = mg;
} else {
mgnext = mgprev->mg_next;
mg->mg_prev = mgprev;
mg->mg_next = mgnext;
mgprev->mg_next = mg;
mgnext->mg_prev = mg;
}
mc->mc_rotor = mg;
mg->mg_class = mc;
}
void
metaslab_class_remove(metaslab_class_t *mc, metaslab_group_t *mg)
{
metaslab_group_t *mgprev, *mgnext;
ASSERT(mg->mg_class == mc);
mgprev = mg->mg_prev;
mgnext = mg->mg_next;
if (mg == mgnext) {
mc->mc_rotor = NULL;
} else {
mc->mc_rotor = mgnext;
mgprev->mg_next = mgnext;
mgnext->mg_prev = mgprev;
}
mg->mg_prev = NULL;
mg->mg_next = NULL;
mg->mg_class = NULL;
}
/*
* ==========================================================================
* Metaslab groups
* ==========================================================================
*/
static int
metaslab_compare(const void *x1, const void *x2)
{
const metaslab_t *m1 = x1;
const metaslab_t *m2 = x2;
if (m1->ms_weight < m2->ms_weight)
return (1);
if (m1->ms_weight > m2->ms_weight)
return (-1);
/*
* If the weights are identical, use the offset to force uniqueness.
*/
if (m1->ms_map.sm_start < m2->ms_map.sm_start)
return (-1);
if (m1->ms_map.sm_start > m2->ms_map.sm_start)
return (1);
ASSERT3P(m1, ==, m2);
return (0);
}
metaslab_group_t *
metaslab_group_create(metaslab_class_t *mc, vdev_t *vd)
{
metaslab_group_t *mg;
mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP);
mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL);
avl_create(&mg->mg_metaslab_tree, metaslab_compare,
sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node));
mg->mg_aliquot = metaslab_aliquot * MAX(1, vd->vdev_children);
mg->mg_vd = vd;
metaslab_class_add(mc, mg);
return (mg);
}
void
metaslab_group_destroy(metaslab_group_t *mg)
{
avl_destroy(&mg->mg_metaslab_tree);
mutex_destroy(&mg->mg_lock);
kmem_free(mg, sizeof (metaslab_group_t));
}
static void
metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp)
{
mutex_enter(&mg->mg_lock);
ASSERT(msp->ms_group == NULL);
msp->ms_group = mg;
msp->ms_weight = 0;
avl_add(&mg->mg_metaslab_tree, msp);
mutex_exit(&mg->mg_lock);
}
static void
metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp)
{
mutex_enter(&mg->mg_lock);
ASSERT(msp->ms_group == mg);
avl_remove(&mg->mg_metaslab_tree, msp);
msp->ms_group = NULL;
mutex_exit(&mg->mg_lock);
}
static void
metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
{
/*
* Although in principle the weight can be any value, in
* practice we do not use values in the range [1, 510].
*/
ASSERT(weight >= SPA_MINBLOCKSIZE-1 || weight == 0);
ASSERT(MUTEX_HELD(&msp->ms_lock));
mutex_enter(&mg->mg_lock);
ASSERT(msp->ms_group == mg);
avl_remove(&mg->mg_metaslab_tree, msp);
msp->ms_weight = weight;
avl_add(&mg->mg_metaslab_tree, msp);
mutex_exit(&mg->mg_lock);
}
/*
* This is a helper function that can be used by the allocator to find
* a suitable block to allocate. This will search the specified AVL
* tree looking for a block that matches the specified criteria.
*/
static uint64_t
metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
uint64_t align)
{
space_seg_t *ss, ssearch;
avl_index_t where;
ssearch.ss_start = *cursor;
ssearch.ss_end = *cursor + size;
ss = avl_find(t, &ssearch, &where);
if (ss == NULL)
ss = avl_nearest(t, where, AVL_AFTER);
while (ss != NULL) {
uint64_t offset = P2ROUNDUP(ss->ss_start, align);
if (offset + size <= ss->ss_end) {
*cursor = offset + size;
return (offset);
}
ss = AVL_NEXT(t, ss);
}
/*
* If we know we've searched the whole map (*cursor == 0), give up.
* Otherwise, reset the cursor to the beginning and try again.
*/
if (*cursor == 0)
return (-1ULL);
*cursor = 0;
return (metaslab_block_picker(t, cursor, size, align));
}
/*
* ==========================================================================
* The first-fit block allocator
* ==========================================================================
*/
static void
metaslab_ff_load(space_map_t *sm)
{
ASSERT(sm->sm_ppd == NULL);
sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
sm->sm_pp_root = NULL;
}
static void
metaslab_ff_unload(space_map_t *sm)
{
kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
sm->sm_ppd = NULL;
}
static uint64_t
metaslab_ff_alloc(space_map_t *sm, uint64_t size)
{
avl_tree_t *t = &sm->sm_root;
uint64_t align = size & -size;
uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
return (metaslab_block_picker(t, cursor, size, align));
}
/* ARGSUSED */
static void
metaslab_ff_claim(space_map_t *sm, uint64_t start, uint64_t size)
{
/* No need to update cursor */
}
/* ARGSUSED */
static void
metaslab_ff_free(space_map_t *sm, uint64_t start, uint64_t size)
{
/* No need to update cursor */
}
static space_map_ops_t metaslab_ff_ops = {
metaslab_ff_load,
metaslab_ff_unload,
metaslab_ff_alloc,
metaslab_ff_claim,
metaslab_ff_free,
NULL /* maxsize */
};
/*
* Dynamic block allocator -
* Uses the first fit allocation scheme until space get low and then
* adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
* and metaslab_df_free_pct to determine when to switch the allocation scheme.
*/
uint64_t
metaslab_df_maxsize(space_map_t *sm)
{
avl_tree_t *t = sm->sm_pp_root;
space_seg_t *ss;
if (t == NULL || (ss = avl_last(t)) == NULL)
return (0ULL);
return (ss->ss_end - ss->ss_start);
}
static int
metaslab_df_seg_compare(const void *x1, const void *x2)
{
const space_seg_t *s1 = x1;
const space_seg_t *s2 = x2;
uint64_t ss_size1 = s1->ss_end - s1->ss_start;
uint64_t ss_size2 = s2->ss_end - s2->ss_start;
if (ss_size1 < ss_size2)
return (-1);
if (ss_size1 > ss_size2)
return (1);
if (s1->ss_start < s2->ss_start)
return (-1);
if (s1->ss_start > s2->ss_start)
return (1);
return (0);
}
static void
metaslab_df_load(space_map_t *sm)
{
space_seg_t *ss;
ASSERT(sm->sm_ppd == NULL);
sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
sm->sm_pp_root = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
avl_create(sm->sm_pp_root, metaslab_df_seg_compare,
sizeof (space_seg_t), offsetof(struct space_seg, ss_pp_node));
for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
avl_add(sm->sm_pp_root, ss);
}
static void
metaslab_df_unload(space_map_t *sm)
{
void *cookie = NULL;
kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
sm->sm_ppd = NULL;
while (avl_destroy_nodes(sm->sm_pp_root, &cookie) != NULL) {
/* tear down the tree */
}
avl_destroy(sm->sm_pp_root);
kmem_free(sm->sm_pp_root, sizeof (avl_tree_t));
sm->sm_pp_root = NULL;
}
static uint64_t
metaslab_df_alloc(space_map_t *sm, uint64_t size)
{
avl_tree_t *t = &sm->sm_root;
uint64_t align = size & -size;
uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
uint64_t max_size = metaslab_df_maxsize(sm);
int free_pct = sm->sm_space * 100 / sm->sm_size;
ASSERT(MUTEX_HELD(sm->sm_lock));
ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
if (max_size < size)
return (-1ULL);
/*
* If we're running low on space switch to using the size
* sorted AVL tree (best-fit).
*/
if (max_size < metaslab_df_alloc_threshold ||
free_pct < metaslab_df_free_pct) {
t = sm->sm_pp_root;
*cursor = 0;
}
return (metaslab_block_picker(t, cursor, size, 1ULL));
}
/* ARGSUSED */
static void
metaslab_df_claim(space_map_t *sm, uint64_t start, uint64_t size)
{
/* No need to update cursor */
}
/* ARGSUSED */
static void
metaslab_df_free(space_map_t *sm, uint64_t start, uint64_t size)
{
/* No need to update cursor */
}
static space_map_ops_t metaslab_df_ops = {
metaslab_df_load,
metaslab_df_unload,
metaslab_df_alloc,
metaslab_df_claim,
metaslab_df_free,
metaslab_df_maxsize
};
space_map_ops_t *zfs_metaslab_ops = &metaslab_df_ops;
/*
* ==========================================================================
* Metaslabs
* ==========================================================================
*/
metaslab_t *
metaslab_init(metaslab_group_t *mg, space_map_obj_t *smo,
uint64_t start, uint64_t size, uint64_t txg)
{
vdev_t *vd = mg->mg_vd;
metaslab_t *msp;
msp = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP);
mutex_init(&msp->ms_lock, NULL, MUTEX_DEFAULT, NULL);
msp->ms_smo_syncing = *smo;
/*
* We create the main space map here, but we don't create the
* allocmaps and freemaps until metaslab_sync_done(). This serves
* two purposes: it allows metaslab_sync_done() to detect the
* 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,
vd->vdev_ashift, &msp->ms_lock);
metaslab_group_add(mg, msp);
/*
* 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.
*/
if (txg <= TXG_INITIAL)
metaslab_sync_done(msp, 0);
if (txg != 0) {
/*
* The vdev is dirty, but the metaslab isn't -- it just needs
* to have metaslab_sync_done() invoked from vdev_sync_done().
* [We could just dirty the metaslab, but that would cause us
* to allocate a space map object for it, which is wasteful
* and would mess up the locality logic in metaslab_weight().]
*/
ASSERT(TXG_CLEAN(txg) == spa_last_synced_txg(vd->vdev_spa));
vdev_dirty(vd, 0, NULL, txg);
vdev_dirty(vd, VDD_METASLAB, msp, TXG_CLEAN(txg));
}
return (msp);
}
void
metaslab_fini(metaslab_t *msp)
{
metaslab_group_t *mg = msp->ms_group;
int t;
vdev_space_update(mg->mg_vd, -msp->ms_map.sm_size,
-msp->ms_smo.smo_alloc, B_TRUE);
metaslab_group_remove(mg, msp);
mutex_enter(&msp->ms_lock);
space_map_unload(&msp->ms_map);
space_map_destroy(&msp->ms_map);
for (t = 0; t < TXG_SIZE; t++) {
space_map_destroy(&msp->ms_allocmap[t]);
space_map_destroy(&msp->ms_freemap[t]);
}
mutex_exit(&msp->ms_lock);
mutex_destroy(&msp->ms_lock);
kmem_free(msp, sizeof (metaslab_t));
}
#define METASLAB_WEIGHT_PRIMARY (1ULL << 63)
#define METASLAB_WEIGHT_SECONDARY (1ULL << 62)
#define METASLAB_ACTIVE_MASK \
(METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY)
#define METASLAB_SMO_BONUS_MULTIPLIER 2
static uint64_t
metaslab_weight(metaslab_t *msp)
{
metaslab_group_t *mg = msp->ms_group;
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;
ASSERT(MUTEX_HELD(&msp->ms_lock));
/*
* The baseline weight is the metaslab's free space.
*/
space = sm->sm_size - smo->smo_alloc;
weight = space;
/*
* Modern disks have uniform bit density and constant angular velocity.
* Therefore, the outer recording zones are faster (higher bandwidth)
* than the inner zones by the ratio of outer to inner track diameter,
* which is typically around 2:1. We account for this by assigning
* higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
* In effect, this means that we'll select the metaslab with the most
* free bandwidth rather than simply the one with the most free space.
*/
weight = 2 * weight -
((sm->sm_start >> vd->vdev_ms_shift) * weight) / vd->vdev_ms_count;
ASSERT(weight >= space && weight <= 2 * space);
/*
* For locality, assign higher weight to metaslabs we've used before.
*/
if (smo->smo_object != 0)
weight *= METASLAB_SMO_BONUS_MULTIPLIER;
ASSERT(weight >= space &&
weight <= 2 * METASLAB_SMO_BONUS_MULTIPLIER * space);
/*
* If this metaslab is one we're actively using, adjust its weight to
* make it preferable to any inactive metaslab so we'll polish it off.
*/
weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK);
return (weight);
}
static int
metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
{
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));
if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
int error = space_map_load(sm, sm_ops, SM_FREE, &msp->ms_smo,
msp->ms_group->mg_vd->vdev_spa->spa_meta_objset);
if (error) {
metaslab_group_sort(msp->ms_group, msp, 0);
return (error);
}
/*
* If we were able to load the map then make sure
* that this map is still able to satisfy our request.
*/
if (msp->ms_weight < size)
return (ENOSPC);
metaslab_group_sort(msp->ms_group, msp,
msp->ms_weight | activation_weight);
}
ASSERT(sm->sm_loaded);
ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK);
return (0);
}
static void
metaslab_passivate(metaslab_t *msp, uint64_t size)
{
/*
* 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 || 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);
}
/*
* Write a metaslab to disk in the context of the specified transaction group.
*/
void
metaslab_sync(metaslab_t *msp, uint64_t txg)
{
vdev_t *vd = msp->ms_group->mg_vd;
spa_t *spa = vd->vdev_spa;
objset_t *mos = spa->spa_meta_objset;
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;
int t;
tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
/*
* The only state that can actually be changing concurrently with
* metaslab_sync() is the metaslab's ms_map. No other thread can
* be modifying this txg's allocmap, freemap, freed_map, or smo.
* Therefore, we only hold ms_lock to satify 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.
*/
mutex_enter(&msp->ms_lock);
if (smo->smo_object == 0) {
ASSERT(smo->smo_objsize == 0);
ASSERT(smo->smo_alloc == 0);
mutex_exit(&msp->ms_lock);
smo->smo_object = dmu_object_alloc(mos,
DMU_OT_SPACE_MAP, 1 << SPACE_MAP_BLOCKSHIFT,
DMU_OT_SPACE_MAP_HEADER, sizeof (*smo), tx);
ASSERT(smo->smo_object != 0);
dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) *
(sm->sm_start >> vd->vdev_ms_shift),
sizeof (uint64_t), &smo->smo_object, tx);
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 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 (t = 1; t < TXG_CONCURRENT_STATES; t++)
space_map_walk(&msp->ms_allocmap[(txg + t) & TXG_MASK],
space_map_remove, allocmap);
mutex_exit(&msp->ms_lock);
space_map_truncate(smo, mos, tx);
mutex_enter(&msp->ms_lock);
}
space_map_sync(allocmap, SM_ALLOC, smo, mos, tx);
space_map_sync(freemap, SM_FREE, smo, mos, tx);
mutex_exit(&msp->ms_lock);
VERIFY(0 == 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));
dmu_buf_rele(db, FTAG);
dmu_tx_commit(tx);
}
/*
* Called after a transaction group has completely synced to mark
* all of the metaslab's free space as usable.
*/
void
metaslab_sync_done(metaslab_t *msp, uint64_t txg)
{
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];
metaslab_group_t *mg = msp->ms_group;
vdev_t *vd = mg->mg_vd;
int t;
mutex_enter(&msp->ms_lock);
/*
* If this metaslab is just becoming available, initialize its
* allocmaps and freemaps and add its capacity to the vdev.
*/
if (freed_map->sm_size == 0) {
for (t = 0; t < TXG_SIZE; t++) {
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,
sm->sm_size, sm->sm_shift, sm->sm_lock);
}
vdev_space_update(vd, sm->sm_size, 0, B_TRUE);
}
vdev_space_update(vd, 0, smosync->smo_alloc - smo->smo_alloc, B_TRUE);
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 everything we freed in this txg to the map.
*/
space_map_load_wait(sm);
space_map_vacate(freed_map, sm->sm_loaded ? space_map_free : NULL, sm);
*smo = *smosync;
/*
* 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
* loaded a moment later, the map wouldn't reflect those allocations.)
*/
if (sm->sm_loaded && (msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
int evictable = 1;
for (t = 1; t < TXG_CONCURRENT_STATES; t++)
if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space)
evictable = 0;
if (evictable)
space_map_unload(sm);
}
metaslab_group_sort(mg, msp, metaslab_weight(msp));
mutex_exit(&msp->ms_lock);
}
static uint64_t
metaslab_distance(metaslab_t *msp, dva_t *dva)
{
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;
if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva))
return (1ULL << 63);
if (offset < start)
return ((start - offset) << ms_shift);
if (offset > start)
return ((offset - start) << ms_shift);
return (0);
}
static uint64_t
metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
uint64_t min_distance, dva_t *dva, int d)
{
metaslab_t *msp = NULL;
uint64_t offset = -1ULL;
avl_tree_t *t = &mg->mg_metaslab_tree;
uint64_t activation_weight;
uint64_t target_distance;
int i;
activation_weight = METASLAB_WEIGHT_PRIMARY;
for (i = 0; i < d; i++) {
if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
activation_weight = METASLAB_WEIGHT_SECONDARY;
break;
}
}
for (;;) {
boolean_t was_active;
mutex_enter(&mg->mg_lock);
for (msp = avl_first(t); msp; msp = AVL_NEXT(t, msp)) {
if (msp->ms_weight < size) {
mutex_exit(&mg->mg_lock);
return (-1ULL);
}
was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
if (activation_weight == METASLAB_WEIGHT_PRIMARY)
break;
target_distance = min_distance +
(msp->ms_smo.smo_alloc ? 0 : min_distance >> 1);
for (i = 0; i < d; i++)
if (metaslab_distance(msp, &dva[i]) <
target_distance)
break;
if (i == d)
break;
}
mutex_exit(&mg->mg_lock);
if (msp == NULL)
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
* another thread may have changed the weight while we
* were blocked on the metaslab lock.
*/
if (msp->ms_weight < size || (was_active &&
!(msp->ms_weight & METASLAB_ACTIVE_MASK) &&
activation_weight == METASLAB_WEIGHT_PRIMARY)) {
mutex_exit(&msp->ms_lock);
continue;
}
if ((msp->ms_weight & METASLAB_WEIGHT_SECONDARY) &&
activation_weight == METASLAB_WEIGHT_PRIMARY) {
metaslab_passivate(msp,
msp->ms_weight & ~METASLAB_ACTIVE_MASK);
mutex_exit(&msp->ms_lock);
continue;
}
if (metaslab_activate(msp, activation_weight, size) != 0) {
mutex_exit(&msp->ms_lock);
continue;
}
if ((offset = space_map_alloc(&msp->ms_map, size)) != -1ULL)
break;
metaslab_passivate(msp, size - 1);
mutex_exit(&msp->ms_lock);
}
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, size);
mutex_exit(&msp->ms_lock);
return (offset);
}
/*
* Allocate a block for the specified i/o.
*/
static int
metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize,
dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags)
{
metaslab_group_t *mg, *rotor;
vdev_t *vd;
int dshift = 3;
int all_zero;
int zio_lock = B_FALSE;
boolean_t allocatable;
uint64_t offset = -1ULL;
uint64_t asize;
uint64_t distance;
ASSERT(!DVA_IS_VALID(&dva[d]));
/*
* For testing, make some blocks above a certain size be gang blocks.
*/
if (psize >= metaslab_gang_bang && (LBOLT & 3) == 0)
return (ENOSPC);
/*
* Start at the rotor and loop through all mgs until we find something.
* Note that there's no locking on mc_rotor or mc_allocated because
* nothing actually breaks if we miss a few updates -- we just won't
* allocate quite as evenly. It all balances out over time.
*
* If we are doing ditto or log blocks, try to spread them across
* consecutive vdevs. If we're forced to reuse a vdev before we've
* allocated all of our ditto blocks, then try and spread them out on
* that vdev as much as possible. If it turns out to not be possible,
* gradually lower our standards until anything becomes acceptable.
* Also, allocating on consecutive vdevs (as opposed to random vdevs)
* gives us hope of containing our fault domains to something we're
* able to reason about. Otherwise, any two top-level vdev failures
* will guarantee the loss of data. With consecutive allocation,
* only two adjacent top-level vdev failures will result in data loss.
*
* If we are doing gang blocks (hintdva is non-NULL), try to keep
* ourselves on the same vdev as our gang block header. That
* way, we can hope for locality in vdev_cache, plus it makes our
* fault domains something tractable.
*/
if (hintdva) {
vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d]));
if (flags & METASLAB_HINTBP_AVOID)
mg = vd->vdev_mg->mg_next;
else
mg = vd->vdev_mg;
} else if (d != 0) {
vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1]));
mg = vd->vdev_mg->mg_next;
} else {
mg = mc->mc_rotor;
}
/*
* If the hint put us into the wrong class, just follow the rotor.
*/
if (mg->mg_class != mc)
mg = mc->mc_rotor;
rotor = mg;
top:
all_zero = B_TRUE;
do {
vd = mg->mg_vd;
/*
* Don't allocate from faulted devices.
*/
if (zio_lock) {
spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
allocatable = vdev_allocatable(vd);
spa_config_exit(spa, SCL_ZIO, FTAG);
} else {
allocatable = vdev_allocatable(vd);
}
if (!allocatable)
goto next;
/*
* Avoid writing single-copy data to a failing vdev
*/
if ((vd->vdev_stat.vs_write_errors > 0 ||
vd->vdev_state < VDEV_STATE_HEALTHY) &&
d == 0 && dshift == 3) {
all_zero = B_FALSE;
goto next;
}
ASSERT(mg->mg_class == mc);
distance = vd->vdev_asize >> dshift;
if (distance <= (1ULL << vd->vdev_ms_shift))
distance = 0;
else
all_zero = B_FALSE;
asize = vdev_psize_to_asize(vd, psize);
ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0);
offset = metaslab_group_alloc(mg, asize, txg, distance, dva, d);
if (offset != -1ULL) {
/*
* If we've just selected this metaslab group,
* figure out whether the corresponding vdev is
* over- or under-used relative to the pool,
* and set an allocation bias to even it out.
*/
if (mc->mc_allocated == 0) {
vdev_stat_t *vs = &vd->vdev_stat;
uint64_t alloc, space;
int64_t vu, su;
alloc = spa_get_alloc(spa);
space = spa_get_space(spa);
/*
* Determine percent used in units of 0..1024.
* (This is just to avoid floating point.)
*/
vu = (vs->vs_alloc << 10) / (vs->vs_space + 1);
su = (alloc << 10) / (space + 1);
/*
* Bias by at most +/- 25% of the aliquot.
*/
mg->mg_bias = ((su - vu) *
(int64_t)mg->mg_aliquot) / (1024 * 4);
}
if (atomic_add_64_nv(&mc->mc_allocated, asize) >=
mg->mg_aliquot + mg->mg_bias) {
mc->mc_rotor = mg->mg_next;
mc->mc_allocated = 0;
}
DVA_SET_VDEV(&dva[d], vd->vdev_id);
DVA_SET_OFFSET(&dva[d], offset);
DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER));
DVA_SET_ASIZE(&dva[d], asize);
return (0);
}
next:
mc->mc_rotor = mg->mg_next;
mc->mc_allocated = 0;
} while ((mg = mg->mg_next) != rotor);
if (!all_zero) {
dshift++;
ASSERT(dshift < 64);
goto top;
}
if (!allocatable && !zio_lock) {
dshift = 3;
zio_lock = B_TRUE;
goto top;
}
bzero(&dva[d], sizeof (dva_t));
return (ENOSPC);
}
/*
* Free the block represented by DVA in the context of the specified
* transaction group.
*/
static void
metaslab_free_dva(spa_t *spa, const dva_t *dva, uint64_t txg, boolean_t now)
{
uint64_t vdev = DVA_GET_VDEV(dva);
uint64_t offset = DVA_GET_OFFSET(dva);
uint64_t size = DVA_GET_ASIZE(dva);
vdev_t *vd;
metaslab_t *msp;
ASSERT(DVA_IS_VALID(dva));
if (txg > spa_freeze_txg(spa))
return;
if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
(offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) {
cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu",
(u_longlong_t)vdev, (u_longlong_t)offset);
ASSERT(0);
return;
}
msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
if (DVA_GET_GANG(dva))
size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
mutex_enter(&msp->ms_lock);
if (now) {
space_map_remove(&msp->ms_allocmap[txg & TXG_MASK],
offset, size);
space_map_free(&msp->ms_map, offset, size);
} else {
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);
}
mutex_exit(&msp->ms_lock);
}
/*
* Intent log support: upon opening the pool after a crash, notify the SPA
* of blocks that the intent log has allocated for immediate write, but
* which are still considered free by the SPA because the last transaction
* group didn't commit yet.
*/
static int
metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
{
uint64_t vdev = DVA_GET_VDEV(dva);
uint64_t offset = DVA_GET_OFFSET(dva);
uint64_t size = DVA_GET_ASIZE(dva);
vdev_t *vd;
metaslab_t *msp;
int error;
ASSERT(DVA_IS_VALID(dva));
if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
(offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count)
return (ENXIO);
msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
if (DVA_GET_GANG(dva))
size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
mutex_enter(&msp->ms_lock);
error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY, 0);
if (error || txg == 0) { /* txg == 0 indicates dry run */
mutex_exit(&msp->ms_lock);
return (error);
}
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)
vdev_dirty(vd, VDD_METASLAB, msp, txg);
space_map_add(&msp->ms_allocmap[txg & TXG_MASK], offset, size);
}
mutex_exit(&msp->ms_lock);
return (0);
}
int
metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
int ndvas, uint64_t txg, blkptr_t *hintbp, int flags)
{
dva_t *dva = bp->blk_dva;
dva_t *hintdva = hintbp->blk_dva;
int error = 0;
ASSERT(bp->blk_birth == 0);
spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
if (mc->mc_rotor == NULL) { /* no vdevs in this class */
spa_config_exit(spa, SCL_ALLOC, FTAG);
return (ENOSPC);
}
ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa));
ASSERT(BP_GET_NDVAS(bp) == 0);
ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp));
for (int d = 0; d < ndvas; d++) {
error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva,
txg, flags);
if (error) {
for (d--; d >= 0; d--) {
metaslab_free_dva(spa, &dva[d], txg, B_TRUE);
bzero(&dva[d], sizeof (dva_t));
}
spa_config_exit(spa, SCL_ALLOC, FTAG);
return (error);
}
}
ASSERT(error == 0);
ASSERT(BP_GET_NDVAS(bp) == ndvas);
spa_config_exit(spa, SCL_ALLOC, FTAG);
bp->blk_birth = txg;
return (0);
}
void
metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now)
{
const dva_t *dva = bp->blk_dva;
int ndvas = BP_GET_NDVAS(bp);
ASSERT(!BP_IS_HOLE(bp));
ASSERT(!now || bp->blk_birth >= spa->spa_syncing_txg);
spa_config_enter(spa, SCL_FREE, FTAG, RW_READER);
for (int d = 0; d < ndvas; d++)
metaslab_free_dva(spa, &dva[d], txg, now);
spa_config_exit(spa, SCL_FREE, FTAG);
}
int
metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
{
const dva_t *dva = bp->blk_dva;
int ndvas = BP_GET_NDVAS(bp);
int error = 0;
ASSERT(!BP_IS_HOLE(bp));
if (txg != 0) {
/*
* First do a dry run to make sure all DVAs are claimable,
* so we don't have to unwind from partial failures below.
*/
if ((error = metaslab_claim(spa, bp, 0)) != 0)
return (error);
}
spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
for (int d = 0; d < ndvas; d++)
if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0)
break;
spa_config_exit(spa, SCL_ALLOC, FTAG);
ASSERT(error == 0 || txg == 0);
return (error);
}
