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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#include "bcache.h"#include "btree.h"#include "debug.h"#include "writeback.h"
#include <linux/delay.h>#include <linux/kthread.h>#include <linux/sched/clock.h>#include <trace/events/bcache.h>
static void update_gc_after_writeback(struct cache_set *c){ if (c->gc_after_writeback != (BCH_ENABLE_AUTO_GC) || c->gc_stats.in_use < BCH_AUTO_GC_DIRTY_THRESHOLD) return;
c->gc_after_writeback |= BCH_DO_AUTO_GC;}
/* Rate limiting */static uint64_t __calc_target_rate(struct cached_dev *dc){ struct cache_set *c = dc->disk.c;
/* * This is the size of the cache, minus the amount used for * flash-only devices */ uint64_t cache_sectors = c->nbuckets * c->cache->sb.bucket_size - atomic_long_read(&c->flash_dev_dirty_sectors);
/* * Unfortunately there is no control of global dirty data. If the * user states that they want 10% dirty data in the cache, and has, * e.g., 5 backing volumes of equal size, we try and ensure each * backing volume uses about 2% of the cache for dirty data. */ uint32_t bdev_share = div64_u64(bdev_nr_sectors(dc->bdev) << WRITEBACK_SHARE_SHIFT, c->cached_dev_sectors);
uint64_t cache_dirty_target = div_u64(cache_sectors * dc->writeback_percent, 100);
/* Ensure each backing dev gets at least one dirty share */ if (bdev_share < 1) bdev_share = 1;
return (cache_dirty_target * bdev_share) >> WRITEBACK_SHARE_SHIFT;}
static void __update_writeback_rate(struct cached_dev *dc){ /* * PI controller: * Figures out the amount that should be written per second. * * First, the error (number of sectors that are dirty beyond our * target) is calculated. The error is accumulated (numerically * integrated). * * Then, the proportional value and integral value are scaled * based on configured values. These are stored as inverses to * avoid fixed point math and to make configuration easy-- e.g. * the default value of 40 for writeback_rate_p_term_inverse * attempts to write at a rate that would retire all the dirty * blocks in 40 seconds. * * The writeback_rate_i_inverse value of 10000 means that 1/10000th * of the error is accumulated in the integral term per second. * This acts as a slow, long-term average that is not subject to * variations in usage like the p term. */ int64_t target = __calc_target_rate(dc); int64_t dirty = bcache_dev_sectors_dirty(&dc->disk); int64_t error = dirty - target; int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); int64_t integral_scaled; uint32_t new_rate;
/* * We need to consider the number of dirty buckets as well * when calculating the proportional_scaled, Otherwise we might * have an unreasonable small writeback rate at a highly fragmented situation * when very few dirty sectors consumed a lot dirty buckets, the * worst case is when dirty buckets reached cutoff_writeback_sync and * dirty data is still not even reached to writeback percent, so the rate * still will be at the minimum value, which will cause the write * stuck at a non-writeback mode. */ struct cache_set *c = dc->disk.c;
int64_t dirty_buckets = c->nbuckets - c->avail_nbuckets;
if (dc->writeback_consider_fragment && c->gc_stats.in_use > BCH_WRITEBACK_FRAGMENT_THRESHOLD_LOW && dirty > 0) { int64_t fragment = div_s64((dirty_buckets * c->cache->sb.bucket_size), dirty); int64_t fp_term; int64_t fps;
if (c->gc_stats.in_use <= BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID) { fp_term = (int64_t)dc->writeback_rate_fp_term_low * (c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_LOW); } else if (c->gc_stats.in_use <= BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH) { fp_term = (int64_t)dc->writeback_rate_fp_term_mid * (c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID); } else { fp_term = (int64_t)dc->writeback_rate_fp_term_high * (c->gc_stats.in_use - BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH); } fps = div_s64(dirty, dirty_buckets) * fp_term; if (fragment > 3 && fps > proportional_scaled) { /* Only overrite the p when fragment > 3 */ proportional_scaled = fps; } }
if ((error < 0 && dc->writeback_rate_integral > 0) || (error > 0 && time_before64(local_clock(), dc->writeback_rate.next + NSEC_PER_MSEC))) { /* * Only decrease the integral term if it's more than * zero. Only increase the integral term if the device * is keeping up. (Don't wind up the integral * ineffectively in either case). * * It's necessary to scale this by * writeback_rate_update_seconds to keep the integral * term dimensioned properly. */ dc->writeback_rate_integral += error * dc->writeback_rate_update_seconds; }
integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse);
new_rate = clamp_t(int32_t, (proportional_scaled + integral_scaled), dc->writeback_rate_minimum, NSEC_PER_SEC);
dc->writeback_rate_proportional = proportional_scaled; dc->writeback_rate_integral_scaled = integral_scaled; dc->writeback_rate_change = new_rate - atomic_long_read(&dc->writeback_rate.rate); atomic_long_set(&dc->writeback_rate.rate, new_rate); dc->writeback_rate_target = target;}
static bool idle_counter_exceeded(struct cache_set *c){ int counter, dev_nr;
/* * If c->idle_counter is overflow (idel for really long time), * reset as 0 and not set maximum rate this time for code * simplicity. */ counter = atomic_inc_return(&c->idle_counter); if (counter <= 0) { atomic_set(&c->idle_counter, 0); return false; }
dev_nr = atomic_read(&c->attached_dev_nr); if (dev_nr == 0) return false;
/* * c->idle_counter is increased by writeback thread of all * attached backing devices, in order to represent a rough * time period, counter should be divided by dev_nr. * Otherwise the idle time cannot be larger with more backing * device attached. * The following calculation equals to checking * (counter / dev_nr) < (dev_nr * 6) */ if (counter < (dev_nr * dev_nr * 6)) return false;
return true;}
/* * Idle_counter is increased every time when update_writeback_rate() is * called. If all backing devices attached to the same cache set have * identical dc->writeback_rate_update_seconds values, it is about 6 * rounds of update_writeback_rate() on each backing device before * c->at_max_writeback_rate is set to 1, and then max wrteback rate set * to each dc->writeback_rate.rate. * In order to avoid extra locking cost for counting exact dirty cached * devices number, c->attached_dev_nr is used to calculate the idle * throushold. It might be bigger if not all cached device are in write- * back mode, but it still works well with limited extra rounds of * update_writeback_rate(). */static bool set_at_max_writeback_rate(struct cache_set *c, struct cached_dev *dc){ /* Don't sst max writeback rate if it is disabled */ if (!c->idle_max_writeback_rate_enabled) return false;
/* Don't set max writeback rate if gc is running */ if (!c->gc_mark_valid) return false;
if (!idle_counter_exceeded(c)) return false;
if (atomic_read(&c->at_max_writeback_rate) != 1) atomic_set(&c->at_max_writeback_rate, 1);
atomic_long_set(&dc->writeback_rate.rate, INT_MAX);
/* keep writeback_rate_target as existing value */ dc->writeback_rate_proportional = 0; dc->writeback_rate_integral_scaled = 0; dc->writeback_rate_change = 0;
/* * In case new I/O arrives during before * set_at_max_writeback_rate() returns. */ if (!idle_counter_exceeded(c) || !atomic_read(&c->at_max_writeback_rate)) return false;
return true;}
static void update_writeback_rate(struct work_struct *work){ struct cached_dev *dc = container_of(to_delayed_work(work), struct cached_dev, writeback_rate_update); struct cache_set *c = dc->disk.c;
/* * should check BCACHE_DEV_RATE_DW_RUNNING before calling * cancel_delayed_work_sync(). */ set_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags); /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */ smp_mb__after_atomic();
/* * CACHE_SET_IO_DISABLE might be set via sysfs interface, * check it here too. */ if (!test_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags) || test_bit(CACHE_SET_IO_DISABLE, &c->flags)) { clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags); /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */ smp_mb__after_atomic(); return; }
/* * If the whole cache set is idle, set_at_max_writeback_rate() * will set writeback rate to a max number. Then it is * unncessary to update writeback rate for an idle cache set * in maximum writeback rate number(s). */ if (atomic_read(&dc->has_dirty) && dc->writeback_percent && !set_at_max_writeback_rate(c, dc)) { do { if (!down_read_trylock((&dc->writeback_lock))) { dc->rate_update_retry++; if (dc->rate_update_retry <= BCH_WBRATE_UPDATE_MAX_SKIPS) break; down_read(&dc->writeback_lock); dc->rate_update_retry = 0; } __update_writeback_rate(dc); update_gc_after_writeback(c); up_read(&dc->writeback_lock); } while (0); }
/* * CACHE_SET_IO_DISABLE might be set via sysfs interface, * check it here too. */ if (test_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags) && !test_bit(CACHE_SET_IO_DISABLE, &c->flags)) { schedule_delayed_work(&dc->writeback_rate_update, dc->writeback_rate_update_seconds * HZ); }
/* * should check BCACHE_DEV_RATE_DW_RUNNING before calling * cancel_delayed_work_sync(). */ clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags); /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */ smp_mb__after_atomic();}
static unsigned int writeback_delay(struct cached_dev *dc, unsigned int sectors){ if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || !dc->writeback_percent) return 0;
return bch_next_delay(&dc->writeback_rate, sectors);}
struct dirty_io { struct closure cl; struct cached_dev *dc; uint16_t sequence; struct bio bio;};
static void dirty_init(struct keybuf_key *w){ struct dirty_io *io = w->private; struct bio *bio = &io->bio;
bio_init_inline(bio, NULL, DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), 0); if (!io->dc->writeback_percent) bio->bi_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
bio->bi_iter.bi_size = KEY_SIZE(&w->key) << 9; bio->bi_private = w; bch_bio_map(bio, NULL);}
static CLOSURE_CALLBACK(dirty_io_destructor){ closure_type(io, struct dirty_io, cl);
kfree(io);}
static CLOSURE_CALLBACK(write_dirty_finish){ closure_type(io, struct dirty_io, cl); struct keybuf_key *w = io->bio.bi_private; struct cached_dev *dc = io->dc;
bio_free_pages(&io->bio);
/* This is kind of a dumb way of signalling errors. */ if (KEY_DIRTY(&w->key)) { int ret; unsigned int i; struct keylist keys;
bch_keylist_init(&keys);
bkey_copy(keys.top, &w->key); SET_KEY_DIRTY(keys.top, false); bch_keylist_push(&keys);
for (i = 0; i < KEY_PTRS(&w->key); i++) atomic_inc(&PTR_BUCKET(dc->disk.c, &w->key, i)->pin);
ret = bch_btree_insert(dc->disk.c, &keys, NULL, &w->key);
if (ret) trace_bcache_writeback_collision(&w->key);
atomic_long_inc(ret ? &dc->disk.c->writeback_keys_failed : &dc->disk.c->writeback_keys_done); }
bch_keybuf_del(&dc->writeback_keys, w); up(&dc->in_flight);
closure_return_with_destructor(cl, dirty_io_destructor);}
static void dirty_endio(struct bio *bio){ struct keybuf_key *w = bio->bi_private; struct dirty_io *io = w->private;
if (bio->bi_status) { SET_KEY_DIRTY(&w->key, false); bch_count_backing_io_errors(io->dc, bio); }
closure_put(&io->cl);}
static CLOSURE_CALLBACK(write_dirty){ closure_type(io, struct dirty_io, cl); struct keybuf_key *w = io->bio.bi_private; struct cached_dev *dc = io->dc;
uint16_t next_sequence;
if (atomic_read(&dc->writeback_sequence_next) != io->sequence) { /* Not our turn to write; wait for a write to complete */ closure_wait(&dc->writeback_ordering_wait, cl);
if (atomic_read(&dc->writeback_sequence_next) == io->sequence) { /* * Edge case-- it happened in indeterminate order * relative to when we were added to wait list.. */ closure_wake_up(&dc->writeback_ordering_wait); }
continue_at(cl, write_dirty, io->dc->writeback_write_wq); return; }
next_sequence = io->sequence + 1;
/* * IO errors are signalled using the dirty bit on the key. * If we failed to read, we should not attempt to write to the * backing device. Instead, immediately go to write_dirty_finish * to clean up. */ if (KEY_DIRTY(&w->key)) { dirty_init(w); io->bio.bi_opf = REQ_OP_WRITE; io->bio.bi_iter.bi_sector = KEY_START(&w->key); bio_set_dev(&io->bio, io->dc->bdev); io->bio.bi_end_io = dirty_endio;
/* I/O request sent to backing device */ closure_bio_submit(io->dc->disk.c, &io->bio, cl); }
atomic_set(&dc->writeback_sequence_next, next_sequence); closure_wake_up(&dc->writeback_ordering_wait);
continue_at(cl, write_dirty_finish, io->dc->writeback_write_wq);}
static void read_dirty_endio(struct bio *bio){ struct keybuf_key *w = bio->bi_private; struct dirty_io *io = w->private;
/* is_read = 1 */ bch_count_io_errors(io->dc->disk.c->cache, bio->bi_status, 1, "reading dirty data from cache");
dirty_endio(bio);}
static CLOSURE_CALLBACK(read_dirty_submit){ closure_type(io, struct dirty_io, cl);
closure_bio_submit(io->dc->disk.c, &io->bio, cl);
continue_at(cl, write_dirty, io->dc->writeback_write_wq);}
static void read_dirty(struct cached_dev *dc){ unsigned int delay = 0; struct keybuf_key *next, *keys[MAX_WRITEBACKS_IN_PASS], *w; size_t size; int nk, i; struct dirty_io *io; struct closure cl; uint16_t sequence = 0;
BUG_ON(!llist_empty(&dc->writeback_ordering_wait.list)); atomic_set(&dc->writeback_sequence_next, sequence); closure_init_stack(&cl);
/* * XXX: if we error, background writeback just spins. Should use some * mempools. */
next = bch_keybuf_next(&dc->writeback_keys);
while (!kthread_should_stop() && !test_bit(CACHE_SET_IO_DISABLE, &dc->disk.c->flags) && next) { size = 0; nk = 0;
do { BUG_ON(ptr_stale(dc->disk.c, &next->key, 0));
/* * Don't combine too many operations, even if they * are all small. */ if (nk >= MAX_WRITEBACKS_IN_PASS) break;
/* * If the current operation is very large, don't * further combine operations. */ if (size >= MAX_WRITESIZE_IN_PASS) break;
/* * Operations are only eligible to be combined * if they are contiguous. * * TODO: add a heuristic willing to fire a * certain amount of non-contiguous IO per pass, * so that we can benefit from backing device * command queueing. */ if ((nk != 0) && bkey_cmp(&keys[nk-1]->key, &START_KEY(&next->key))) break;
size += KEY_SIZE(&next->key); keys[nk++] = next; } while ((next = bch_keybuf_next(&dc->writeback_keys)));
/* Now we have gathered a set of 1..5 keys to write back. */ for (i = 0; i < nk; i++) { w = keys[i];
io = kzalloc(sizeof(*io) + sizeof(struct bio_vec) * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), GFP_KERNEL); if (!io) goto err;
w->private = io; io->dc = dc; io->sequence = sequence++;
dirty_init(w); io->bio.bi_opf = REQ_OP_READ; io->bio.bi_iter.bi_sector = PTR_OFFSET(&w->key, 0); bio_set_dev(&io->bio, dc->disk.c->cache->bdev); io->bio.bi_end_io = read_dirty_endio;
if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL)) goto err_free;
trace_bcache_writeback(&w->key);
down(&dc->in_flight);
/* * We've acquired a semaphore for the maximum * simultaneous number of writebacks; from here * everything happens asynchronously. */ closure_call(&io->cl, read_dirty_submit, NULL, &cl); }
delay = writeback_delay(dc, size);
while (!kthread_should_stop() && !test_bit(CACHE_SET_IO_DISABLE, &dc->disk.c->flags) && delay) { schedule_timeout_interruptible(delay); delay = writeback_delay(dc, 0); } }
if (0) {err_free: kfree(w->private);err: bch_keybuf_del(&dc->writeback_keys, w); }
/* * Wait for outstanding writeback IOs to finish (and keybuf slots to be * freed) before refilling again */ closure_sync(&cl);}
/* Scan for dirty data */
void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode, uint64_t offset, int nr_sectors){ struct bcache_device *d = c->devices[inode]; unsigned int stripe_offset, sectors_dirty; int stripe;
if (!d) return;
stripe = offset_to_stripe(d, offset); if (stripe < 0) return;
if (UUID_FLASH_ONLY(&c->uuids[inode])) atomic_long_add(nr_sectors, &c->flash_dev_dirty_sectors);
stripe_offset = offset & (d->stripe_size - 1);
while (nr_sectors) { int s = min_t(unsigned int, abs(nr_sectors), d->stripe_size - stripe_offset);
if (nr_sectors < 0) s = -s;
if (stripe >= d->nr_stripes) return;
sectors_dirty = atomic_add_return(s, d->stripe_sectors_dirty + stripe); if (sectors_dirty == d->stripe_size) { if (!test_bit(stripe, d->full_dirty_stripes)) set_bit(stripe, d->full_dirty_stripes); } else { if (test_bit(stripe, d->full_dirty_stripes)) clear_bit(stripe, d->full_dirty_stripes); }
nr_sectors -= s; stripe_offset = 0; stripe++; }}
static bool dirty_pred(struct keybuf *buf, struct bkey *k){ struct cached_dev *dc = container_of(buf, struct cached_dev, writeback_keys);
BUG_ON(KEY_INODE(k) != dc->disk.id);
return KEY_DIRTY(k);}
static void refill_full_stripes(struct cached_dev *dc){ struct keybuf *buf = &dc->writeback_keys; unsigned int start_stripe, next_stripe; int stripe; bool wrapped = false;
stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned)); if (stripe < 0) stripe = 0;
start_stripe = stripe;
while (1) { stripe = find_next_bit(dc->disk.full_dirty_stripes, dc->disk.nr_stripes, stripe);
if (stripe == dc->disk.nr_stripes) goto next;
next_stripe = find_next_zero_bit(dc->disk.full_dirty_stripes, dc->disk.nr_stripes, stripe);
buf->last_scanned = KEY(dc->disk.id, stripe * dc->disk.stripe_size, 0);
bch_refill_keybuf(dc->disk.c, buf, &KEY(dc->disk.id, next_stripe * dc->disk.stripe_size, 0), dirty_pred);
if (array_freelist_empty(&buf->freelist)) return;
stripe = next_stripe;next: if (wrapped && stripe > start_stripe) return;
if (stripe == dc->disk.nr_stripes) { stripe = 0; wrapped = true; } }}
/* * Returns true if we scanned the entire disk */static bool refill_dirty(struct cached_dev *dc){ struct keybuf *buf = &dc->writeback_keys; struct bkey start = KEY(dc->disk.id, 0, 0); struct bkey end = KEY(dc->disk.id, MAX_KEY_OFFSET, 0); struct bkey start_pos;
/* * make sure keybuf pos is inside the range for this disk - at bringup * we might not be attached yet so this disk's inode nr isn't * initialized then */ if (bkey_cmp(&buf->last_scanned, &start) < 0 || bkey_cmp(&buf->last_scanned, &end) > 0) buf->last_scanned = start;
if (dc->partial_stripes_expensive) { refill_full_stripes(dc); if (array_freelist_empty(&buf->freelist)) return false; }
start_pos = buf->last_scanned; bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
if (bkey_cmp(&buf->last_scanned, &end) < 0) return false;
/* * If we get to the end start scanning again from the beginning, and * only scan up to where we initially started scanning from: */ buf->last_scanned = start; bch_refill_keybuf(dc->disk.c, buf, &start_pos, dirty_pred);
return bkey_cmp(&buf->last_scanned, &start_pos) >= 0;}
static int bch_writeback_thread(void *arg){ struct cached_dev *dc = arg; struct cache_set *c = dc->disk.c; bool searched_full_index;
bch_ratelimit_reset(&dc->writeback_rate);
while (!kthread_should_stop() && !test_bit(CACHE_SET_IO_DISABLE, &c->flags)) { down_write(&dc->writeback_lock); set_current_state(TASK_INTERRUPTIBLE); /* * If the bache device is detaching, skip here and continue * to perform writeback. Otherwise, if no dirty data on cache, * or there is dirty data on cache but writeback is disabled, * the writeback thread should sleep here and wait for others * to wake up it. */ if (!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) && (!atomic_read(&dc->has_dirty) || !dc->writeback_running)) { up_write(&dc->writeback_lock);
if (kthread_should_stop() || test_bit(CACHE_SET_IO_DISABLE, &c->flags)) { set_current_state(TASK_RUNNING); break; }
schedule(); continue; } set_current_state(TASK_RUNNING);
searched_full_index = refill_dirty(dc);
if (searched_full_index && RB_EMPTY_ROOT(&dc->writeback_keys.keys)) { atomic_set(&dc->has_dirty, 0); SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN); bch_write_bdev_super(dc, NULL); /* * If bcache device is detaching via sysfs interface, * writeback thread should stop after there is no dirty * data on cache. BCACHE_DEV_DETACHING flag is set in * bch_cached_dev_detach(). */ if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) { struct closure cl;
closure_init_stack(&cl); memset(&dc->sb.set_uuid, 0, 16); SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
bch_write_bdev_super(dc, &cl); closure_sync(&cl);
up_write(&dc->writeback_lock); break; }
/* * When dirty data rate is high (e.g. 50%+), there might * be heavy buckets fragmentation after writeback * finished, which hurts following write performance. * If users really care about write performance they * may set BCH_ENABLE_AUTO_GC via sysfs, then when * BCH_DO_AUTO_GC is set, garbage collection thread * will be wake up here. After moving gc, the shrunk * btree may be helpful for following write requests. */ if (c->gc_after_writeback == (BCH_ENABLE_AUTO_GC|BCH_DO_AUTO_GC)) { c->gc_after_writeback &= ~BCH_DO_AUTO_GC; force_wake_up_gc(c); } }
up_write(&dc->writeback_lock);
read_dirty(dc);
if (searched_full_index) { unsigned int delay = dc->writeback_delay * HZ;
while (delay && !kthread_should_stop() && !test_bit(CACHE_SET_IO_DISABLE, &c->flags) && !test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) delay = schedule_timeout_interruptible(delay);
bch_ratelimit_reset(&dc->writeback_rate); } }
if (dc->writeback_write_wq) destroy_workqueue(dc->writeback_write_wq);
cached_dev_put(dc); wait_for_kthread_stop();
return 0;}
/* Init */#define INIT_KEYS_EACH_TIME 500000
struct sectors_dirty_init { struct btree_op op; unsigned int inode; size_t count;};
static int sectors_dirty_init_fn(struct btree_op *_op, struct btree *b, struct bkey *k){ struct sectors_dirty_init *op = container_of(_op, struct sectors_dirty_init, op); if (KEY_INODE(k) > op->inode) return MAP_DONE;
if (KEY_DIRTY(k)) bcache_dev_sectors_dirty_add(b->c, KEY_INODE(k), KEY_START(k), KEY_SIZE(k));
op->count++; if (!(op->count % INIT_KEYS_EACH_TIME)) cond_resched();
return MAP_CONTINUE;}
static int bch_root_node_dirty_init(struct cache_set *c, struct bcache_device *d, struct bkey *k){ struct sectors_dirty_init op; int ret;
bch_btree_op_init(&op.op, -1); op.inode = d->id; op.count = 0;
ret = bcache_btree(map_keys_recurse, k, c->root, &op.op, &KEY(op.inode, 0, 0), sectors_dirty_init_fn, 0); if (ret < 0) pr_warn("sectors dirty init failed, ret=%d!\n", ret);
/* * The op may be added to cache_set's btree_cache_wait * in mca_cannibalize(), must ensure it is removed from * the list and release btree_cache_alloc_lock before * free op memory. * Otherwise, the btree_cache_wait will be damaged. */ bch_cannibalize_unlock(c); finish_wait(&c->btree_cache_wait, &(&op.op)->wait);
return ret;}
static int bch_dirty_init_thread(void *arg){ struct dirty_init_thrd_info *info = arg; struct bch_dirty_init_state *state = info->state; struct cache_set *c = state->c; struct btree_iter_stack iter; struct bkey *k, *p; int cur_idx, prev_idx, skip_nr;
k = p = NULL; prev_idx = 0;
bch_btree_iter_stack_init(&c->root->keys, &iter, NULL); k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); BUG_ON(!k);
p = k;
while (k) { spin_lock(&state->idx_lock); cur_idx = state->key_idx; state->key_idx++; spin_unlock(&state->idx_lock);
skip_nr = cur_idx - prev_idx;
while (skip_nr) { k = bch_btree_iter_next_filter(&iter.iter, &c->root->keys, bch_ptr_bad); if (k) p = k; else { atomic_set(&state->enough, 1); /* Update state->enough earlier */ smp_mb__after_atomic(); goto out; } skip_nr--; }
if (p) { if (bch_root_node_dirty_init(c, state->d, p) < 0) goto out; }
p = NULL; prev_idx = cur_idx; }
out: /* In order to wake up state->wait in time */ smp_mb__before_atomic(); if (atomic_dec_and_test(&state->started)) wake_up(&state->wait);
return 0;}
static int bch_btre_dirty_init_thread_nr(void){ int n = num_online_cpus()/2;
if (n == 0) n = 1; else if (n > BCH_DIRTY_INIT_THRD_MAX) n = BCH_DIRTY_INIT_THRD_MAX;
return n;}
void bch_sectors_dirty_init(struct bcache_device *d){ int i; struct btree *b = NULL; struct bkey *k = NULL; struct btree_iter_stack iter; struct sectors_dirty_init op; struct cache_set *c = d->c; struct bch_dirty_init_state state;
retry_lock: b = c->root; rw_lock(0, b, b->level); if (b != c->root) { rw_unlock(0, b); goto retry_lock; }
/* Just count root keys if no leaf node */ if (c->root->level == 0) { bch_btree_op_init(&op.op, -1); op.inode = d->id; op.count = 0;
for_each_key_filter(&c->root->keys, k, &iter, bch_ptr_invalid) { if (KEY_INODE(k) != op.inode) continue; sectors_dirty_init_fn(&op.op, c->root, k); }
rw_unlock(0, b); return; }
memset(&state, 0, sizeof(struct bch_dirty_init_state)); state.c = c; state.d = d; state.total_threads = bch_btre_dirty_init_thread_nr(); state.key_idx = 0; spin_lock_init(&state.idx_lock); atomic_set(&state.started, 0); atomic_set(&state.enough, 0); init_waitqueue_head(&state.wait);
for (i = 0; i < state.total_threads; i++) { /* Fetch latest state.enough earlier */ smp_mb__before_atomic(); if (atomic_read(&state.enough)) break;
atomic_inc(&state.started); state.infos[i].state = &state; state.infos[i].thread = kthread_run(bch_dirty_init_thread, &state.infos[i], "bch_dirtcnt[%d]", i); if (IS_ERR(state.infos[i].thread)) { pr_err("fails to run thread bch_dirty_init[%d]\n", i); atomic_dec(&state.started); for (--i; i >= 0; i--) kthread_stop(state.infos[i].thread); goto out; } }
out: /* Must wait for all threads to stop. */ wait_event(state.wait, atomic_read(&state.started) == 0); rw_unlock(0, b);}
void bch_cached_dev_writeback_init(struct cached_dev *dc){ sema_init(&dc->in_flight, 64); init_rwsem(&dc->writeback_lock); bch_keybuf_init(&dc->writeback_keys);
dc->writeback_metadata = true; dc->writeback_running = false; dc->writeback_consider_fragment = true; dc->writeback_percent = 10; dc->writeback_delay = 30; atomic_long_set(&dc->writeback_rate.rate, 1024); dc->writeback_rate_minimum = 8;
dc->writeback_rate_update_seconds = WRITEBACK_RATE_UPDATE_SECS_DEFAULT; dc->writeback_rate_p_term_inverse = 40; dc->writeback_rate_fp_term_low = 1; dc->writeback_rate_fp_term_mid = 10; dc->writeback_rate_fp_term_high = 1000; dc->writeback_rate_i_term_inverse = 10000;
/* For dc->writeback_lock contention in update_writeback_rate() */ dc->rate_update_retry = 0;
WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)); INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate);}
int bch_cached_dev_writeback_start(struct cached_dev *dc){ dc->writeback_write_wq = alloc_workqueue("bcache_writeback_wq", WQ_MEM_RECLAIM | WQ_PERCPU, 0); if (!dc->writeback_write_wq) return -ENOMEM;
cached_dev_get(dc); dc->writeback_thread = kthread_create(bch_writeback_thread, dc, "bcache_writeback"); if (IS_ERR(dc->writeback_thread)) { cached_dev_put(dc); destroy_workqueue(dc->writeback_write_wq); return PTR_ERR(dc->writeback_thread); } dc->writeback_running = true;
WARN_ON(test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)); schedule_delayed_work(&dc->writeback_rate_update, dc->writeback_rate_update_seconds * HZ);
bch_writeback_queue(dc);
return 0;}