--- /dev/null
+/*
+ * Moving/copying garbage collector
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <trace/events/bcache.h>
+
+struct moving_io {
+ struct closure cl;
+ struct keybuf_key *w;
+ struct data_insert_op op;
+ struct bbio bio;
+};
+
+static bool moving_pred(struct keybuf *buf, struct bkey *k)
+{
+ struct cache_set *c = container_of(buf, struct cache_set,
+ moving_gc_keys);
+ unsigned i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i) &&
+ GC_MOVE(PTR_BUCKET(c, k, i)))
+ return true;
+
+ return false;
+}
+
+/* Moving GC - IO loop */
+
+static void moving_io_destructor(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, cl);
+ kfree(io);
+}
+
+static void write_moving_finish(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, cl);
+ struct bio *bio = &io->bio.bio;
+ struct bio_vec *bv;
+ int i;
+
+ bio_for_each_segment_all(bv, bio, i)
+ __free_page(bv->bv_page);
+
+ if (io->op.replace_collision)
+ trace_bcache_gc_copy_collision(&io->w->key);
+
+ bch_keybuf_del(&io->op.c->moving_gc_keys, io->w);
+
+ up(&io->op.c->moving_in_flight);
+
+ closure_return_with_destructor(cl, moving_io_destructor);
+}
+
+static void read_moving_endio(struct bio *bio, int error)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+ struct moving_io *io = container_of(bio->bi_private,
+ struct moving_io, cl);
+
+ if (error)
+ io->op.error = error;
+ else if (!KEY_DIRTY(&b->key) &&
+ ptr_stale(io->op.c, &b->key, 0)) {
+ io->op.error = -EINTR;
+ }
+
+ bch_bbio_endio(io->op.c, bio, error, "reading data to move");
+}
+
+static void moving_init(struct moving_io *io)
+{
+ struct bio *bio = &io->bio.bio;
+
+ bio_init(bio);
+ bio_get(bio);
+ bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+ bio->bi_iter.bi_size = KEY_SIZE(&io->w->key) << 9;
+ bio->bi_max_vecs = DIV_ROUND_UP(KEY_SIZE(&io->w->key),
+ PAGE_SECTORS);
+ bio->bi_private = &io->cl;
+ bio->bi_io_vec = bio->bi_inline_vecs;
+ bch_bio_map(bio, NULL);
+}
+
+static void write_moving(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, cl);
+ struct data_insert_op *op = &io->op;
+
+ if (!op->error) {
+ moving_init(io);
+
+ io->bio.bio.bi_iter.bi_sector = KEY_START(&io->w->key);
+ op->write_prio = 1;
+ op->bio = &io->bio.bio;
+
+ op->writeback = KEY_DIRTY(&io->w->key);
+ op->csum = KEY_CSUM(&io->w->key);
+
+ bkey_copy(&op->replace_key, &io->w->key);
+ op->replace = true;
+
+ closure_call(&op->cl, bch_data_insert, NULL, cl);
+ }
+
+ continue_at(cl, write_moving_finish, op->wq);
+}
+
+static void read_moving_submit(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, cl);
+ struct bio *bio = &io->bio.bio;
+
+ bch_submit_bbio(bio, io->op.c, &io->w->key, 0);
+
+ continue_at(cl, write_moving, io->op.wq);
+}
+
+static void read_moving(struct cache_set *c)
+{
+ struct keybuf_key *w;
+ struct moving_io *io;
+ struct bio *bio;
+ struct closure cl;
+
+ closure_init_stack(&cl);
+
+ /* XXX: if we error, background writeback could stall indefinitely */
+
+ while (!test_bit(CACHE_SET_STOPPING, &c->flags)) {
+ w = bch_keybuf_next_rescan(c, &c->moving_gc_keys,
+ &MAX_KEY, moving_pred);
+ if (!w)
+ break;
+
+ if (ptr_stale(c, &w->key, 0)) {
+ bch_keybuf_del(&c->moving_gc_keys, w);
+ continue;
+ }
+
+ io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec)
+ * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS),
+ GFP_KERNEL);
+ if (!io)
+ goto err;
+
+ w->private = io;
+ io->w = w;
+ io->op.inode = KEY_INODE(&w->key);
+ io->op.c = c;
+ io->op.wq = c->moving_gc_wq;
+
+ moving_init(io);
+ bio = &io->bio.bio;
+
+ bio->bi_rw = READ;
+ bio->bi_end_io = read_moving_endio;
+
+ if (bio_alloc_pages(bio, GFP_KERNEL))
+ goto err;
+
+ trace_bcache_gc_copy(&w->key);
+
+ down(&c->moving_in_flight);
+ closure_call(&io->cl, read_moving_submit, NULL, &cl);
+ }
+
+ if (0) {
+err: if (!IS_ERR_OR_NULL(w->private))
+ kfree(w->private);
+
+ bch_keybuf_del(&c->moving_gc_keys, w);
+ }
+
+ closure_sync(&cl);
+}
+
+static bool bucket_cmp(struct bucket *l, struct bucket *r)
+{
+ return GC_SECTORS_USED(l) < GC_SECTORS_USED(r);
+}
+
+static unsigned bucket_heap_top(struct cache *ca)
+{
+ struct bucket *b;
+ return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0;
+}
+
+void bch_moving_gc(struct cache_set *c)
+{
+ struct cache *ca;
+ struct bucket *b;
+ unsigned i;
+
+ if (!c->copy_gc_enabled)
+ return;
+
+ mutex_lock(&c->bucket_lock);
+
+ for_each_cache(ca, c, i) {
+ unsigned sectors_to_move = 0;
+ unsigned reserve_sectors = ca->sb.bucket_size *
+ fifo_used(&ca->free[RESERVE_MOVINGGC]);
+
+ ca->heap.used = 0;
+
+ for_each_bucket(b, ca) {
+ if (GC_MARK(b) == GC_MARK_METADATA ||
+ !GC_SECTORS_USED(b) ||
+ GC_SECTORS_USED(b) == ca->sb.bucket_size ||
+ atomic_read(&b->pin))
+ continue;
+
+ if (!heap_full(&ca->heap)) {
+ sectors_to_move += GC_SECTORS_USED(b);
+ heap_add(&ca->heap, b, bucket_cmp);
+ } else if (bucket_cmp(b, heap_peek(&ca->heap))) {
+ sectors_to_move -= bucket_heap_top(ca);
+ sectors_to_move += GC_SECTORS_USED(b);
+
+ ca->heap.data[0] = b;
+ heap_sift(&ca->heap, 0, bucket_cmp);
+ }
+ }
+
+ while (sectors_to_move > reserve_sectors) {
+ heap_pop(&ca->heap, b, bucket_cmp);
+ sectors_to_move -= GC_SECTORS_USED(b);
+ }
+
+ while (heap_pop(&ca->heap, b, bucket_cmp))
+ SET_GC_MOVE(b, 1);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+
+ c->moving_gc_keys.last_scanned = ZERO_KEY;
+
+ read_moving(c);
+}
+
+void bch_moving_init_cache_set(struct cache_set *c)
+{
+ bch_keybuf_init(&c->moving_gc_keys);
+ sema_init(&c->moving_in_flight, 64);
+}
Code Review / kvmfornfv.git / blobdiff