diff options
| -rw-r--r-- | block/qcow2-cache.c | 45 |
1 files changed, 16 insertions, 29 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c index 3a31895..2035cd8 100644 --- a/block/qcow2-cache.c +++ b/block/qcow2-cache.c @@ -242,51 +242,38 @@ int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c) return 0; } -static int qcow2_cache_find_entry_to_replace(Qcow2Cache *c) -{ - int i; - uint64_t min_lru_counter = UINT64_MAX; - int min_index = -1; - - - for (i = 0; i < c->size; i++) { - if (c->entries[i].ref) { - continue; - } - - if (c->entries[i].lru_counter < min_lru_counter) { - min_index = i; - min_lru_counter = c->entries[i].lru_counter; - } - } - - if (min_index == -1) { - /* This can't happen in current synchronous code, but leave the check - * here as a reminder for whoever starts using AIO with the cache */ - abort(); - } - return min_index; -} - static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, void **table, bool read_from_disk) { BDRVQcowState *s = bs->opaque; int i; int ret; + uint64_t min_lru_counter = UINT64_MAX; + int min_lru_index = -1; trace_qcow2_cache_get(qemu_coroutine_self(), c == s->l2_table_cache, offset, read_from_disk); /* Check if the table is already cached */ for (i = 0; i < c->size; i++) { - if (c->entries[i].offset == offset) { + const Qcow2CachedTable *t = &c->entries[i]; + if (t->offset == offset) { goto found; } + if (t->ref == 0 && t->lru_counter < min_lru_counter) { + min_lru_counter = t->lru_counter; + min_lru_index = i; + } + } + + if (min_lru_index == -1) { + /* This can't happen in current synchronous code, but leave the check + * here as a reminder for whoever starts using AIO with the cache */ + abort(); } - /* If not, write a table back and replace it */ - i = qcow2_cache_find_entry_to_replace(c); + /* Cache miss: write a table back and replace it */ + i = min_lru_index; trace_qcow2_cache_get_replace_entry(qemu_coroutine_self(), c == s->l2_table_cache, i); if (i < 0) { |