diff options
Diffstat (limited to 'qemu/block/qcow2-cache.c')
| -rw-r--r-- | qemu/block/qcow2-cache.c | 85 |
1 files changed, 73 insertions, 12 deletions
diff --git a/qemu/block/qcow2-cache.c b/qemu/block/qcow2-cache.c index 53b8afc3d..0fe8edae4 100644 --- a/qemu/block/qcow2-cache.c +++ b/qemu/block/qcow2-cache.c @@ -22,6 +22,13 @@ * THE SOFTWARE. */ +/* Needed for CONFIG_MADVISE */ +#include "qemu/osdep.h" + +#if defined(CONFIG_MADVISE) || defined(CONFIG_POSIX_MADVISE) +#include <sys/mman.h> +#endif + #include "block/block_int.h" #include "qemu-common.h" #include "qcow2.h" @@ -29,9 +36,9 @@ typedef struct Qcow2CachedTable { int64_t offset; - bool dirty; uint64_t lru_counter; int ref; + bool dirty; } Qcow2CachedTable; struct Qcow2Cache { @@ -41,34 +48,85 @@ struct Qcow2Cache { bool depends_on_flush; void *table_array; uint64_t lru_counter; + uint64_t cache_clean_lru_counter; }; static inline void *qcow2_cache_get_table_addr(BlockDriverState *bs, Qcow2Cache *c, int table) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; return (uint8_t *) c->table_array + (size_t) table * s->cluster_size; } static inline int qcow2_cache_get_table_idx(BlockDriverState *bs, Qcow2Cache *c, void *table) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; ptrdiff_t table_offset = (uint8_t *) table - (uint8_t *) c->table_array; int idx = table_offset / s->cluster_size; assert(idx >= 0 && idx < c->size && table_offset % s->cluster_size == 0); return idx; } +static void qcow2_cache_table_release(BlockDriverState *bs, Qcow2Cache *c, + int i, int num_tables) +{ +#if QEMU_MADV_DONTNEED != QEMU_MADV_INVALID + BDRVQcow2State *s = bs->opaque; + void *t = qcow2_cache_get_table_addr(bs, c, i); + int align = getpagesize(); + size_t mem_size = (size_t) s->cluster_size * num_tables; + size_t offset = QEMU_ALIGN_UP((uintptr_t) t, align) - (uintptr_t) t; + size_t length = QEMU_ALIGN_DOWN(mem_size - offset, align); + if (length > 0) { + qemu_madvise((uint8_t *) t + offset, length, QEMU_MADV_DONTNEED); + } +#endif +} + +static inline bool can_clean_entry(Qcow2Cache *c, int i) +{ + Qcow2CachedTable *t = &c->entries[i]; + return t->ref == 0 && !t->dirty && t->offset != 0 && + t->lru_counter <= c->cache_clean_lru_counter; +} + +void qcow2_cache_clean_unused(BlockDriverState *bs, Qcow2Cache *c) +{ + int i = 0; + while (i < c->size) { + int to_clean = 0; + + /* Skip the entries that we don't need to clean */ + while (i < c->size && !can_clean_entry(c, i)) { + i++; + } + + /* And count how many we can clean in a row */ + while (i < c->size && can_clean_entry(c, i)) { + c->entries[i].offset = 0; + c->entries[i].lru_counter = 0; + i++; + to_clean++; + } + + if (to_clean > 0) { + qcow2_cache_table_release(bs, c, i - to_clean, to_clean); + } + } + + c->cache_clean_lru_counter = c->lru_counter; +} + Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; Qcow2Cache *c; c = g_new0(Qcow2Cache, 1); c->size = num_tables; c->entries = g_try_new0(Qcow2CachedTable, num_tables); - c->table_array = qemu_try_blockalign(bs->file, + c->table_array = qemu_try_blockalign(bs->file->bs, (size_t) num_tables * s->cluster_size); if (!c->entries || !c->table_array) { @@ -113,7 +171,7 @@ static int qcow2_cache_flush_dependency(BlockDriverState *bs, Qcow2Cache *c) static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; int ret = 0; if (!c->entries[i].dirty || !c->entries[i].offset) { @@ -126,7 +184,7 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i) if (c->depends) { ret = qcow2_cache_flush_dependency(bs, c); } else if (c->depends_on_flush) { - ret = bdrv_flush(bs->file); + ret = bdrv_flush(bs->file->bs); if (ret >= 0) { c->depends_on_flush = false; } @@ -157,7 +215,7 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i) BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); } - ret = bdrv_pwrite(bs->file, c->entries[i].offset, + ret = bdrv_pwrite(bs->file->bs, c->entries[i].offset, qcow2_cache_get_table_addr(bs, c, i), s->cluster_size); if (ret < 0) { return ret; @@ -170,7 +228,7 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i) int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; int result = 0; int ret; int i; @@ -185,7 +243,7 @@ int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c) } if (result == 0) { - ret = bdrv_flush(bs->file); + ret = bdrv_flush(bs->file->bs); if (ret < 0) { result = ret; } @@ -237,6 +295,8 @@ int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c) c->entries[i].lru_counter = 0; } + qcow2_cache_table_release(bs, c, 0, c->size); + c->lru_counter = 0; return 0; @@ -245,7 +305,7 @@ int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c) static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, void **table, bool read_from_disk) { - BDRVQcowState *s = bs->opaque; + BDRVQcow2State *s = bs->opaque; int i; int ret; int lookup_index; @@ -295,7 +355,8 @@ static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c, BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); } - ret = bdrv_pread(bs->file, offset, qcow2_cache_get_table_addr(bs, c, i), + ret = bdrv_pread(bs->file->bs, offset, + qcow2_cache_get_table_addr(bs, c, i), s->cluster_size); if (ret < 0) { return ret; |