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authorAlberto Garcia <berto@igalia.com>2018-02-05 16:33:02 +0200
committerMax Reitz <mreitz@redhat.com>2018-02-13 16:59:58 +0100
commit03019d73142f78c22b87b7162f3c4a390d7d839e (patch)
treeafd5ee7fec5ee6a589329959559009a2f32ad967 /block
parentd4c373b854f813a6c3b9f763c98723053aa80ac5 (diff)
qcow2: Add table size field to Qcow2Cache
The table size in the qcow2 cache is currently equal to the cluster size. This doesn't allow us to use the cache memory efficiently, particularly with large cluster sizes, so we need to be able to have smaller cache tables that are independent from the cluster size. This patch adds a new field to Qcow2Cache that we can use instead of the cluster size. The current table size is still being initialized to the cluster size, so there are no semantic changes yet, but this patch will allow us to prepare the rest of the code and simplify a few function calls. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 67a1bf9e55f417005c567bead95a018dc34bc687.1517840876.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/qcow2-cache.c29
1 files changed, 14 insertions, 15 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index c48ffebd8f..38c03770b4 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -39,6 +39,7 @@ struct Qcow2Cache {
Qcow2CachedTable *entries;
struct Qcow2Cache *depends;
int size;
+ int table_size;
bool depends_on_flush;
void *table_array;
uint64_t lru_counter;
@@ -48,17 +49,15 @@ struct Qcow2Cache {
static inline void *qcow2_cache_get_table_addr(BlockDriverState *bs,
Qcow2Cache *c, int table)
{
- BDRVQcow2State *s = bs->opaque;
- return (uint8_t *) c->table_array + (size_t) table * s->cluster_size;
+ return (uint8_t *) c->table_array + (size_t) table * c->table_size;
}
static inline int qcow2_cache_get_table_idx(BlockDriverState *bs,
Qcow2Cache *c, void *table)
{
- 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);
+ int idx = table_offset / c->table_size;
+ assert(idx >= 0 && idx < c->size && table_offset % c->table_size == 0);
return idx;
}
@@ -79,10 +78,9 @@ static void qcow2_cache_table_release(BlockDriverState *bs, Qcow2Cache *c,
{
/* Using MADV_DONTNEED to discard memory is a Linux-specific feature */
#ifdef CONFIG_LINUX
- 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 mem_size = (size_t) c->table_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 (mem_size > offset && length > 0) {
@@ -132,9 +130,10 @@ Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables)
c = g_new0(Qcow2Cache, 1);
c->size = num_tables;
+ c->table_size = s->cluster_size;
c->entries = g_try_new0(Qcow2CachedTable, num_tables);
c->table_array = qemu_try_blockalign(bs->file->bs,
- (size_t) num_tables * s->cluster_size);
+ (size_t) num_tables * c->table_size);
if (!c->entries || !c->table_array) {
qemu_vfree(c->table_array);
@@ -203,13 +202,13 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
if (c == s->refcount_block_cache) {
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_REFCOUNT_BLOCK,
- c->entries[i].offset, s->cluster_size);
+ c->entries[i].offset, c->table_size);
} else if (c == s->l2_table_cache) {
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
- c->entries[i].offset, s->cluster_size);
+ c->entries[i].offset, c->table_size);
} else {
ret = qcow2_pre_write_overlap_check(bs, 0,
- c->entries[i].offset, s->cluster_size);
+ c->entries[i].offset, c->table_size);
}
if (ret < 0) {
@@ -223,7 +222,7 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
}
ret = bdrv_pwrite(bs->file, c->entries[i].offset,
- qcow2_cache_get_table_addr(bs, c, i), s->cluster_size);
+ qcow2_cache_get_table_addr(bs, c, i), c->table_size);
if (ret < 0) {
return ret;
}
@@ -331,7 +330,7 @@ static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c,
trace_qcow2_cache_get(qemu_coroutine_self(), c == s->l2_table_cache,
offset, read_from_disk);
- if (offset_into_cluster(s, offset)) {
+ if (!QEMU_IS_ALIGNED(offset, c->table_size)) {
qcow2_signal_corruption(bs, true, -1, -1, "Cannot get entry from %s "
"cache: Offset %#" PRIx64 " is unaligned",
qcow2_cache_get_name(s, c), offset);
@@ -339,7 +338,7 @@ static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c,
}
/* Check if the table is already cached */
- i = lookup_index = (offset / s->cluster_size * 4) % c->size;
+ i = lookup_index = (offset / c->table_size * 4) % c->size;
do {
const Qcow2CachedTable *t = &c->entries[i];
if (t->offset == offset) {
@@ -380,7 +379,7 @@ static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c,
ret = bdrv_pread(bs->file, offset,
qcow2_cache_get_table_addr(bs, c, i),
- s->cluster_size);
+ c->table_size);
if (ret < 0) {
return ret;
}