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[Qemu-block] [PATCH v3 02/39] qcow2: Add table size field to Qcow2Cache
From: |
Alberto Garcia |
Subject: |
[Qemu-block] [PATCH v3 02/39] qcow2: Add table size field to Qcow2Cache |
Date: |
Fri, 26 Jan 2018 16:59:29 +0200 |
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 <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
block/qcow2-cache.c | 29 ++++++++++++++---------------
1 file 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;
}
--
2.11.0
- [Qemu-block] [PATCH v3 00/39] Allow configuring the qcow2 L2 cache entry size, Alberto Garcia, 2018/01/26
- [Qemu-block] [PATCH v3 16/39] qcow2: Prepare l2_allocate() for adding L2 slice support, Alberto Garcia, 2018/01/26
- [Qemu-block] [PATCH v3 02/39] qcow2: Add table size field to Qcow2Cache,
Alberto Garcia <=
- [Qemu-block] [PATCH v3 15/39] qcow2: Update l2_load() to support L2 slices, Alberto Garcia, 2018/01/26
- [Qemu-block] [PATCH v3 18/39] qcow2: Refactor get_cluster_table(), Alberto Garcia, 2018/01/26
- [Qemu-block] [PATCH v3 03/39] qcow2: Remove BDS parameter from qcow2_cache_get_table_addr(), Alberto Garcia, 2018/01/26
- [Qemu-block] [PATCH v3 12/39] qcow2: Add offset_to_l1_index(), Alberto Garcia, 2018/01/26