if the next block is cached, then we need to check the size of node to
ensure full readahead.
Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com>
---
block/pcache.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 49 insertions(+), 2 deletions(-)
diff --git a/block/pcache.c b/block/pcache.c
index 90b3f85..ae7ac8d 100644
--- a/block/pcache.c
+++ b/block/pcache.c
@@ -427,6 +427,16 @@ static bool pcache_node_find_and_create(PrefCacheAIOCB
*acb, RbNodeKey *key,
return true;
}
+static inline PCNode *pcache_node_add(PrefCacheAIOCB *acb, RbNodeKey *key)
+{
+ PCNode *node = NULL;
+ if (!pcache_node_find_and_create(acb, key, &node)) {
+ pcache_node_unref(acb->s, node);
+ return NULL;
+ }
+ return node;
+}
+
static uint64_t ranges_overlap_size(uint64_t node1, uint32_t size1,
uint64_t node2, uint32_t size2)
{
@@ -735,6 +745,38 @@ static void pcache_send_acb_request_list(BlockDriverState
*bs,
qemu_co_mutex_unlock(&acb->requests.lock);
}
+static void readahead_node_prev(PrefCacheAIOCB *acb, PCNode *node,
+ RbNodeKey *key)
+{
+ RbNodeKey lc_key;
+ if (node->cm.key.num <= key->num) {
+ return;
+ }
+
+ lc_key.num = key->num;
+ lc_key.size = node->cm.key.num - key->num;
+
+ pcache_node_add(acb, &lc_key);
+}
+
+static void readahead_node_next(PrefCacheAIOCB *acb, PCNode *node,
+ RbNodeKey *key, uint64_t total_sectors)
+{
+ BDRVPCacheState *s;
+ RbNodeKey lc_key;
+ if (node->cm.key.num + node->cm.key.size >= key->num + key->size) {
+ return;
+ }
+ s = acb->s;
+
+ lc_key.num = node->cm.key.num + node->cm.key.size;
+ lc_key.size = s->cfg.readahead_size;
+ if (total_sectors <= lc_key.num + lc_key.size) {
+ return;
+ }
+ pcache_node_add(acb, &lc_key);
+}
+
static bool check_allocated_blocks(BlockDriverState *bs, int64_t sector_num,
int32_t nb_sectors)
{
@@ -777,9 +819,14 @@ static void pcache_readahead_request(BlockDriverState *bs,
PrefCacheAIOCB *acb)
acb->common.opaque, PCACHE_AIO_READ |
PCACHE_AIO_READAHEAD);
if (!pcache_node_find_and_create(acb_readahead, &key, &node)) {
+ readahead_node_prev(acb_readahead, node, &key);
+ readahead_node_next(acb_readahead, node, &key, total_sectors);
+
pcache_node_unref(s, node);
- qemu_aio_unref(acb_readahead);
- return;
+ if (acb_readahead->requests.cnt == 0) {
+ qemu_aio_unref(acb_readahead);
+ return;
+ }
}
pcache_send_acb_request_list(bs, acb_readahead);
}
--
2.8.3
