qemu/block
Alberto Garcia 8e8cb375e0 block: Give always priority to unused entries in the qcow2 L2 cache
The current algorithm to replace entries from the L2 cache gives
priority to newer hits by dividing the hit count of all existing
entries by two everytime there is a cache miss.

However, if there are several cache misses the hit count of the
existing entries can easily go down to 0. This will result in those
entries being replaced even when there are others that have never been
used.

This problem is more noticeable with larger disk images and cache
sizes, since the chances of having several misses before the cache is
full are higher.

If we make sure that the hit count can never go down to 0 again,
unused entries will always have priority.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:22 +01:00
..
accounting.c block: add accounting for merged requests 2015-02-06 17:24:21 +01:00
archipelago.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
backup.c qmp: Add command 'blockdev-backup' 2015-01-13 11:47:56 +00:00
blkdebug.c blkdebug: Simplify and improve filename generation 2014-12-10 10:31:11 +01:00
blkverify.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
block-backend.c block-backend: expose bs->bl.max_transfer_length 2015-02-06 17:24:21 +01:00
bochs.c block: Use g_new() & friends to avoid multiplying sizes 2014-08-20 11:51:28 +02:00
cloop.c cloop: Handle failure for potentially large allocations 2014-08-15 15:07:15 +02:00
commit.c block: let commit blockjob run in BDS AioContext 2014-11-03 11:41:49 +00:00
curl.c block/curl: Improve type safety of s->timeout. 2014-11-03 11:41:47 +00:00
dmg.c block/dmg: improve zeroes handling 2015-02-06 17:24:21 +01:00
gluster.c block: don't convert file size to sector size 2014-09-12 15:43:06 +02:00
iscsi.c block/iscsi: fix uninitialized variable 2015-01-03 09:22:13 +01:00
linux-aio.c linux-aio: simplify removal of completed iocbs from the list 2014-12-12 16:57:55 +00:00
Makefile.objs block/dmg: support bzip2 block entry types 2015-02-06 17:24:21 +01:00
mirror.c block: mirror - change string allocation to 2-bytes 2015-01-23 18:17:06 +01:00
nbd-client.c nbd: Improve error messages 2015-02-06 17:24:22 +01:00
nbd-client.h nbd: Improve error messages 2015-02-06 17:24:22 +01:00
nbd.c nbd: fix max_discard/max_transfer_length 2015-02-06 17:24:22 +01:00
nfs.c block/nfs: Add create_opts 2014-12-10 10:31:19 +01:00
null.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
parallels.c block/parallels: fix access to not initialized memory in catalog_bitmap 2014-11-03 09:48:41 +00:00
qapi.c block: add event when disk usage exceeds threshold 2015-02-06 17:24:21 +01:00
qcow2-cache.c block: Give always priority to unused entries in the qcow2 L2 cache 2015-02-06 17:24:22 +01:00
qcow2-cluster.c qcow2: Add two more unalignment checks 2015-01-23 18:17:05 +01:00
qcow2-refcount.c block/qcow2: Make get_refcount() global 2014-11-03 11:41:49 +00:00
qcow2-snapshot.c qcow2: Allow "full" discard 2014-11-03 11:41:47 +00:00
qcow2.c block: fix off-by-one error in qcow and qcow2 2015-02-06 17:24:21 +01:00
qcow2.h block/qcow2: Make get_refcount() global 2014-11-03 11:41:49 +00:00
qcow.c block: fix off-by-one error in qcow and qcow2 2015-02-06 17:24:21 +01:00
qed-check.c block: Use g_new() & friends to avoid multiplying sizes 2014-08-20 11:51:28 +02:00
qed-cluster.c
qed-gencb.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
qed-l2-cache.c
qed-table.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
qed.c qed: check for header size overflow 2015-02-06 17:24:21 +01:00
qed.h qed: Really remove unused field QEDAIOCB.finished 2015-02-06 17:24:21 +01:00
quorum.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
raw_bsd.c block: Make essential BlockDriver objects public 2014-12-10 10:31:19 +01:00
raw-aio.h linux-aio: drop return code from laio_io_unplug and ioq_submit 2014-12-12 16:57:55 +00:00
raw-posix.c block: use fallocate(FALLOC_FL_PUNCH_HOLE) & fallocate(0) to write zeroes 2015-02-06 17:24:20 +01:00
raw-win32.c block: Make essential BlockDriver objects public 2014-12-10 10:31:19 +01:00
rbd.c block/rbd: fix memory leak 2014-12-12 13:16:56 +00:00
sheepdog.c block: Rename BlockDriverAIOCB* to BlockAIOCB* 2014-10-20 13:41:27 +02:00
snapshot.c snapshot: add bdrv_drain_all() to bdrv_snapshot_delete() to avoid concurrency problem 2014-11-03 09:48:42 +00:00
ssh.c ssh: Don't crash if either host or path is not specified. 2014-10-03 10:30:33 +01:00
stream.c block: let stream blockjob run in BDS AioContext 2014-11-03 11:41:49 +00:00
vdi.c block: remove BLOCK_OPT_NOCOW from vdi_create_opts 2014-12-10 10:31:20 +01:00
vhdx-endian.c block: VHDX endian fixes 2014-08-15 15:07:14 +02:00
vhdx-log.c block: Drop some superfluous casts from void * 2014-08-20 11:51:28 +02:00
vhdx.c block: vhdx - force FileOffsetMB field to '0' for certain block states 2015-01-23 12:41:32 -05:00
vhdx.h block: vhdx - update PAYLOAD_BLOCK_UNMAPPED value to match 1.00 spec 2014-12-12 15:42:22 +00:00
vmdk.c block: vmdk - move string allocations from stack to the heap 2015-01-23 18:17:05 +01:00
vpc.c block: remove BLOCK_OPT_NOCOW from vpc_create_opts 2014-12-10 10:31:21 +01:00
vvfat.c block: update string sizes for filename,backing_file,exact_filename 2015-01-23 18:17:06 +01:00
win32-aio.c block: Rename BlockDriverCompletionFunc to BlockCompletionFunc 2014-10-20 13:41:27 +02:00
write-threshold.c block: add event when disk usage exceeds threshold 2015-02-06 17:24:21 +01:00