qemu-e2k/block
Alberto Garcia b3cf1c7cf8 qcow2: Allow reading both COW regions with only one request
Reading both COW regions requires two separate requests, but it's
perfectly possible to merge them and perform only one. This generally
improves performance, particularly on rotating disk drives. The
downside is that the data in the middle region is read but discarded.

This patch takes a conservative approach and only merges reads when
the size of the middle region is <= 16KB.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-06-26 14:51:13 +02:00
..
accounting.c block: make accounting thread-safe 2017-06-16 07:55:00 +08:00
backup.c blockjob: introduce block_job_early_fail 2017-05-24 16:38:51 -04:00
blkdebug.c qapi: merge QInt and QFloat in QNum 2017-06-20 14:31:31 +02:00
blkreplay.c block: Do not unref bs->file on error in BD's open 2017-04-27 16:12:13 +02:00
blkverify.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
block-backend.c block: split BlockAcctStats creation and setup 2017-06-16 07:55:00 +08:00
bochs.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
cloop.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
commit.c commit: Fix completion with extra reference 2017-06-26 14:51:12 +02:00
crypto.c crypto: move 'opaque' parameter to (nearly) the end of parameter list 2017-05-09 14:41:47 +01:00
curl.c curl: do not do aio_poll when waiting for a free CURLState 2017-05-16 10:34:50 -04:00
dirty-bitmap.c block: protect modification of dirty bitmaps with a mutex 2017-06-16 07:55:00 +08:00
dmg-bz2.c dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
dmg.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
dmg.h dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
file-posix.c block/file-*: *_parse_filename() and colons 2017-05-29 15:39:54 +02:00
file-win32.c block/file-*: *_parse_filename() and colons 2017-05-29 15:39:54 +02:00
gluster.c block/gluster.c: Handle qdict_array_entries() failure 2017-06-09 08:41:29 -04:00
io.c block: use BDRV_POLL_WHILE() in bdrv_rw_vmstate() 2017-06-26 14:51:13 +02:00
iscsi-opts.c block/iscsi: statically link qemu_iscsi_opts 2017-01-27 18:07:58 +01:00
iscsi.c block/iscsi: enable filename option and parsing 2017-06-14 17:39:46 -04:00
linux-aio.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
Makefile.objs block/vxhs.c: Add support for a new block device type called "vxhs" 2017-04-24 15:08:42 -04:00
mirror.c block: protect modification of dirty bitmaps with a mutex 2017-06-16 07:55:00 +08:00
nbd-client.c nbd: rename read_sync and friends 2017-06-15 11:04:06 +02:00
nbd-client.h nbd: drop unused NBDClientSession.is_unix field 2017-03-27 14:41:01 +02:00
nbd.c qapi: merge QInt and QFloat in QNum 2017-06-20 14:31:31 +02:00
nfs.c QAPI patches for 2017-06-09 2017-06-22 11:34:39 +01:00
null.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
parallels.c block: Add errp to b{lk,drv}_truncate() 2017-04-28 16:02:02 +02:00
qapi.c QAPI patches for 2017-06-09 2017-06-22 11:34:39 +01:00
qcow2-cache.c qcow2: Remove stale comment 2016-11-25 13:51:30 +01:00
qcow2-cluster.c qcow2: Allow reading both COW regions with only one request 2017-06-26 14:51:13 +02:00
qcow2-refcount.c qcow2: Make distinction between zero cluster types obvious 2017-05-11 14:28:07 +02:00
qcow2-snapshot.c qcow2: Discard/zero clusters by byte count 2017-05-11 14:28:07 +02:00
qcow2.c qcow2: remove extra local_error variable 2017-05-29 15:39:53 +02:00
qcow2.h qcow2: Use unsigned int for both members of Qcow2COWRegion 2017-06-26 14:51:13 +02:00
qcow.c block/qcow.c: Fix memory leak in qcow_create() 2017-06-09 13:46:20 +02:00
qed-check.c
qed-cluster.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
qed-gencb.c
qed-l2-cache.c
qed-table.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
qed.c migration: migration.h was not needed 2017-05-18 19:20:59 +02:00
qed.h block: explicitly acquire aiocontext in timers that need it 2017-02-21 11:14:08 +00:00
quorum.c qapi: merge QInt and QFloat in QNum 2017-06-20 14:31:31 +02:00
raw-format.c block: Add .bdrv_truncate() error messages 2017-04-28 16:02:03 +02:00
rbd.c block/rbd: enable filename option and parsing 2017-06-14 17:39:46 -04:00
replication.c block: Make 'replication_state' an enum 2017-05-07 09:57:51 +03:00
sheepdog.c QAPI patches for 2017-06-09 2017-06-22 11:34:39 +01:00
snapshot.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
ssh.c qapi: merge QInt and QFloat in QNum 2017-06-20 14:31:31 +02:00
stream.c stream: fix crash in stream_start() when block_job_create() fails 2017-05-26 16:48:21 +02:00
throttle-groups.c throttle: Update throttle-groups.c documentation 2017-06-26 14:51:13 +02:00
trace-events block/vxhs.c: Add support for a new block device type called "vxhs" 2017-04-24 15:08:42 -04:00
vdi.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vhdx-endian.c
vhdx-log.c block: Add errp to b{lk,drv}_truncate() 2017-04-28 16:02:02 +02:00
vhdx.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vhdx.h
vmdk.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vpc.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vvfat.c qapi: merge QInt and QFloat in QNum 2017-06-20 14:31:31 +02:00
vxhs.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
win32-aio.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
write-threshold.c block: use bdrv_add_before_write_notifier 2016-10-07 13:34:07 +02:00