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QEMU With E2K User Support
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b94a261057
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Kevin Wolf b94a261057 block: Avoid unecessary drv->bdrv_getlength() calls 
The block layer generally keeps the size of an image cached in
bs->total_sectors so that it doesn't have to perform expensive
operations to get the size whenever it needs it.

This doesn't work however when using a backend that can change its size
without qemu being aware of it, i.e. passthrough of removable media like
CD-ROMs or floppy disks. For this reason, the caching is disabled when a
removable device is used.

It is obvious that checking whether the _guest_ device has removable
media isn't the right thing to do when we want to know whether the size
of the host backend can change. To make things worse, non-top-level
BlockDriverStates never have any device attached, which makes qemu
assume they are removable, so drv->bdrv_getlength() is always called on
the protocol layer. In the case of raw-posix, this causes unnecessary
lseek() system calls, which turned out to be rather expensive.

This patch completely changes the logic and disables bs->total_sectors
caching only for certain block driver types, for which a size change is
expected: host_cdrom and host_floppy on POSIX, host_device on win32; also
the raw format in case it sits on top of one of these protocols, but in
the common case the nested bdrv_getlength() call on the protocol driver
will use the cache again and avoid an expensive drv->bdrv_getlength()
call.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2013-10-29 13:10:26 +01:00
audio audio: remove CONFIG_MIXEMU configure option 2013-09-24 10:29:34 +02:00
backends
block block: Avoid unecessary drv->bdrv_getlength() calls 2013-10-29 13:10:26 +01:00
bsd-user *-user: Improve documentation for lock_user function 2013-09-20 20:09:24 +04:00
default-configs default-configs/: CONFIG_GDBSTUB_XML removed 2013-10-16 18:21:01 +02:00
disas disas/ppc.c: Fix little endian disassembly 2013-09-02 10:06:41 +02:00
docs qapi: fix documentation example 2013-10-21 16:49:35 +02:00
dtc@bc895d6d09
fpu
fsdev
gdb-xml target-arm: Add AArch64 gdbstub support 2013-09-10 19:11:28 +01:00
hw ahci: fix win7 hang on boot 2013-10-29 13:06:39 +01:00
include block: Avoid unecessary drv->bdrv_getlength() calls 2013-10-29 13:10:26 +01:00
libcacard Merge remote-tracking branch 'stefanha/block' into staging 2013-09-23 11:53:05 -05:00
linux-headers linux-headers: update to 3.12-rc1 2013-09-20 12:38:48 +02:00
linux-user cpu: Drop cpu_model_str from CPU_COMMON 2013-10-07 11:48:47 +02:00
net net: call socket_set_fast_reuse instead of setting SO_REUSEADDR 2013-10-02 19:20:31 +02:00
pc-bios Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
pixman@97336fad32
po
qapi qemu-ga: Extend 'guest-info' command to expose flag 'success-response' 2013-10-10 14:52:37 -05:00
qga qemu-ga: Extend 'guest-info' command to expose flag 'success-response' 2013-10-10 14:52:37 -05:00
qobject qdict: Extract qdict_extract_subqdict 2013-09-25 16:21:28 +02:00
qom cpu: Move cpu state syncs up into cpu_dump_state() 2013-09-20 12:37:52 +02:00
roms Update OpenBIOS images 2013-10-03 00:04:20 +01:00
scripts Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
slirp slirp: call socket_set_fast_reuse instead of setting SO_REUSEADDR 2013-10-02 19:20:31 +02:00
stubs Merge remote-tracking branch 'kiszka/queues/slirp' into staging 2013-09-17 10:01:24 -05:00
sysconfigs/target
target-alpha target-alpha: Convert to new ldst opcodes 2013-10-12 16:19:20 -07:00
target-arm Merge remote-tracking branch 'bonzini/configure' into staging 2013-10-18 10:01:37 -07:00
target-cris tcg: Remove stray semi-colons from target-*/helper.h 2013-10-10 11:43:37 -07:00
target-i386 Merge remote-tracking branch 'qemu-kvm/uq/master' into staging 2013-10-18 10:03:24 -07:00
target-lm32 target: Include softmmu_exec.h where forgotten 2013-09-02 09:08:30 -07:00
target-m68k Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
target-microblaze tcg: Move helper registration into tcg_context_init 2013-10-10 11:43:37 -07:00
target-mips Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
target-moxie cpu: Drop cpu_model_str from CPU_COMMON 2013-10-07 11:48:47 +02:00
target-openrisc Merge remote-tracking branch 'jliu/or32' into staging 2013-10-14 09:15:47 -07:00
target-ppc Merge remote-tracking branch 'bonzini/configure' into staging 2013-10-18 10:01:37 -07:00
target-s390x exec: Fix prototype of phys_mem_set_alloc and related functions 2013-10-14 08:50:34 -07:00
target-sh4 Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
target-sparc Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
target-unicore32 Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
target-xtensa target-xtensa: add in_asm logging 2013-10-15 17:23:46 +04:00
tcg tcg-ppc64: Support new ldst opcodes 2013-10-12 16:19:20 -07:00
tests tests: Multiboot mmap test case 2013-10-28 17:34:42 +01:00
trace
ui Merge remote-tracking branch 'bonzini/configure' into staging 2013-10-18 10:01:37 -07:00
util qemu-thread: add QemuEvent 2013-10-17 17:30:55 +02:00
.exrc
.gitignore qemu-ga: Add configure options to specify path to Windows/VSS SDK 2013-09-09 14:17:56 -05:00
.gitmodules Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
.mailmap Update mailmap 2013-09-05 09:40:31 -05:00
aio-posix.c
aio-win32.c
arch_init.c pc,pci,virtio fixes and cleanups 2013-09-30 17:15:01 -05:00
async.c
balloon.c
block-migration.c migration: omit drive ref as we have bdrv_ref now 2013-09-06 15:25:08 +02:00
block.c block: Avoid unecessary drv->bdrv_getlength() calls 2013-10-29 13:10:26 +01:00
blockdev-nbd.c nbd: use BlockDriverState refcnt 2013-09-06 15:25:08 +02:00
blockdev.c blockdev: fix cdrom read_only flag 2013-10-17 10:19:59 +02:00
blockjob.c qapi: make use of new BlockJobType 2013-10-11 10:52:54 +02:00
bt-host.c
bt-vhci.c
Changelog Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
CODING_STYLE
configure configure: Remove CONFIG_QEMU_LDST_OPTIMIZATION 2013-10-10 11:44:26 -07:00
COPYING
COPYING.LIB
coroutine-gthread.c
coroutine-sigaltstack.c
coroutine-ucontext.c
coroutine-win32.c
cpu-exec.c cpu-exec: Also reload CPUClass *cc after longjmp return in cpu_exec() 2013-10-07 11:46:58 +02:00
cpus.c icount: make it thread-safe 2013-10-17 17:31:00 +02:00
cputlb.c cputlb: Remove dead function tlb_update_dirty() 2013-10-07 11:48:03 +02:00
device_tree.c
device-hotplug.c
disas.c
dma-helpers.c
dump.c cpu: Use QTAILQ for CPU list 2013-09-03 12:25:55 +02:00
exec.c exec: Fix bounce buffer allocation in address_space_map() 2013-10-28 17:34:42 +01:00
gdbstub.c gdbstub: call socket_set_fast_reuse instead of setting SO_REUSEADDR 2013-10-02 19:20:31 +02:00
HACKING
hmp-commands.hx hmp: add interface hmp_snapshot_delete_blkdev_internal 2013-09-12 10:12:47 +02:00
hmp.c hmp: drop bogus "[not inserted]" 2013-10-17 10:10:14 +02:00
hmp.h hmp: add interface hmp_snapshot_delete_blkdev_internal 2013-09-12 10:12:47 +02:00
iohandler.c
ioport.c portio: Allow to mark portio lists as coalesced MMIO flushing 2013-10-17 17:24:15 +02:00
kvm-all.c Merge remote-tracking branch 'qemu-kvm/uq/master' into staging 2013-09-23 11:52:49 -05:00
kvm-stub.c kvm irqfd: support direct msimessage to irq translation 2013-09-20 12:37:52 +02:00
LICENSE
main-loop.c slirp: set mainloop timeout with more precise value 2013-09-17 12:26:05 +02:00
MAINTAINERS Merge remote-tracking branch 'rth/tcg-pull' into staging 2013-10-11 09:36:52 -07:00
Makefile build: add command check-clean 2013-10-11 16:50:01 +02:00
Makefile.objs qemu-ga: Add Windows VSS provider and requester as DLL 2013-09-09 14:17:57 -05:00
Makefile.target default-configs/: CONFIG_GDBSTUB_XML removed 2013-10-16 18:21:01 +02:00
memory_mapping.c cpu: Use QTAILQ for CPU list 2013-09-03 12:25:55 +02:00
memory.c memory: fix 128 arithmetic in info mtree 2013-10-17 17:24:14 +02:00
migration-exec.c
migration-fd.c
migration-rdma.c rdma: constify ram_chunk_{index, start, end} 2013-09-24 13:22:50 +02:00
migration-tcp.c
migration-unix.c
migration.c migration: Fix compiler warning ('caps' may be used uninitialized) 2013-10-05 14:02:29 +04:00
monitor.c QOM CPUState refactorings / X86CPU 2013-09-03 12:33:32 -05:00
nbd.c nbd: use BlockDriverState refcnt 2013-09-06 15:25:08 +02:00
os-posix.c
os-win32.c
page_cache.c
qapi-schema.json blockdev: 'blockdev-add' QMP command 2013-10-11 16:50:01 +02:00
qdev-monitor.c qdev-monitor: Group "device_add help" and "info qdm" by category 2013-10-11 09:36:29 -07:00
qdict-test-data.txt
qemu-bridge-helper.c
qemu-char.c Merge remote-tracking branch 'amit/char-remove-watch-on-unplug' into staging 2013-10-10 13:16:02 -07:00
qemu-coroutine-io.c
qemu-coroutine-lock.c
qemu-coroutine-sleep.c
qemu-coroutine.c coroutine: add ./configure --disable-coroutine-pool 2013-09-12 10:12:48 +02:00
qemu-doc.texi
qemu-img-cmds.hx block: Image file option amendment 2013-09-12 10:12:46 +02:00
qemu-img.c qemu-img: add special exit code if bdrv_check is not supported 2013-10-24 12:03:18 +02:00
qemu-img.texi block: Image file option amendment 2013-09-12 10:12:46 +02:00
qemu-io-cmds.c block/qapi: Human-readable ImageInfoSpecific dump 2013-10-11 10:52:54 +02:00
qemu-io.c qemu-io: Let "open" pass options to block driver 2013-10-11 16:50:02 +02:00
qemu-log.c
qemu-nbd.c block: Error parameter for open functions 2013-09-12 10:12:48 +02:00
qemu-nbd.texi
qemu-options-wrapper.h
qemu-options.h
qemu-options.hx block: Add iops_size to do the iops accounting for a given io size. 2013-09-06 15:25:07 +02:00
qemu-seccomp.c seccomp: fine tuning whitelist by adding times() 2013-09-24 15:15:16 -03:00
qemu-tech.texi
qemu-timer.c timer: add timer_mod_anticipate and timer_mod_anticipate_ns 2013-10-17 17:31:00 +02:00
qemu.nsi Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
qemu.sasl
qmp-commands.hx blockdev: 'blockdev-add' QMP command 2013-10-11 16:50:01 +02:00
qmp.c
qtest.c qtest: Fix FMT_timeval vs time_t 2013-09-02 09:08:29 -07:00
readline.c monitor: avoid use of global *cur_mon in readline_completion() 2013-08-30 07:41:14 -04:00
README Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
rules.mak rules.mak: New string testing functions 2013-10-16 18:21:00 +02:00
savevm.c savevm: fix wrong initialization by ram_control_load_hook 2013-09-24 13:22:08 +02:00
spice-qemu-char.c
tcg-runtime.c
tci.c misc: Use new rotate functions 2013-09-25 21:23:05 +02:00
thread-pool.c
thunk.c
tpm.c
trace-events Merge remote-tracking branch 'mjt/trivial-patches' into staging 2013-09-23 11:52:55 -05:00
translate-all.c exec: Delete is_tcg_gen_code and GETRA_EXT 2013-10-10 11:44:25 -07:00
translate-all.h
user-exec.c
VERSION
version.rc Use qemu-project.org domain name 2013-10-11 09:34:56 -07:00
vl.c spice: fix multihead support 2013-10-17 12:42:54 +02:00
xbzrle.c
xen-all.c qemu/xen: make use of xenstore relative paths 2013-10-10 14:25:52 +00:00
xen-mapcache.c
xen-stub.c pc: Initializing ram_memory under Xen. 2013-09-09 16:22:19 +00:00

README 

Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org

- QEMU team