When invalidating a translation block, set an invalid flag into the
TranslationBlock structure first. It is also necessary to check whether
the target TB is still valid after acquiring 'tb_lock' but before calling
tb_add_jump() since TB lookup is to be performed out of 'tb_lock' in
future. Note that we don't have to check 'last_tb'; an already invalidated
TB will not be executed anyway and it is thus safe to patch it.
Suggested-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ensure atomicity and ordering of CPU's 'tb_flushed' access for future
translation block lookup out of 'tb_lock'.
This field can only be touched from another thread by tb_flush() in user
mode emulation. So the only access to be sequential atomic is:
* a single write in tb_flush();
* reads/writes out of 'tb_lock'.
In future, before enabling MTTCG in system mode, tb_flush() must be safe
and this field becomes unnecessary.
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20160715175852.30749-5-sergey.fedorov@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is a small clean up. tb_find_fast() is a final consumer of this
variable so no need to pass it by reference. 'last_tb' is always updated
by subsequent cpu_loop_exec_tb() in cpu_exec().
This change also simplifies calling cpu_exec_nocache() in
cpu_handle_exception().
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Message-Id: <20160715175852.30749-3-sergey.fedorov@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
instead of accessing tqe_prev field dircetly outside
of queue.h use macros to check if element is in list
and make sure that afer element is removed from list
tqe_prev field could be used to do the same check.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1469450832-84343-1-git-send-email-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
slave:~/.xie/qemu-colo # gcc --version
gcc (SUSE Linux) 4.3.4 [gcc-4_3-branch revision 152973]
slave:~/.xie/qemu-colo # make -j8
CC hw/net/e1000e_core.o
hw/net/e1000e_core.c:56: warning: ‘e1000e_set_interrupt_cause’ declared inline after being called
hw/net/e1000e_core.c:56: warning: previous declaration of ‘e1000e_set_interrupt_cause’ was here
LINK x86_64-softmmu/qemu-system-x86_64
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Reviewed-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
val is assigned twice; the second one should be combined with "|".
Reported by Coverity.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Commit 67a1de0d created a generated version file, and, in some
circumstances, also a temporary file. Make sure 'git add .'
won't check them into the repository.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Display the slot number of mhp_pc_dimm_assigned_slot()
using "%d" without the "0x".
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Display an exception number, generally defined as an hexadecimal
number (for instance, EXCP_HLT is 0x10001).
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
There is no need to make sure that the memory is zeroed after the
allocation if we also immediatly fill the whole buffer afterwards
with memcpy(). Thus g_new0 should be g_new instead. But since we
are also doing a memcpy() here, we can also simply replace both
with g_memdup() instead.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Acked-By: Artyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
tpm_cleanup is called from main() and also registered with atexit from
tpm_init. The function only visits the tpm_backends linked list, and the
atexit registration happens right after tpm_init fills in the list from
-tpmdev options. Therefore, the direct call is unnecessary. Remove it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Commit 0bab0ebb17 was supposed to fix
a mistake in the description of the leaky bucket algorithm, but the
version that finally landed after the review process was incorrect.
This patch solves that problem and hopefully clarifies the description
a bit better.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
QEMU's code relies on left shifts of signed integers always
being defined behaviour with the obvious 2s-complement
semantics. The only way to tell the compiler (and any
associated undefined-behaviour sanitizer) that we require a
C dialect with these semantics is to use the -fwrapv option.
This is a bit of a heavy hammer for the job as it also gives
us guaranteed semantics on integer arithmetic overflow which
in theory we don't require.
In an ideal world this would allow us to drop the warning
flag -Wno-shift-negative-value, but we must retain this to
avoid spurious warnings on clang versions predating the
fix to https://llvm.org/bugs/show_bug.cgi?id=25552.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1473685808-9629-1-git-send-email-peter.maydell@linaro.org
Right after main_loop ends, we release various things but keep iothread
alive. The latter is not prepared to the sudden change of resources.
Specifically, after bdrv_close_all(), virtio-scsi dataplane get a
surprise at the empty BlockBackend:
(gdb) bt
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:543
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:577
It is because the d->conf.blk->root is set to NULL, then
blk_get_aio_context() returns qemu_aio_context, whereas s->ctx is still
pointing to the iothread:
hw/scsi/virtio-scsi.c:543:
if (s->dataplane_started) {
assert(blk_get_aio_context(d->conf.blk) == s->ctx);
}
To fix this, let's stop iothreads before doing bdrv_close_all().
Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1473326931-9699-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
vq->avail.idx and vq->avail->ring[] are a 16bit values,
so read and write them with readw()/writew() instead of
readl()/writel().
To read/write a 16bit value with a 32bit accessor works fine
on little-endian CPU but not on big endian CPU.
[An equivalent patch for the writew() calls was also sent by
Zhang Shuai <zhangshuai13@huawei.com>.
--Stefan]
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-id: 1472330054-22607-1-git-send-email-lvivier@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Normal backup(sync='none') workflow:
step 1. NBD peformance I/O write from client to server
qcow2_co_writev
bdrv_co_writev
...
bdrv_aligned_pwritev
notifier_with_return_list_notify -> backup_do_cow
bdrv_driver_pwritev // write new contents
step 2. drive-backup sync=none
backup_do_cow
{
wait_for_overlapping_requests
cow_request_begin
for(; start < end; start++) {
bdrv_co_readv_no_serialising //read old contents from Secondary disk
bdrv_co_writev // write old contents to hidden-disk
}
cow_request_end
}
step 3. Then roll back to "step 1" to write new contents to Secondary disk.
And for replication, we must make sure that we only read the old contents from
Secondary disk in order to keep contents consistent.
1) Replication workflow of Secondary
virtio-blk
^
-------> 1 NBD |
|| server 3 replication
|| ^ ^
|| | backing backing |
|| Secondary disk 6<-------- hidden-disk 5 <-------- active-disk 4
|| | ^
|| '-------------------------'
|| drive-backup sync=none 2
Hence, we need these interfaces to implement coarse-grained serialization between
COW of Secondary disk and the read operation of replication.
Example codes about how to use them:
*#include "block/block_backup.h"
static coroutine_fn int xxx_co_readv()
{
CowRequest req;
BlockJob *job = secondary_disk->bs->job;
if (job) {
backup_wait_for_overlapping_requests(job, start, end);
backup_cow_request_begin(&req, job, start, end);
ret = bdrv_co_readv();
backup_cow_request_end(&req);
goto out;
}
ret = bdrv_co_readv();
out:
return ret;
}
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Wang WeiWei <wangww.fnst@cn.fujitsu.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1469602913-20979-4-git-send-email-xiecl.fnst@cn.fujitsu.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
In order to reduce completion latency it makes sense to harvest completed
requests ASAP. Very fast backend device can complete requests just after
submission, so it is worth trying to check ring buffer in order to peek
completed requests directly after io_submit() has been called.
Indeed, this patch reduces the completions latencies and increases the
overall throughput, e.g. the following is the percentiles of number of
completed requests at once:
1th 10th 20th 30th 40th 50th 60th 70th 80th 90th 99.99th
Before 2 4 42 112 128 128 128 128 128 128 128
After 1 1 4 14 33 45 47 48 50 51 108
That means, that before the current patch is applied the ring buffer is
observed as full (128 requests were consumed at once) in 60% of calls.
After patch is applied the distribution of number of completed requests
is "smoother" and the queue (requests in-flight) is almost never full.
The fio read results are the following (write results are almost the
same and are not showed here):
Before
------
job: (groupid=0, jobs=8): err= 0: pid=2227: Tue Jul 19 11:29:50 2016
Description : [Emulation of Storage Server Access Pattern]
read : io=54681MB, bw=1822.7MB/s, iops=179779, runt= 30001msec
slat (usec): min=172, max=16883, avg=338.35, stdev=109.66
clat (usec): min=1, max=21977, avg=1051.45, stdev=299.29
lat (usec): min=317, max=22521, avg=1389.83, stdev=300.73
clat percentiles (usec):
| 1.00th=[ 346], 5.00th=[ 596], 10.00th=[ 708], 20.00th=[ 852],
| 30.00th=[ 932], 40.00th=[ 996], 50.00th=[ 1048], 60.00th=[ 1112],
| 70.00th=[ 1176], 80.00th=[ 1256], 90.00th=[ 1384], 95.00th=[ 1496],
| 99.00th=[ 1800], 99.50th=[ 1928], 99.90th=[ 2320], 99.95th=[ 2672],
| 99.99th=[ 4704]
bw (KB /s): min=205229, max=553181, per=12.50%, avg=233278.26, stdev=18383.51
After
------
job: (groupid=0, jobs=8): err= 0: pid=2220: Tue Jul 19 11:31:51 2016
Description : [Emulation of Storage Server Access Pattern]
read : io=57637MB, bw=1921.2MB/s, iops=189529, runt= 30002msec
slat (usec): min=169, max=20636, avg=329.61, stdev=124.18
clat (usec): min=2, max=19592, avg=988.78, stdev=251.04
lat (usec): min=381, max=21067, avg=1318.42, stdev=243.58
clat percentiles (usec):
| 1.00th=[ 310], 5.00th=[ 580], 10.00th=[ 748], 20.00th=[ 876],
| 30.00th=[ 908], 40.00th=[ 948], 50.00th=[ 1012], 60.00th=[ 1064],
| 70.00th=[ 1080], 80.00th=[ 1128], 90.00th=[ 1224], 95.00th=[ 1288],
| 99.00th=[ 1496], 99.50th=[ 1608], 99.90th=[ 1960], 99.95th=[ 2256],
| 99.99th=[ 5408]
bw (KB /s): min=212149, max=390160, per=12.49%, avg=245746.04, stdev=11606.75
Throughput increased from 1822MB/s to 1921MB/s, average completion latencies
decreased from 1051us to 988us.
Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Message-id: 1468931263-32667-4-git-send-email-roman.penyaev@profitbricks.com
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Section "7.1.4 Use of library functions" in the C99 standard says:
If an argument to a function has an invalid value (such as [...]
a null pointer [...]) [...] the behavior is undefined.
Additionally the "searching and sorting" functions are specified as
requiring valid pointer values as described in 7.1.4.
This patch fixes the following sanitizer errors:
block/qcow2.c:1807:41: runtime error: null pointer passed as argument 2, which is declared to never be null
block/qcow2-cluster.c:86:26: runtime error: null pointer passed as argument 2, which is declared to never be null
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1473758138-19260-1-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Alex Bennée