5:17 a.m.
I propose to merge only the first two patches. The third one is just an
alternative to the first two, but honestly, I view it as a terrible
hack. Nevertheless, a hack worth discussion.
Michal Prívozník (3):
virthreadpool: Allow setting identity for workers
qemu: Set "qemu-event" thread identity
*** DO NOT MERGE ***
src/nwfilter/nwfilter_dhcpsnoop.c | 1 +
src/qemu/qemu_driver.c | 5 ++++-
src/qemu/qemu_process.c | 4 ++++
src/rpc/virnetserver.c | 1 +
src/util/virthreadpool.c | 12 ++++++++++++
src/util/virthreadpool.h | 12 +++++++-----
6 files changed, 29 insertions(+), 6 deletions(-)
--
2.32.0
5:17 a.m.
New subject: [PATCH 1/3] virthreadpool: Allow setting identity for workers
In some cases the worker func running inside the pool may rely on
virIdentity. While worker func could check for identity and set
one it is not optimal - it may not have access to the identity of
the thread creating the pool and thus would have to call
virIdentityGetSystem(). Allow passing identity when creating the
pool.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/nwfilter/nwfilter_dhcpsnoop.c | 1 +
src/qemu/qemu_driver.c | 4 +++-
src/rpc/virnetserver.c | 1 +
src/util/virthreadpool.c | 12 ++++++++++++
src/util/virthreadpool.h | 12 +++++++-----
5 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/src/nwfilter/nwfilter_dhcpsnoop.c b/src/nwfilter/nwfilter_dhcpsnoop.c
index 4b62a7b661..b0297f0741 100644
--- a/src/nwfilter/nwfilter_dhcpsnoop.c
+++ b/src/nwfilter/nwfilter_dhcpsnoop.c
@@ -1333,6 +1333,7 @@ virNWFilterDHCPSnoopThread(void *req0)
worker = virThreadPoolNewFull(1, 1, 0,
virNWFilterDHCPDecodeWorker,
"dhcp-decode",
+ NULL,
req);
}
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 6997dc7dea..a8bf0ecc6f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -914,7 +914,9 @@ qemuStateInitialize(bool privileged,
* running domains since there might occur some QEMU monitor
* events that will be dispatched to the worker pool */
qemu_driver->workerPool = virThreadPoolNewFull(0, 1, 0, qemuProcessEventHandler,
- "qemu-event", qemu_driver);
+ "qemu-event",
+ NULL,
+ qemu_driver);
if (!qemu_driver->workerPool)
goto error;
diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
index dc8f32b095..c7b4939398 100644
--- a/src/rpc/virnetserver.c
+++ b/src/rpc/virnetserver.c
@@ -378,6 +378,7 @@ virNetServer *virNetServerNew(const char *name,
priority_workers,
virNetServerHandleJob,
"rpc-worker",
+ NULL,
srv)))
goto error;
diff --git a/src/util/virthreadpool.c b/src/util/virthreadpool.c
index 92b7cac286..7bf4333885 100644
--- a/src/util/virthreadpool.c
+++ b/src/util/virthreadpool.c
@@ -55,6 +55,8 @@ struct _virThreadPool {
virThreadPoolJobList jobList;
size_t jobQueueDepth;
+ virIdentity *identity;
+
virMutex mutex;
virCond cond;
virCond quit_cond;
@@ -99,6 +101,9 @@ static void virThreadPoolWorker(void *opaque)
virMutexLock(&pool->mutex);
+ if (pool->identity)
+ virIdentitySetCurrent(pool->identity);
+
while (1) {
/* In order to support async worker termination, we need ensure that
* both busy and free workers know if they need to terminated. Thus,
@@ -219,6 +224,7 @@ virThreadPoolNewFull(size_t minWorkers,
size_t prioWorkers,
virThreadPoolJobFunc func,
const char *name,
+ virIdentity *identity,
void *opaque)
{
virThreadPool *pool;
@@ -234,6 +240,9 @@ virThreadPoolNewFull(size_t minWorkers,
pool->jobName = name;
pool->jobOpaque = opaque;
+ if (identity)
+ pool->identity = g_object_ref(identity);
+
if (virMutexInit(&pool->mutex) < 0)
goto error;
if (virCondInit(&pool->cond) < 0)
@@ -300,6 +309,9 @@ void virThreadPoolFree(virThreadPool *pool)
virMutexLock(&pool->mutex);
virThreadPoolDrainLocked(pool);
+ if (pool->identity)
+ g_object_unref(pool->identity);
+
g_free(pool->workers);
virMutexUnlock(&pool->mutex);
virMutexDestroy(&pool->mutex);
diff --git a/src/util/virthreadpool.h b/src/util/virthreadpool.h
index 619d128e9a..c6b9f31916 100644
--- a/src/util/virthreadpool.h
+++ b/src/util/virthreadpool.h
@@ -22,17 +22,19 @@
#pragma once
#include "internal.h"
+#include "viridentity.h"
typedef struct _virThreadPool virThreadPool;
typedef void (*virThreadPoolJobFunc)(void *jobdata, void *opaque);
virThreadPool *virThreadPoolNewFull(size_t minWorkers,
- size_t maxWorkers,
- size_t prioWorkers,
- virThreadPoolJobFunc func,
- const char *name,
- void *opaque) ATTRIBUTE_NONNULL(4);
+ size_t maxWorkers,
+ size_t prioWorkers,
+ virThreadPoolJobFunc func,
+ const char *name,
+ virIdentity *identity,
+ void *opaque) ATTRIBUTE_NONNULL(4);
size_t virThreadPoolGetMinWorkers(virThreadPool *pool);
size_t virThreadPoolGetMaxWorkers(virThreadPool *pool);
--
2.32.0
9:39 a.m.
New subject: [PATCH 1/3] virthreadpool: Allow setting identity for workers
On Tue, Oct 26, 2021 at 12:17:06PM +0200, Michal Privoznik wrote:
In some cases the worker func running inside the pool may rely on
virIdentity. While worker func could check for identity and set
one it is not optimal - it may not have access to the identity of
the thread creating the pool and thus would have to call
virIdentityGetSystem(). Allow passing identity when creating the
pool.
I wonder if we should have an identity passed via virThreadPoolSendJob,
so whatever queues the job can preserve its identity ?
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/nwfilter/nwfilter_dhcpsnoop.c | 1 +
src/qemu/qemu_driver.c | 4 +++-
src/rpc/virnetserver.c | 1 +
src/util/virthreadpool.c | 12 ++++++++++++
src/util/virthreadpool.h | 12 +++++++-----
5 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/src/nwfilter/nwfilter_dhcpsnoop.c b/src/nwfilter/nwfilter_dhcpsnoop.c
index 4b62a7b661..b0297f0741 100644
--- a/src/nwfilter/nwfilter_dhcpsnoop.c
+++ b/src/nwfilter/nwfilter_dhcpsnoop.c
@@ -1333,6 +1333,7 @@ virNWFilterDHCPSnoopThread(void *req0)
worker = virThreadPoolNewFull(1, 1, 0,
virNWFilterDHCPDecodeWorker,
"dhcp-decode",
+ NULL,
req);
}
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 6997dc7dea..a8bf0ecc6f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -914,7 +914,9 @@ qemuStateInitialize(bool privileged,
* running domains since there might occur some QEMU monitor
* events that will be dispatched to the worker pool */
qemu_driver->workerPool = virThreadPoolNewFull(0, 1, 0, qemuProcessEventHandler,
- "qemu-event",
qemu_driver);
+ "qemu-event",
+ NULL,
+ qemu_driver);
if (!qemu_driver->workerPool)
goto error;
diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
index dc8f32b095..c7b4939398 100644
--- a/src/rpc/virnetserver.c
+++ b/src/rpc/virnetserver.c
@@ -378,6 +378,7 @@ virNetServer *virNetServerNew(const char *name,
priority_workers,
virNetServerHandleJob,
"rpc-worker",
+ NULL,
srv)))
goto error;
diff --git a/src/util/virthreadpool.c b/src/util/virthreadpool.c
index 92b7cac286..7bf4333885 100644
--- a/src/util/virthreadpool.c
+++ b/src/util/virthreadpool.c
@@ -55,6 +55,8 @@ struct _virThreadPool {
virThreadPoolJobList jobList;
size_t jobQueueDepth;
+ virIdentity *identity;
+
virMutex mutex;
virCond cond;
virCond quit_cond;
@@ -99,6 +101,9 @@ static void virThreadPoolWorker(void *opaque)
virMutexLock(&pool->mutex);
+ if (pool->identity)
+ virIdentitySetCurrent(pool->identity);
+
while (1) {
/* In order to support async worker termination, we need ensure that
* both busy and free workers know if they need to terminated. Thus,
@@ -219,6 +224,7 @@ virThreadPoolNewFull(size_t minWorkers,
size_t prioWorkers,
virThreadPoolJobFunc func,
const char *name,
+ virIdentity *identity,
void *opaque)
{
virThreadPool *pool;
@@ -234,6 +240,9 @@ virThreadPoolNewFull(size_t minWorkers,
pool->jobName = name;
pool->jobOpaque = opaque;
+ if (identity)
+ pool->identity = g_object_ref(identity);
+
if (virMutexInit(&pool->mutex) < 0)
goto error;
if (virCondInit(&pool->cond) < 0)
@@ -300,6 +309,9 @@ void virThreadPoolFree(virThreadPool *pool)
virMutexLock(&pool->mutex);
virThreadPoolDrainLocked(pool);
+ if (pool->identity)
+ g_object_unref(pool->identity);
+
g_free(pool->workers);
virMutexUnlock(&pool->mutex);
virMutexDestroy(&pool->mutex);
diff --git a/src/util/virthreadpool.h b/src/util/virthreadpool.h
index 619d128e9a..c6b9f31916 100644
--- a/src/util/virthreadpool.h
+++ b/src/util/virthreadpool.h
@@ -22,17 +22,19 @@
#pragma once
#include "internal.h"
+#include "viridentity.h"
typedef struct _virThreadPool virThreadPool;
typedef void (*virThreadPoolJobFunc)(void *jobdata, void *opaque);
virThreadPool *virThreadPoolNewFull(size_t minWorkers,
- size_t maxWorkers,
- size_t prioWorkers,
- virThreadPoolJobFunc func,
- const char *name,
- void *opaque) ATTRIBUTE_NONNULL(4);
+ size_t maxWorkers,
+ size_t prioWorkers,
+ virThreadPoolJobFunc func,
+ const char *name,
+ virIdentity *identity,
+ void *opaque) ATTRIBUTE_NONNULL(4);
size_t virThreadPoolGetMinWorkers(virThreadPool *pool);
size_t virThreadPoolGetMaxWorkers(virThreadPool *pool);
--
2.32.0
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
9:49 a.m.
New subject: [PATCH 1/3] virthreadpool: Allow setting identity for workers
On 10/26/21 4:39 PM, Daniel P. Berrangé wrote:
On Tue, Oct 26, 2021 at 12:17:06PM +0200, Michal Privoznik wrote:
> In some cases the worker func running inside the pool may rely on
> virIdentity. While worker func could check for identity and set
> one it is not optimal - it may not have access to the identity of
> the thread creating the pool and thus would have to call
> virIdentityGetSystem(). Allow passing identity when creating the
> pool.
I wonder if we should have an identity passed via virThreadPoolSendJob,
so whatever queues the job can preserve its identity ?
I thought about this too, but the threat that's doing that doesn't have
an identity set either:
#0 virThreadPoolSendJob (pool=0x7f2ff010a370, priority=0, jobData=0x7f2fdc0b1f10) at
../src/util/virthreadpool.c:390
#1 0x00007f30301f5240 in qemuProcessEventSubmit (driver=0x7f2ff0022370,
event=0x7f3012ffc880) at ../src/qemu/qemu_process.c:300
#2 0x00007f30301f8d13 in qemuProcessHandleSerialChanged (mon=0x7f2ff00295d0,
vm=0x7f2ff0037830, devAlias=0x7f2fdc12f9e0 "channel0", connected=false,
opaque=0x7f2ff0022370) at ../src/qemu/qemu_process.c:1540
#3 0x00007f30301c37f2 in qemuMonitorEmitSerialChange (mon=0x7f2ff00295d0,
devAlias=0x7f2fdc12f9e0 "channel0", connected=false) at
../src/qemu/qemu_monitor.c:1373
#4 0x00007f30301d48c8 in qemuMonitorJSONHandleSerialChange (mon=0x7f2ff00295d0,
data=0x7f2fdc0b2b40) at ../src/qemu/qemu_monitor_json.c:1145
#5 0x00007f30301d1725 in qemuMonitorJSONIOProcessEvent (mon=0x7f2ff00295d0,
obj=0x7f2fdc0b2770) at ../src/qemu/qemu_monitor_json.c:208
#6 0x00007f30301d1933 in qemuMonitorJSONIOProcessLine (mon=0x7f2ff00295d0,
line=0x7f2fdc0b4cd0 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}", msg=0x0) at ../src/qemu/qemu_monitor_json.c:236
#7 0x00007f30301d1bcc in qemuMonitorJSONIOProcess (mon=0x7f2ff00295d0,
data=0x7f2fdc12f590 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}\r\n", len=135, msg=0x0) at
../src/qemu/qemu_monitor_json.c:274
#8 0x00007f30301c0400 in qemuMonitorIOProcess (mon=0x7f2ff00295d0) at
../src/qemu/qemu_monitor.c:347
#9 0x00007f30301c0c80 in qemuMonitorIO (socket=0x7f2ff0017280, cond=0,
opaque=0x7f2ff00295d0) at ../src/qemu/qemu_monitor.c:573
#10 0x00007f3036ba8c77 in socket_source_dispatch () at /usr/lib64/libgio-2.0.so.0
#11 0x00007f3036d8b9d0 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#12 0x00007f3036d8bd78 in g_main_context_iterate.constprop () at
/usr/lib64/libglib-2.0.so.0
#13 0x00007f3036d8c06b in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
#14 0x00007f3036f81d7b in virEventThreadWorker (opaque=0x7f2ff00b10c0) at
../src/util/vireventthread.c:124
#15 0x00007f3036db52bd in g_thread_proxy () at /usr/lib64/libglib-2.0.so.0
#16 0x00007f3036235e3e in start_thread () at /lib64/libpthread.so.0
#17 0x00007f30369ffd6f in clone () at /lib64/libc.so.6
virThreadPoolSendJob 19 $ call virIdentityGetCurrent()
$1 = 0x0
Michal
10:06 a.m.
New subject: [PATCH 1/3] virthreadpool: Allow setting identity for workers
On Tue, Oct 26, 2021 at 04:49:55PM +0200, Michal Prívozník wrote:
On 10/26/21 4:39 PM, Daniel P. Berrangé wrote:
> On Tue, Oct 26, 2021 at 12:17:06PM +0200, Michal Privoznik wrote:
>> In some cases the worker func running inside the pool may rely on
>> virIdentity. While worker func could check for identity and set
>> one it is not optimal - it may not have access to the identity of
>> the thread creating the pool and thus would have to call
>> virIdentityGetSystem(). Allow passing identity when creating the
>> pool.
>
> I wonder if we should have an identity passed via virThreadPoolSendJob,
> so whatever queues the job can preserve its identity ?
I thought about this too, but the threat that's doing that doesn't have
an identity set either:
#0 virThreadPoolSendJob (pool=0x7f2ff010a370, priority=0, jobData=0x7f2fdc0b1f10) at
../src/util/virthreadpool.c:390
#1 0x00007f30301f5240 in qemuProcessEventSubmit (driver=0x7f2ff0022370,
event=0x7f3012ffc880) at ../src/qemu/qemu_process.c:300
#2 0x00007f30301f8d13 in qemuProcessHandleSerialChanged (mon=0x7f2ff00295d0,
vm=0x7f2ff0037830, devAlias=0x7f2fdc12f9e0 "channel0", connected=false,
opaque=0x7f2ff0022370) at ../src/qemu/qemu_process.c:1540
#3 0x00007f30301c37f2 in qemuMonitorEmitSerialChange (mon=0x7f2ff00295d0,
devAlias=0x7f2fdc12f9e0 "channel0", connected=false) at
../src/qemu/qemu_monitor.c:1373
#4 0x00007f30301d48c8 in qemuMonitorJSONHandleSerialChange (mon=0x7f2ff00295d0,
data=0x7f2fdc0b2b40) at ../src/qemu/qemu_monitor_json.c:1145
#5 0x00007f30301d1725 in qemuMonitorJSONIOProcessEvent (mon=0x7f2ff00295d0,
obj=0x7f2fdc0b2770) at ../src/qemu/qemu_monitor_json.c:208
#6 0x00007f30301d1933 in qemuMonitorJSONIOProcessLine (mon=0x7f2ff00295d0,
line=0x7f2fdc0b4cd0 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}", msg=0x0) at ../src/qemu/qemu_monitor_json.c:236
#7 0x00007f30301d1bcc in qemuMonitorJSONIOProcess (mon=0x7f2ff00295d0,
data=0x7f2fdc12f590 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}\r\n", len=135, msg=0x0) at
../src/qemu/qemu_monitor_json.c:274
#8 0x00007f30301c0400 in qemuMonitorIOProcess (mon=0x7f2ff00295d0) at
../src/qemu/qemu_monitor.c:347
#9 0x00007f30301c0c80 in qemuMonitorIO (socket=0x7f2ff0017280, cond=0,
opaque=0x7f2ff00295d0) at ../src/qemu/qemu_monitor.c:573
#10 0x00007f3036ba8c77 in socket_source_dispatch () at /usr/lib64/libgio-2.0.so.0
#11 0x00007f3036d8b9d0 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#12 0x00007f3036d8bd78 in g_main_context_iterate.constprop () at
/usr/lib64/libglib-2.0.so.0
#13 0x00007f3036d8c06b in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
#14 0x00007f3036f81d7b in virEventThreadWorker (opaque=0x7f2ff00b10c0) at
../src/util/vireventthread.c:124
#15 0x00007f3036db52bd in g_thread_proxy () at /usr/lib64/libglib-2.0.so.0
#16 0x00007f3036235e3e in start_thread () at /lib64/libpthread.so.0
#17 0x00007f30369ffd6f in clone () at /lib64/libc.so.6
virThreadPoolSendJob 19 $ call virIdentityGetCurrent()
$1 = 0x0
Hmm, yes, because that's from the event loop thread.
This actually makes me wonder if we actually need the worker pool at all
here. The worker pool is global to the driver, so events for all VMs are
being processed in the pool and so will contend for resource.
This made sense when all monitor I/O was procssed by the main event
loop thread, but now we have a per-VM event loop thread. Seems like
we could just process events directly in the per-VM thread potentially,
unless something they do synchronously needs to do more monitor I/O
None the less, that's too big of a change todo in a hurry, so lets
go with your patches here.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
10:14 a.m.
New subject: [PATCH 1/3] virthreadpool: Allow setting identity for workers
On 10/26/21 5:06 PM, Daniel P. Berrangé wrote:
On Tue, Oct 26, 2021 at 04:49:55PM +0200, Michal Prívozník wrote:
> On 10/26/21 4:39 PM, Daniel P. Berrangé wrote:
>> On Tue, Oct 26, 2021 at 12:17:06PM +0200, Michal Privoznik wrote:
>>> In some cases the worker func running inside the pool may rely on
>>> virIdentity. While worker func could check for identity and set
>>> one it is not optimal - it may not have access to the identity of
>>> the thread creating the pool and thus would have to call
>>> virIdentityGetSystem(). Allow passing identity when creating the
>>> pool.
>>
>> I wonder if we should have an identity passed via virThreadPoolSendJob,
>> so whatever queues the job can preserve its identity ?
>
> I thought about this too, but the threat that's doing that doesn't have
> an identity set either:
>
> #0 virThreadPoolSendJob (pool=0x7f2ff010a370, priority=0, jobData=0x7f2fdc0b1f10) at
../src/util/virthreadpool.c:390
> #1 0x00007f30301f5240 in qemuProcessEventSubmit (driver=0x7f2ff0022370,
event=0x7f3012ffc880) at ../src/qemu/qemu_process.c:300
> #2 0x00007f30301f8d13 in qemuProcessHandleSerialChanged (mon=0x7f2ff00295d0,
vm=0x7f2ff0037830, devAlias=0x7f2fdc12f9e0 "channel0", connected=false,
opaque=0x7f2ff0022370) at ../src/qemu/qemu_process.c:1540
> #3 0x00007f30301c37f2 in qemuMonitorEmitSerialChange (mon=0x7f2ff00295d0,
devAlias=0x7f2fdc12f9e0 "channel0", connected=false) at
../src/qemu/qemu_monitor.c:1373
> #4 0x00007f30301d48c8 in qemuMonitorJSONHandleSerialChange (mon=0x7f2ff00295d0,
data=0x7f2fdc0b2b40) at ../src/qemu/qemu_monitor_json.c:1145
> #5 0x00007f30301d1725 in qemuMonitorJSONIOProcessEvent (mon=0x7f2ff00295d0,
obj=0x7f2fdc0b2770) at ../src/qemu/qemu_monitor_json.c:208
> #6 0x00007f30301d1933 in qemuMonitorJSONIOProcessLine (mon=0x7f2ff00295d0,
line=0x7f2fdc0b4cd0 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}", msg=0x0) at ../src/qemu/qemu_monitor_json.c:236
> #7 0x00007f30301d1bcc in qemuMonitorJSONIOProcess (mon=0x7f2ff00295d0,
data=0x7f2fdc12f590 "{\"timestamp\": {\"seconds\": 1635259527,
\"microseconds\": 380958}, \"event\": \"VSERPORT_CHANGE\",
\"data\": {\"open\": false, \"id\":
\"channel0\"}}\r\n", len=135, msg=0x0) at
../src/qemu/qemu_monitor_json.c:274
> #8 0x00007f30301c0400 in qemuMonitorIOProcess (mon=0x7f2ff00295d0) at
../src/qemu/qemu_monitor.c:347
> #9 0x00007f30301c0c80 in qemuMonitorIO (socket=0x7f2ff0017280, cond=0,
opaque=0x7f2ff00295d0) at ../src/qemu/qemu_monitor.c:573
> #10 0x00007f3036ba8c77 in socket_source_dispatch () at /usr/lib64/libgio-2.0.so.0
> #11 0x00007f3036d8b9d0 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
> #12 0x00007f3036d8bd78 in g_main_context_iterate.constprop () at
/usr/lib64/libglib-2.0.so.0
> #13 0x00007f3036d8c06b in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
> #14 0x00007f3036f81d7b in virEventThreadWorker (opaque=0x7f2ff00b10c0) at
../src/util/vireventthread.c:124
> #15 0x00007f3036db52bd in g_thread_proxy () at /usr/lib64/libglib-2.0.so.0
> #16 0x00007f3036235e3e in start_thread () at /lib64/libpthread.so.0
> #17 0x00007f30369ffd6f in clone () at /lib64/libc.so.6
>
> virThreadPoolSendJob 19 $ call virIdentityGetCurrent()
> $1 = 0x0
Hmm, yes, because that's from the event loop thread.
This actually makes me wonder if we actually need the worker pool at all
here. The worker pool is global to the driver, so events for all VMs are
being processed in the pool and so will contend for resource.
This made sense when all monitor I/O was procssed by the main event
loop thread, but now we have a per-VM event loop thread. Seems like
we could just process events directly in the per-VM thread potentially,
unless something they do synchronously needs to do more monitor I/O
Some of them do. They do acquire modify job which may result in
deadlock. For instance, a thread acquires a job, proceeds to monitor and
as soon as it tries to send something an event is delivered. Let it be
an event that needs modify job. But such job can't be acquired really
because there's the thread that's trying to talk on monitor.
None the less, that's too big of a change todo in a hurry, so lets
go with your patches here.
Okay, pushed. Thanks.
Michal
5:17 a.m.
New subject: [PATCH 2/3] qemu: Set "qemu-event" thread identity
It may happen that qemuProcessStop() is called from "qemu-event"
thread. But this thread doesn't have any virIdentity set
(virIdentity being thread local) and therefore it may be unable
to open connection to secondary drivers. It is unable to do so
in split daemon scenario, because in there opening a connection
is coupled with copying current thread identity onto the
connection. Code-wise, virIdentityGetCurrent() returns NULL which
in turn makes virGetConnectGeneric() fail. This problem does not
occur in monolithic daemon scenario, because no identity copying
is done there.
Long story short, inability to open secondary driver connection
can lead to unwanted results. Therefore, do what
qemuProcessReconnectHelper() does - set the new thread identity
to be the one of the caller.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2013573
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/qemu/qemu_driver.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a8bf0ecc6f..70b5f37e6b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -571,6 +571,7 @@ qemuStateInitialize(bool privileged,
size_t i;
const char *defsecmodel = NULL;
g_autofree virSecurityManager **sec_managers = NULL;
+ g_autoptr(virIdentity) identity = virIdentityGetCurrent();
qemu_driver = g_new0(virQEMUDriver, 1);
@@ -915,7 +916,7 @@ qemuStateInitialize(bool privileged,
* events that will be dispatched to the worker pool */
qemu_driver->workerPool = virThreadPoolNewFull(0, 1, 0, qemuProcessEventHandler,
"qemu-event",
- NULL,
+ identity,
qemu_driver);
if (!qemu_driver->workerPool)
goto error;
--
2.32.0
9:31 a.m.
New subject: [PATCH 2/3] qemu: Set "qemu-event" thread identity
On Tue, Oct 26, 2021 at 12:17:07PM +0200, Michal Privoznik wrote:
It may happen that qemuProcessStop() is called from
"qemu-event"
thread. But this thread doesn't have any virIdentity set
(virIdentity being thread local) and therefore it may be unable
to open connection to secondary drivers. It is unable to do so
in split daemon scenario, because in there opening a connection
is coupled with copying current thread identity onto the
connection. Code-wise, virIdentityGetCurrent() returns NULL which
in turn makes virGetConnectGeneric() fail. This problem does not
occur in monolithic daemon scenario, because no identity copying
is done there.
Long story short, inability to open secondary driver connection
can lead to unwanted results. Therefore, do what
qemuProcessReconnectHelper() does - set the new thread identity
to be the one of the caller.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2013573
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/qemu/qemu_driver.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a8bf0ecc6f..70b5f37e6b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -571,6 +571,7 @@ qemuStateInitialize(bool privileged,
size_t i;
const char *defsecmodel = NULL;
g_autofree virSecurityManager **sec_managers = NULL;
+ g_autoptr(virIdentity) identity = virIdentityGetCurrent();
Note, qemuStateInitialize will run with the system identity, so this
is functionally the same as the next patch.
qemu_driver = g_new0(virQEMUDriver, 1);
@@ -915,7 +916,7 @@ qemuStateInitialize(bool privileged,
* events that will be dispatched to the worker pool */
qemu_driver->workerPool = virThreadPoolNewFull(0, 1, 0, qemuProcessEventHandler,
"qemu-event",
- NULL,
+ identity,
qemu_driver);
if (!qemu_driver->workerPool)
goto error;
Reviewed-by: Daniel P. Berrangé <berrange(a)redhat.com>
Regards,
Daniel
--
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9:49 a.m.
New subject: [PATCH 2/3] qemu: Set "qemu-event" thread identity
On 10/26/21 4:31 PM, Daniel P. Berrangé wrote:
On Tue, Oct 26, 2021 at 12:17:07PM +0200, Michal Privoznik wrote:
> It may happen that qemuProcessStop() is called from "qemu-event"
> thread. But this thread doesn't have any virIdentity set
> (virIdentity being thread local) and therefore it may be unable
> to open connection to secondary drivers. It is unable to do so
> in split daemon scenario, because in there opening a connection
> is coupled with copying current thread identity onto the
> connection. Code-wise, virIdentityGetCurrent() returns NULL which
> in turn makes virGetConnectGeneric() fail. This problem does not
> occur in monolithic daemon scenario, because no identity copying
> is done there.
>
> Long story short, inability to open secondary driver connection
> can lead to unwanted results. Therefore, do what
> qemuProcessReconnectHelper() does - set the new thread identity
> to be the one of the caller.
>
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2013573
> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
> ---
> src/qemu/qemu_driver.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index a8bf0ecc6f..70b5f37e6b 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -571,6 +571,7 @@ qemuStateInitialize(bool privileged,
> size_t i;
> const char *defsecmodel = NULL;
> g_autofree virSecurityManager **sec_managers = NULL;
> + g_autoptr(virIdentity) identity = virIdentityGetCurrent();
Note, qemuStateInitialize will run with the system identity, so this
is functionally the same as the next patch.
Yes, but for some reason that patch looks like a hack to me. But I can
polish it and we can go with that one instead.
Michal
5:17 a.m.
New subject: [PATCH 3/3] *** DO NOT MERGE ***
One problem with qemuProcessStop() is that it may run from
"qemu-event" thread. This thread processes events from all
guests, meaning there's just one thread that serves all running
guests. But as such has no virIdentity set, which looks correct
on the first glance - there's no identity to associate it with
anyway.
But, the problem arises when we need to connect to other daemons
(e.g. virtnetworkd) to call APIs (e.g. delete a port). Here we
want the thread to have the identity that of the guest. But since
we haven't set any identity, opening connection to secondary
drivers fails (because virIdentityGetCurrent() returns NULL which
is treated by virGetConnectGeneric() as an error).
As a terrible hack we can set the system identity.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2013573
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/qemu/qemu_process.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index d5f8a47ac2..7ae1974710 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -7888,6 +7888,7 @@ void qemuProcessStop(virQEMUDriver *driver,
g_autofree char *timestamp = NULL;
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
g_autoptr(virConnect) conn = NULL;
+ g_autoptr(virIdentity) ident = NULL;
VIR_DEBUG("Shutting down vm=%p name=%s id=%d pid=%lld, "
"reason=%s, asyncJob=%s, flags=0x%x",
@@ -7901,6 +7902,9 @@ void qemuProcessStop(virQEMUDriver *driver,
* reporting so we don't squash a legit error. */
virErrorPreserveLast(&orig_err);
+ ident = virIdentityGetSystem();
+ virIdentitySetCurrent(ident);
+
if (asyncJob != QEMU_ASYNC_JOB_NONE) {
if (qemuDomainObjBeginNestedJob(driver, vm, asyncJob) < 0)
goto cleanup;
--
2.32.0
1122
days inactive
1123
days old
9 comments
3 participants
participants (3)
-
Daniel P. Berrangé -
Michal Privoznik -
Michal Prívozník