* [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen
@ 2019-08-29 2:16 Ivan Ren
2019-09-11 11:19 ` Juan Quintela
2019-09-12 9:53 ` Dr. David Alan Gilbert
0 siblings, 2 replies; 3+ messages in thread
From: Ivan Ren @ 2019-08-29 2:16 UTC (permalink / raw)
To: quintela, dgilbert; +Cc: qemu-devel
From: Ivan Ren <ivanren@tencent.com>
When encounter error, multifd_send_thread should always notify who pay
attention to it before exit. Otherwise it may block migration_thread
at multifd_send_sync_main forever.
Error as follow:
-------------------------------------------------------------------------------
(gdb) bt
#0 0x00007f4d669dfa0b in do_futex_wait.constprop.1 () from /lib64/libpthread.so.0
#1 0x00007f4d669dfa9f in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
#2 0x00007f4d669dfb3b in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
#3 0x0000562ccf0a5614 in qemu_sem_wait (sem=sem@entry=0x562cd1b698e8) at util/qemu-thread-posix.c:319
#4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
#5 0x0000562ccecb95f4 in ram_save_iterate (f=0x562cd0ecc000, opaque=<optimized out>) at /qemu/migration/ram.c:3550
#6 0x0000562ccef43c23 in qemu_savevm_state_iterate (f=0x562cd0ecc000, postcopy=false) at migration/savevm.c:1189
#7 0x0000562ccef3dcf3 in migration_iteration_run (s=0x562cd09fabf0) at migration/migration.c:3131
#8 migration_thread (opaque=opaque@entry=0x562cd09fabf0) at migration/migration.c:3258
#9 0x0000562ccf0a4c26 in qemu_thread_start (args=<optimized out>) at util/qemu-thread-posix.c:502
#10 0x00007f4d669d9e25 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f4d6670635d in clone () from /lib64/libc.so.6
(gdb) f 4
#4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
1099 qemu_sem_wait(&p->sem_sync);
(gdb) list
1094 }
1095 for (i = 0; i < migrate_multifd_channels(); i++) {
1096 MultiFDSendParams *p = &multifd_send_state->params[i];
1097
1098 trace_multifd_send_sync_main_wait(p->id);
1099 qemu_sem_wait(&p->sem_sync);
1100 }
1101 trace_multifd_send_sync_main(multifd_send_state->packet_num);
1102 }
1103
(gdb) p i
$1 = 0
(gdb) p multifd_send_state->params[0].pending_job
$2 = 2 //It means the job before MULTIFD_FLAG_SYNC has already fail
(gdb) p multifd_send_state->params[0].quit
$3 = true
Signed-off-by: Ivan Ren <ivanren@tencent.com>
---
migration/ram.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index b01a37e7ca..0047286b7e 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1112,6 +1112,7 @@ static void *multifd_send_thread(void *opaque)
rcu_register_thread();
if (multifd_send_initial_packet(p, &local_err) < 0) {
+ ret = -1;
goto out;
}
/* initial packet */
@@ -1179,9 +1180,7 @@ out:
* who pay attention to me.
*/
if (ret != 0) {
- if (flags & MULTIFD_FLAG_SYNC) {
- qemu_sem_post(&p->sem_sync);
- }
+ qemu_sem_post(&p->sem_sync);
qemu_sem_post(&multifd_send_state->channels_ready);
}
--
2.17.2 (Apple Git-113)
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen
2019-08-29 2:16 [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen Ivan Ren
@ 2019-09-11 11:19 ` Juan Quintela
2019-09-12 9:53 ` Dr. David Alan Gilbert
1 sibling, 0 replies; 3+ messages in thread
From: Juan Quintela @ 2019-09-11 11:19 UTC (permalink / raw)
To: Ivan Ren; +Cc: dgilbert, qemu-devel
Ivan Ren <renyime@gmail.com> wrote:
> From: Ivan Ren <ivanren@tencent.com>
>
> When encounter error, multifd_send_thread should always notify who pay
> attention to it before exit. Otherwise it may block migration_thread
> at multifd_send_sync_main forever.
>
> Error as follow:
> -------------------------------------------------------------------------------
> (gdb) bt
> #0 0x00007f4d669dfa0b in do_futex_wait.constprop.1 () from /lib64/libpthread.so.0
> #1 0x00007f4d669dfa9f in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
> #2 0x00007f4d669dfb3b in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
> #3 0x0000562ccf0a5614 in qemu_sem_wait (sem=sem@entry=0x562cd1b698e8) at util/qemu-thread-posix.c:319
> #4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
> #5 0x0000562ccecb95f4 in ram_save_iterate (f=0x562cd0ecc000, opaque=<optimized out>) at /qemu/migration/ram.c:3550
> #6 0x0000562ccef43c23 in qemu_savevm_state_iterate (f=0x562cd0ecc000, postcopy=false) at migration/savevm.c:1189
> #7 0x0000562ccef3dcf3 in migration_iteration_run (s=0x562cd09fabf0) at migration/migration.c:3131
> #8 migration_thread (opaque=opaque@entry=0x562cd09fabf0) at migration/migration.c:3258
> #9 0x0000562ccf0a4c26 in qemu_thread_start (args=<optimized out>) at util/qemu-thread-posix.c:502
> #10 0x00007f4d669d9e25 in start_thread () from /lib64/libpthread.so.0
> #11 0x00007f4d6670635d in clone () from /lib64/libc.so.6
> (gdb) f 4
> #4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
> 1099 qemu_sem_wait(&p->sem_sync);
> (gdb) list
> 1094 }
> 1095 for (i = 0; i < migrate_multifd_channels(); i++) {
> 1096 MultiFDSendParams *p = &multifd_send_state->params[i];
> 1097
> 1098 trace_multifd_send_sync_main_wait(p->id);
> 1099 qemu_sem_wait(&p->sem_sync);
> 1100 }
> 1101 trace_multifd_send_sync_main(multifd_send_state->packet_num);
> 1102 }
> 1103
> (gdb) p i
> $1 = 0
> (gdb) p multifd_send_state->params[0].pending_job
> $2 = 2 //It means the job before MULTIFD_FLAG_SYNC has already fail
> (gdb) p multifd_send_state->params[0].quit
> $3 = true
>
> Signed-off-by: Ivan Ren <ivanren@tencent.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen
2019-08-29 2:16 [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen Ivan Ren
2019-09-11 11:19 ` Juan Quintela
@ 2019-09-12 9:53 ` Dr. David Alan Gilbert
1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-12 9:53 UTC (permalink / raw)
To: Ivan Ren; +Cc: qemu-devel, quintela
Queued
* Ivan Ren (renyime@gmail.com) wrote:
> From: Ivan Ren <ivanren@tencent.com>
>
> When encounter error, multifd_send_thread should always notify who pay
> attention to it before exit. Otherwise it may block migration_thread
> at multifd_send_sync_main forever.
>
> Error as follow:
> -------------------------------------------------------------------------------
> (gdb) bt
> #0 0x00007f4d669dfa0b in do_futex_wait.constprop.1 () from /lib64/libpthread.so.0
> #1 0x00007f4d669dfa9f in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
> #2 0x00007f4d669dfb3b in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
> #3 0x0000562ccf0a5614 in qemu_sem_wait (sem=sem@entry=0x562cd1b698e8) at util/qemu-thread-posix.c:319
> #4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
> #5 0x0000562ccecb95f4 in ram_save_iterate (f=0x562cd0ecc000, opaque=<optimized out>) at /qemu/migration/ram.c:3550
> #6 0x0000562ccef43c23 in qemu_savevm_state_iterate (f=0x562cd0ecc000, postcopy=false) at migration/savevm.c:1189
> #7 0x0000562ccef3dcf3 in migration_iteration_run (s=0x562cd09fabf0) at migration/migration.c:3131
> #8 migration_thread (opaque=opaque@entry=0x562cd09fabf0) at migration/migration.c:3258
> #9 0x0000562ccf0a4c26 in qemu_thread_start (args=<optimized out>) at util/qemu-thread-posix.c:502
> #10 0x00007f4d669d9e25 in start_thread () from /lib64/libpthread.so.0
> #11 0x00007f4d6670635d in clone () from /lib64/libc.so.6
> (gdb) f 4
> #4 0x0000562ccecb4752 in multifd_send_sync_main (rs=<optimized out>) at /qemu/migration/ram.c:1099
> 1099 qemu_sem_wait(&p->sem_sync);
> (gdb) list
> 1094 }
> 1095 for (i = 0; i < migrate_multifd_channels(); i++) {
> 1096 MultiFDSendParams *p = &multifd_send_state->params[i];
> 1097
> 1098 trace_multifd_send_sync_main_wait(p->id);
> 1099 qemu_sem_wait(&p->sem_sync);
> 1100 }
> 1101 trace_multifd_send_sync_main(multifd_send_state->packet_num);
> 1102 }
> 1103
> (gdb) p i
> $1 = 0
> (gdb) p multifd_send_state->params[0].pending_job
> $2 = 2 //It means the job before MULTIFD_FLAG_SYNC has already fail
> (gdb) p multifd_send_state->params[0].quit
> $3 = true
>
> Signed-off-by: Ivan Ren <ivanren@tencent.com>
> ---
> migration/ram.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index b01a37e7ca..0047286b7e 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1112,6 +1112,7 @@ static void *multifd_send_thread(void *opaque)
> rcu_register_thread();
>
> if (multifd_send_initial_packet(p, &local_err) < 0) {
> + ret = -1;
> goto out;
> }
> /* initial packet */
> @@ -1179,9 +1180,7 @@ out:
> * who pay attention to me.
> */
> if (ret != 0) {
> - if (flags & MULTIFD_FLAG_SYNC) {
> - qemu_sem_post(&p->sem_sync);
> - }
> + qemu_sem_post(&p->sem_sync);
> qemu_sem_post(&multifd_send_state->channels_ready);
> }
>
> --
> 2.17.2 (Apple Git-113)
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-08-29 2:16 [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen Ivan Ren
2019-09-11 11:19 ` Juan Quintela
2019-09-12 9:53 ` Dr. David Alan Gilbert
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