From: Juan Quintela <quintela@redhat.com>
To: Ivan Ren <renyime@gmail.com>
Cc: dgilbert@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] migration: multifd_send_thread always post p->sem_sync when error happen
Date: Wed, 11 Sep 2019 13:19:49 +0200 [thread overview]
Message-ID: <8736h3w04q.fsf@trasno.org> (raw)
In-Reply-To: <1567044996-2362-1-git-send-email-ivanren@tencent.com> (Ivan Ren's message of "Thu, 29 Aug 2019 10:16:36 +0800")
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>
next prev parent reply other threads:[~2019-09-11 11:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
2019-09-12 9:53 ` Dr. David Alan Gilbert
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