Patchwork [resend] fix 100% cpu utilization when cpu is stopped

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Submitter Paolo Bonzini
Date April 6, 2010, 10:11 p.m.
Message ID <1270591869-11602-1-git-send-email-pbonzini@redhat.com>
Download mbox | patch
Permalink /patch/49549/
State New
Headers show

Comments

Paolo Bonzini - April 6, 2010, 10:11 p.m.
> Hello,
>
> d6f4ade (disentangle tcg and deadline calculation, 2010-03-10)
> introduces following regression(s):
>
> 100% cpu utilization when QEMU is invoked like:
> qemu -S -s ...
>
> ditto when gdb takes control over the session via gdb-stub
> (i.e. the breakpoint is hit or C-c is pressed inside gdb to
>   interrupt the attached qemu instance)

The bug is that env->stopped is not really as comprehensive as it seems to
be (and cpu_has_work thinks); it is only valid with iothread basically,
and even then it is cleared by reset and it is not set when starting
qemu with -S.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: malc <av1474@comtv.ru>
---
 cpus.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

Patch

diff --git a/cpus.c b/cpus.c
index a2e0642..0debe77 100644
--- a/cpus.c
+++ b/cpus.c
@@ -100,9 +100,7 @@  static int cpu_can_run(CPUState *env)
 {
     if (env->stop)
         return 0;
-    if (env->stopped)
-        return 0;
-    if (!vm_running)
+    if (env->stopped || !vm_running)
         return 0;
     return 1;
 }
@@ -111,7 +109,7 @@  static int cpu_has_work(CPUState *env)
 {
     if (env->stop)
         return 1;
-    if (env->stopped)
+    if (env->stopped || !vm_running)
         return 0;
     if (!env->halted)
         return 1;