[PATCH] Avoid race in schedule() when switching schedulers

[PATCH] Avoid race in schedule() when switching schedulers

[Juergen Gross]

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Selecting the scheduler to call must be done under lock. Otherwise a race
might occur when switching schedulers in a cpupool

Signed-off-by: juergen.gross@ts.fujitsu.com


1 file changed, 2 insertions(+), 1 deletion(-)
xen/common/schedule.c |    3 ++-



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# HG changeset patch
# User Juergen Gross <juergen.gross@ts.fujitsu.com>
# Date 1315910154 -7200
# Node ID 86f2a3a45ecbcc49aba88d06bf13bbcaf5a9b89b
# Parent  64aab9a077ea937b31fd678b02f755139b924184
Avoid race in schedule() when switching schedulers

Selecting the scheduler to call must be done under lock. Otherwise a race
might occur when switching schedulers in a cpupool

Signed-off-by: juergen.gross@ts.fujitsu.com

diff -r 64aab9a077ea -r 86f2a3a45ecb xen/common/schedule.c
--- a/xen/common/schedule.c	Tue Sep 13 11:20:57 2011 +0100
+++ b/xen/common/schedule.c	Tue Sep 13 12:35:54 2011 +0200
@@ -1107,7 +1107,7 @@ static void schedule(void)
 {
     struct vcpu          *prev = current, *next = NULL;
     s_time_t              now = NOW();
-    struct scheduler     *sched = this_cpu(scheduler);
+    struct scheduler     *sched;
     unsigned long        *tasklet_work = &this_cpu(tasklet_work_to_do);
     bool_t                tasklet_work_scheduled = 0;
     struct schedule_data *sd;
@@ -1141,6 +1141,7 @@ static void schedule(void)
     stop_timer(&sd->s_timer);
     
     /* get policy-specific decision on scheduling... */
+    sched = this_cpu(scheduler);
     next_slice = sched->do_schedule(sched, now, tasklet_work_scheduled);
 
     next = next_slice.task;

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Re: [PATCH] Avoid race in schedule() when switching schedulers

[George Dunlap]

Acked-by: George Dunlap <george.dunlap@eu.citrix.com>

On Tue, Sep 13, 2011 at 11:36 AM, Juergen Gross
<juergen.gross@ts.fujitsu.com> wrote:
> Selecting the scheduler to call must be done under lock. Otherwise a race
> might occur when switching schedulers in a cpupool
>
> Signed-off-by: juergen.gross@ts.fujitsu.com
>
>
> 1 file changed, 2 insertions(+), 1 deletion(-)
> xen/common/schedule.c |    3 ++-
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
>