We allocate and zero cpu_isolated_map after the isolcpus __setup option
has run. This means cpu_isolated_map always ends up empty and if
CPUMASK_OFFSTACK is enabled we write to a cpumask that hasn't been
allocated.
To keep the fix to a minimum this patch stores a pointer to the cmdline
option and parses it after we allocate and zero the cpumask.
Signed-off-by: Anton Blanchard <[email protected]>
---
Might be worth moving cpu_isolated_map into kernel/cpu.c and treat it
like the other cpu masks but I figured that change would have trouble
making 2.6.32. Thoughts?
Index: linux.trees.git/kernel/sched.c
===================================================================
--- linux.trees.git.orig/kernel/sched.c 2009-11-28 09:35:29.000000000 +1100
+++ linux.trees.git/kernel/sched.c 2009-11-28 21:50:44.000000000 +1100
@@ -8098,10 +8098,14 @@ cpu_attach_domain(struct sched_domain *s
/* cpus with isolated domains */
static cpumask_var_t cpu_isolated_map;
-/* Setup the mask of cpus configured for isolated domains */
+/*
+ * Since it's too early to allocate cpu_isolated_map we just store
+ * a pointer to the parameter and allocate and initialize it in sched_init
+ */
+static __initdata char *isolated_cpu_str;
static int __init isolated_cpu_setup(char *str)
{
- cpulist_parse(str, cpu_isolated_map);
+ isolated_cpu_str = str;
return 1;
}
@@ -9650,6 +9654,7 @@ void __init sched_init(void)
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
#endif
zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ cpulist_parse(isolated_cpu_str, cpu_isolated_map);
#endif /* SMP */
perf_event_init();
On Mon, 2009-11-30 at 11:05 +1100, Anton Blanchard wrote:
> Might be worth moving cpu_isolated_map into kernel/cpu.c and treat it
> like the other cpu masks but I figured that change would have trouble
> making 2.6.32. Thoughts?
I'd love to kill off isolcpus in favour of exclusive cpusets, except
that we need a bit more work on the latter to really make that happen.
On Mon, 30 Nov 2009 10:35:32 am Anton Blanchard wrote:
>
> We allocate and zero cpu_isolated_map after the isolcpus __setup option
> has run. This means cpu_isolated_map always ends up empty and if
> CPUMASK_OFFSTACK is enabled we write to a cpumask that hasn't been
> allocated.
>
> To keep the fix to a minimum this patch stores a pointer to the cmdline
> option and parses it after we allocate and zero the cpumask.
I introduced this regression in:
commit 49557e620339cb134127b5bfbcfecc06b77d0232
Author: Rusty Russell <[email protected]>
Date: Mon Nov 2 20:37:20 2009 +1030
sched: Fix boot crash by zalloc()ing most of the cpu masks
But this change made isolcpus= never work, CPUMASK_OFFSTACK or no.
Your patch works and is minimal.
Acked-by: Rusty Russell <[email protected]>
Thanks,
Rusty.
PS. This would have also worked:
diff --git a/kernel/sched.c b/kernel/sched.c
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8045,6 +8045,7 @@ static cpumask_var_t cpu_isolated_map;
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
+ alloc_bootmem_cpumask_var(&cpu_isolated_map);
cpulist_parse(str, cpu_isolated_map);
return 1;
}
@@ -9571,7 +9572,9 @@ void __init sched_init(void)
zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
#endif
- zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ /* May be allocated at isolcpus cmdline parse time */
+ if (cpu_isolated_map == NULL)
+ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */
perf_event_init();
On Mon, 30 Nov 2009 10:35:32 am Anton Blanchard wrote:
> We allocate and zero cpu_isolated_map after the isolcpus __setup option
> has run. This means cpu_isolated_map always ends up empty and if
> CPUMASK_OFFSTACK is enabled we write to a cpumask that hasn't been
> allocated.
I introduced this regression in 49557e620339cb13 (sched: Fix boot
crash by zalloc()ing most of the cpu masks).
Use the bootmem allocator if they set isolcpus=, otherwise allocate
and zero like normal.
Reported-by: Anton Blanchard <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>
Tested-by: Anton Blanchard <[email protected]>
Cc: [email protected]
diff --git a/kernel/sched.c b/kernel/sched.c
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8045,6 +8045,7 @@ static cpumask_var_t cpu_isolated_map;
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
+ alloc_bootmem_cpumask_var(&cpu_isolated_map);
cpulist_parse(str, cpu_isolated_map);
return 1;
}
@@ -9571,7 +9572,9 @@ void __init sched_init(void)
zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
#endif
- zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ /* May be allocated at isolcpus cmdline parse time */
+ if (cpu_isolated_map == NULL)
+ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */
perf_event_init();
Commit-ID: bdddd2963c0264c56f18043f6fa829d3c1d3d1c0
Gitweb: http://git.kernel.org/tip/bdddd2963c0264c56f18043f6fa829d3c1d3d1c0
Author: Rusty Russell <[email protected]>
AuthorDate: Wed, 2 Dec 2009 14:09:16 +1030
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 2 Dec 2009 10:27:16 +0100
sched: Fix isolcpus boot option
Anton Blanchard wrote:
> We allocate and zero cpu_isolated_map after the isolcpus
> __setup option has run. This means cpu_isolated_map always
> ends up empty and if CPUMASK_OFFSTACK is enabled we write to a
> cpumask that hasn't been allocated.
I introduced this regression in 49557e620339cb13 (sched: Fix
boot crash by zalloc()ing most of the cpu masks).
Use the bootmem allocator if they set isolcpus=, otherwise
allocate and zero like normal.
Reported-by: Anton Blanchard <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Anton Blanchard <[email protected]>
---
kernel/sched.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 1031cae..4883fee 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8061,6 +8061,7 @@ static cpumask_var_t cpu_isolated_map;
/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
+ alloc_bootmem_cpumask_var(&cpu_isolated_map);
cpulist_parse(str, cpu_isolated_map);
return 1;
}
@@ -9609,7 +9610,9 @@ void __init sched_init(void)
zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
#endif
- zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ /* May be allocated at isolcpus cmdline parse time */
+ if (cpu_isolated_map == NULL)
+ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */
perf_event_init();