The patch titled
cpuset: fix regression when failed to generate sched domains
has been added to the -mm tree. Its filename is
cpuset-fix-regression-when-failed-to-generate-sched-domains.patch
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Subject: cpuset: fix regression when failed to generate sched domains
From: Li Zefan <lizf@xxxxxxxxxxxxxx>
When cpuset failed to generate sched domains due to kmalloc() failure, the
scheduler should fallback to the single partition 'fallback_doms' and
rebuild sched domains, but now it only destroys but not rebuilds sched
domains.
The regression is introduced by:
commit dfb512ec4834116124da61d6c1ee10fd0aa32bd6
Author: Max Krasnyansky <maxk@xxxxxxxxxxxx>
Date: Fri Aug 29 13:11:41 2008 -0700
sched: arch_reinit_sched_domains() must destroy domains to force rebuild
After the above commit, partition_sched_domains(0, NULL, NULL) will
only destroy sched domains and partition_sched_domains(1, NULL, NULL)
will create the default sched domain.
Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Max Krasnyansky <maxk@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.27.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cpuset.c | 12 ++++++++----
kernel/sched.c | 13 +++++++------
2 files changed, 15 insertions(+), 10 deletions(-)
diff -puN kernel/cpuset.c~cpuset-fix-regression-when-failed-to-generate-sched-domains kernel/cpuset.c
--- a/kernel/cpuset.c~cpuset-fix-regression-when-failed-to-generate-sched-domains
+++ a/kernel/cpuset.c
@@ -588,7 +588,6 @@ static int generate_sched_domains(cpumas
int ndoms; /* number of sched domains in result */
int nslot; /* next empty doms[] cpumask_t slot */
- ndoms = 0;
doms = NULL;
dattr = NULL;
csa = NULL;
@@ -675,10 +674,8 @@ restart:
* Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
*/
doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
- if (!doms) {
- ndoms = 0;
+ if (!doms)
goto done;
- }
/*
* The rest of the code, including the scheduler, can deal with
@@ -733,6 +730,13 @@ restart:
done:
kfree(csa);
+ /*
+ * Fallback to the default domain if kmalloc() failed.
+ * See comments in partition_sched_domains().
+ */
+ if (doms == NULL)
+ ndoms = 1;
+
*domains = doms;
*attributes = dattr;
return ndoms;
diff -puN kernel/sched.c~cpuset-fix-regression-when-failed-to-generate-sched-domains kernel/sched.c
--- a/kernel/sched.c~cpuset-fix-regression-when-failed-to-generate-sched-domains
+++ a/kernel/sched.c
@@ -7798,13 +7798,14 @@ static int dattrs_equal(struct sched_dom
*
* The passed in 'doms_new' should be kmalloc'd. This routine takes
* ownership of it and will kfree it when done with it. If the caller
- * failed the kmalloc call, then it can pass in doms_new == NULL,
- * and partition_sched_domains() will fallback to the single partition
- * 'fallback_doms', it also forces the domains to be rebuilt.
+ * failed the kmalloc call, then it can pass in doms_new == NULL &&
+ * ndoms_new == 1, and partition_sched_domains() will fallback to
+ * the single partition 'fallback_doms', it also forces the domains
+ * to be rebuilt.
*
- * If doms_new==NULL it will be replaced with cpu_online_map.
- * ndoms_new==0 is a special case for destroying existing domains.
- * It will not create the default domain.
+ * If doms_new == NULL it will be replaced with cpu_online_map.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
*
* Call with hotplug lock held
*/
_
Patches currently in -mm which might be from lizf@xxxxxxxxxxxxxx are
linux-next.patch
cgroup-fix-potential-deadlock-in-pre_destroy-v2.patch
cpuset-fix-regression-when-failed-to-generate-sched-domains.patch
memcg-memory-hotplug-fix-for-notifier-callback.patch
memcg-reduce-size-of-mem_cgroup-by-using-nr_cpu_ids.patch
memcg-new-force_empty-to-free-pages-under-group.patch
memcg-handle-swap-caches.patch
memcg-memswap-controller-kconfig.patch
memcg-swap-cgroup-for-remembering-usage.patch
memcg-swap-cgroup-for-remembering-usage-fix.patch
memcg-swap-cgroup-for-remembering-usage-fix-2.patch
memcg-swap-cgroup-for-remembering-usage-fix-3.patch
memcg-memswap-controller-core.patch
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
memcg-synchronized-lru.patch
memcg-add-mem_cgroup_disabled.patch
memcg-add-mem_cgroup_disabled-fix.patch
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