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cpuset: fix regression when failed to generate sched domains

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Impact: properly rebuild sched-domains on kmalloc() failure

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 was introduced by:

| commit dfb512ec48
| Author: Max Krasnyansky <maxk@qualcomm.com>
| 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@cn.fujitsu.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan
2008-11-18 14:02:03 +08:00
committed by Ingo Molnar
parent ad133ba3dc
commit 700018e0a7
2 changed files with 15 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
kernel/cpuset.c
View File

@@ -587,7 +587,6 @@ static int generate_sched_domains(cpumask_t **domains,
int ndoms; /* number of sched domains in result */ int ndoms; /* number of sched domains in result */
int nslot; /* next empty doms[] cpumask_t slot */ int nslot; /* next empty doms[] cpumask_t slot */
ndoms = 0;
doms = NULL; doms = NULL;
dattr = NULL; dattr = NULL;
csa = NULL; csa = NULL;
@@ -674,10 +673,8 @@ restart:
* Convert <csn, csa> to <ndoms, doms> and populate cpu masks. * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
*/ */
doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL); doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
if (!doms) { if (!doms)
ndoms = 0;
goto done; goto done;
}
/* /*
* The rest of the code, including the scheduler, can deal with * The rest of the code, including the scheduler, can deal with
@@ -732,6 +729,13 @@ restart:
done: done:
kfree(csa); kfree(csa);
/*
* Fallback to the default domain if kmalloc() failed.
* See comments in partition_sched_domains().
*/
if (doms == NULL)
ndoms = 1;
*domains = doms; *domains = doms;
*attributes = dattr; *attributes = dattr;
return ndoms; return ndoms;

13
kernel/sched.c
View File

@@ -7789,13 +7789,14 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
* *
* The passed in 'doms_new' should be kmalloc'd. This routine takes * 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 * 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, * failed the kmalloc call, then it can pass in doms_new == NULL &&
* and partition_sched_domains() will fallback to the single partition * ndoms_new == 1, and partition_sched_domains() will fallback to
* 'fallback_doms', it also forces the domains to be rebuilt. * 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. * If doms_new == NULL it will be replaced with cpu_online_map.
* ndoms_new==0 is a special case for destroying existing domains. * ndoms_new == 0 is a special case for destroying existing domains,
* It will not create the default domain. * and it will not create the default domain.
* *
* Call with hotplug lock held * Call with hotplug lock held
*/ */