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authorPaul Jackson <pj@sgi.com>2006-01-08 01:02:01 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:44 -0800
commitc417f0242ebe578924a30d4e53d35b5059fed4e7 (patch)
tree3058c7c79aedb11e7013f5faca34eb07e9a761bd /kernel/cpuset.c
parent04c19fa6f16047abff2288ddbc1f0798ede5a849 (diff)
downloadop-kernel-dev-c417f0242ebe578924a30d4e53d35b5059fed4e7.zip
op-kernel-dev-c417f0242ebe578924a30d4e53d35b5059fed4e7.tar.gz
[PATCH] cpuset: remove test for null cpuset from alloc code path
Remove a couple of more lines of code from the cpuset hooks in the page allocation code path. There was a check for a NULL cpuset pointer in the routine cpuset_update_task_memory_state() that was only needed during system boot, after the memory subsystem was initialized, before the cpuset subsystem was initialized, to catch a NULL task->cpuset pointer. Add a cpuset_init_early() routine, just before the mem_init() call in init/main.c, that sets up just enough of the init tasks cpuset structure to render cpuset_update_task_memory_state() calls harmless. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/cpuset.c')
-rw-r--r--kernel/cpuset.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index cf8203a..fc949e4 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -603,9 +603,7 @@ static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
* Do not call this routine if in_interrupt().
*
* Call without callback_sem or task_lock() held. May be called
- * with or without manage_sem held. Except in early boot or
- * an exiting task, when tsk->cpuset is NULL, this routine will
- * acquire task_lock(). We don't need to use task_lock to guard
+ * with or without manage_sem held. Doesn't need task_lock to guard
* against another task changing a non-NULL cpuset pointer to NULL,
* as that is only done by a task on itself, and if the current task
* is here, it is not simultaneously in the exit code NULL'ing its
@@ -631,9 +629,6 @@ void cpuset_update_task_memory_state()
struct task_struct *tsk = current;
struct cpuset *cs = tsk->cpuset;
- if (unlikely(!cs))
- return;
-
task_lock(tsk);
my_cpusets_mem_gen = cs->mems_generation;
task_unlock(tsk);
@@ -1836,6 +1831,21 @@ static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
return 0;
}
+/*
+ * cpuset_init_early - just enough so that the calls to
+ * cpuset_update_task_memory_state() in early init code
+ * are harmless.
+ */
+
+int __init cpuset_init_early(void)
+{
+ struct task_struct *tsk = current;
+
+ tsk->cpuset = &top_cpuset;
+ tsk->cpuset->mems_generation = atomic_read(&cpuset_mems_generation);
+ return 0;
+}
+
/**
* cpuset_init - initialize cpusets at system boot
*
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