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| author | Paul Jackson <pj@sgi.com> | 2006-01-08 01:02:01 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-08 20:13:44 -0800 |
| commit | c417f0242ebe578924a30d4e53d35b5059fed4e7 (patch) | |
| tree | 3058c7c79aedb11e7013f5faca34eb07e9a761bd | |
| parent | 04c19fa6f16047abff2288ddbc1f0798ede5a849 (diff) | |
| download | lwn-c417f0242ebe578924a30d4e53d35b5059fed4e7.tar.gz lwn-c417f0242ebe578924a30d4e53d35b5059fed4e7.zip | |
[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>
| -rw-r--r-- | include/linux/cpuset.h | 2 | ||||
| -rw-r--r-- | init/main.c | 1 | ||||
| -rw-r--r-- | kernel/cpuset.c | 22 |
3 files changed, 19 insertions, 6 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 34081c168af5..c472f972bd6d 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -16,6 +16,7 @@ extern int number_of_cpusets; /* How many cpusets are defined in system? */ +extern int cpuset_init_early(void); extern int cpuset_init(void); extern void cpuset_init_smp(void); extern void cpuset_fork(struct task_struct *p); @@ -49,6 +50,7 @@ extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer); #else /* !CONFIG_CPUSETS */ +static inline int cpuset_init_early(void) { return 0; } static inline int cpuset_init(void) { return 0; } static inline void cpuset_init_smp(void) {} static inline void cpuset_fork(struct task_struct *p) {} diff --git a/init/main.c b/init/main.c index 2ed3638deec7..afe5eb84ad52 100644 --- a/init/main.c +++ b/init/main.c @@ -512,6 +512,7 @@ asmlinkage void __init start_kernel(void) } #endif vfs_caches_init_early(); + cpuset_init_early(); mem_init(); kmem_cache_init(); setup_per_cpu_pageset(); diff --git a/kernel/cpuset.c b/kernel/cpuset.c index cf8203a5fa71..fc949e4a625c 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 * |