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[PATCH] cpuset: don't need to mark cpuset_mems_generation atomic
Drop the atomic_t marking on the cpuset static global cpuset_mems_generation. Since all access to it is guarded by the global manage_mutex, there is no need for further serialization of this value. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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8488bc359d
commit
151a44202d
1 changed files with 11 additions and 8 deletions
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@ -149,7 +149,7 @@ static inline int is_spread_slab(const struct cpuset *cs)
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}
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}
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/*
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/*
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* Increment this atomic integer everytime any cpuset changes its
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* Increment this integer everytime any cpuset changes its
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* mems_allowed value. Users of cpusets can track this generation
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* mems_allowed value. Users of cpusets can track this generation
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* number, and avoid having to lock and reload mems_allowed unless
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* number, and avoid having to lock and reload mems_allowed unless
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* the cpuset they're using changes generation.
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* the cpuset they're using changes generation.
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@ -163,8 +163,11 @@ static inline int is_spread_slab(const struct cpuset *cs)
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* on every visit to __alloc_pages(), to efficiently check whether
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* on every visit to __alloc_pages(), to efficiently check whether
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* its current->cpuset->mems_allowed has changed, requiring an update
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* its current->cpuset->mems_allowed has changed, requiring an update
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* of its current->mems_allowed.
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* of its current->mems_allowed.
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*
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* Since cpuset_mems_generation is guarded by manage_mutex,
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* there is no need to mark it atomic.
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*/
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*/
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static atomic_t cpuset_mems_generation = ATOMIC_INIT(1);
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static int cpuset_mems_generation;
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static struct cpuset top_cpuset = {
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static struct cpuset top_cpuset = {
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.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
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.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
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@ -877,7 +880,7 @@ static int update_nodemask(struct cpuset *cs, char *buf)
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mutex_lock(&callback_mutex);
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mutex_lock(&callback_mutex);
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cs->mems_allowed = trialcs.mems_allowed;
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cs->mems_allowed = trialcs.mems_allowed;
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cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
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cs->mems_generation = cpuset_mems_generation++;
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mutex_unlock(&callback_mutex);
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mutex_unlock(&callback_mutex);
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set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */
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set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */
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@ -1270,11 +1273,11 @@ static ssize_t cpuset_common_file_write(struct file *file, const char __user *us
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break;
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break;
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case FILE_SPREAD_PAGE:
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case FILE_SPREAD_PAGE:
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retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
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retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
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cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
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cs->mems_generation = cpuset_mems_generation++;
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break;
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break;
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case FILE_SPREAD_SLAB:
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case FILE_SPREAD_SLAB:
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retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
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retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
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cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
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cs->mems_generation = cpuset_mems_generation++;
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break;
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break;
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case FILE_TASKLIST:
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case FILE_TASKLIST:
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retval = attach_task(cs, buffer, &pathbuf);
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retval = attach_task(cs, buffer, &pathbuf);
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@ -1823,7 +1826,7 @@ static long cpuset_create(struct cpuset *parent, const char *name, int mode)
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atomic_set(&cs->count, 0);
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atomic_set(&cs->count, 0);
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INIT_LIST_HEAD(&cs->sibling);
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INIT_LIST_HEAD(&cs->sibling);
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INIT_LIST_HEAD(&cs->children);
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INIT_LIST_HEAD(&cs->children);
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cs->mems_generation = atomic_inc_return(&cpuset_mems_generation);
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cs->mems_generation = cpuset_mems_generation++;
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fmeter_init(&cs->fmeter);
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fmeter_init(&cs->fmeter);
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cs->parent = parent;
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cs->parent = parent;
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@ -1913,7 +1916,7 @@ int __init cpuset_init_early(void)
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struct task_struct *tsk = current;
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struct task_struct *tsk = current;
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tsk->cpuset = &top_cpuset;
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tsk->cpuset = &top_cpuset;
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tsk->cpuset->mems_generation = atomic_inc_return(&cpuset_mems_generation);
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tsk->cpuset->mems_generation = cpuset_mems_generation++;
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return 0;
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return 0;
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}
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}
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@ -1932,7 +1935,7 @@ int __init cpuset_init(void)
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top_cpuset.mems_allowed = NODE_MASK_ALL;
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top_cpuset.mems_allowed = NODE_MASK_ALL;
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fmeter_init(&top_cpuset.fmeter);
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fmeter_init(&top_cpuset.fmeter);
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top_cpuset.mems_generation = atomic_inc_return(&cpuset_mems_generation);
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top_cpuset.mems_generation = cpuset_mems_generation++;
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init_task.cpuset = &top_cpuset;
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init_task.cpuset = &top_cpuset;
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