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Message-ID: <20121108153512.GM31821@dhcp22.suse.cz>
Date: Thu, 8 Nov 2012 16:35:12 +0100
From: Michal Hocko <mhocko@...e.cz>
To: David Rientjes <rientjes@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Anton Vorontsov <anton.vorontsov@...aro.org>,
Oleg Nesterov <oleg@...hat.com>, linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Subject: Re: [patch 1/2] mm, oom: change type of oom_score_adj to short
On Thu 08-11-12 01:26:57, David Rientjes wrote:
> The maximum oom_score_adj is 1000 and the minimum oom_score_adj is -1000,
> so this range can be represented by the signed short type with no
> functional change. The extra space this frees up in struct signal_struct
> will be used for per-thread oom kill flags in the next patch.
>
> Signed-off-by: David Rientjes <rientjes@...gle.com>
Reviewed-by: Michal Hocko <mhocko@...e.cz>
> ---
> drivers/staging/android/lowmemorykiller.c | 16 ++++++++--------
> fs/proc/base.c | 10 +++++-----
> include/linux/oom.h | 4 ++--
> include/linux/sched.h | 6 +++---
> include/trace/events/oom.h | 4 ++--
> include/trace/events/task.h | 8 ++++----
> mm/ksm.c | 2 +-
> mm/oom_kill.c | 10 +++++-----
> mm/swapfile.c | 2 +-
> 9 files changed, 31 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
> --- a/drivers/staging/android/lowmemorykiller.c
> +++ b/drivers/staging/android/lowmemorykiller.c
> @@ -40,7 +40,7 @@
> #include <linux/notifier.h>
>
> static uint32_t lowmem_debug_level = 2;
> -static int lowmem_adj[6] = {
> +static short lowmem_adj[6] = {
> 0,
> 1,
> 6,
> @@ -70,9 +70,9 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
> int rem = 0;
> int tasksize;
> int i;
> - int min_score_adj = OOM_SCORE_ADJ_MAX + 1;
> + short min_score_adj = OOM_SCORE_ADJ_MAX + 1;
> int selected_tasksize = 0;
> - int selected_oom_score_adj;
> + short selected_oom_score_adj;
> int array_size = ARRAY_SIZE(lowmem_adj);
> int other_free = global_page_state(NR_FREE_PAGES);
> int other_file = global_page_state(NR_FILE_PAGES) -
> @@ -90,7 +90,7 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
> }
> }
> if (sc->nr_to_scan > 0)
> - lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
> + lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %hd\n",
> sc->nr_to_scan, sc->gfp_mask, other_free,
> other_file, min_score_adj);
> rem = global_page_state(NR_ACTIVE_ANON) +
> @@ -107,7 +107,7 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
> rcu_read_lock();
> for_each_process(tsk) {
> struct task_struct *p;
> - int oom_score_adj;
> + short oom_score_adj;
>
> if (tsk->flags & PF_KTHREAD)
> continue;
> @@ -141,11 +141,11 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
> selected = p;
> selected_tasksize = tasksize;
> selected_oom_score_adj = oom_score_adj;
> - lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
> + lowmem_print(2, "select %d (%s), adj %hd, size %d, to kill\n",
> p->pid, p->comm, oom_score_adj, tasksize);
> }
> if (selected) {
> - lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
> + lowmem_print(1, "send sigkill to %d (%s), adj %hd, size %d\n",
> selected->pid, selected->comm,
> selected_oom_score_adj, selected_tasksize);
> lowmem_deathpending_timeout = jiffies + HZ;
> @@ -176,7 +176,7 @@ static void __exit lowmem_exit(void)
> }
>
> module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
> -module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size,
> +module_param_array_named(adj, lowmem_adj, short, &lowmem_adj_size,
> S_IRUGO | S_IWUSR);
> module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
> S_IRUGO | S_IWUSR);
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -878,7 +878,7 @@ static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
> {
> struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
> char buffer[PROC_NUMBUF];
> - int oom_score_adj = OOM_SCORE_ADJ_MIN;
> + short oom_score_adj = OOM_SCORE_ADJ_MIN;
> unsigned long flags;
> size_t len;
>
> @@ -889,7 +889,7 @@ static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
> unlock_task_sighand(task, &flags);
> }
> put_task_struct(task);
> - len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj);
> + len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
> return simple_read_from_buffer(buf, count, ppos, buffer, len);
> }
>
> @@ -936,15 +936,15 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
> goto err_task_lock;
> }
>
> - if (oom_score_adj < task->signal->oom_score_adj_min &&
> + if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
> !capable(CAP_SYS_RESOURCE)) {
> err = -EACCES;
> goto err_sighand;
> }
>
> - task->signal->oom_score_adj = oom_score_adj;
> + task->signal->oom_score_adj = (short)oom_score_adj;
> if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
> - task->signal->oom_score_adj_min = oom_score_adj;
> + task->signal->oom_score_adj_min = (short)oom_score_adj;
> trace_oom_score_adj_update(task);
>
> err_sighand:
> diff --git a/include/linux/oom.h b/include/linux/oom.h
> --- a/include/linux/oom.h
> +++ b/include/linux/oom.h
> @@ -29,8 +29,8 @@ enum oom_scan_t {
> OOM_SCAN_SELECT, /* always select this thread first */
> };
>
> -extern void compare_swap_oom_score_adj(int old_val, int new_val);
> -extern int test_set_oom_score_adj(int new_val);
> +extern void compare_swap_oom_score_adj(short old_val, short new_val);
> +extern short test_set_oom_score_adj(short new_val);
>
> extern unsigned long oom_badness(struct task_struct *p,
> struct mem_cgroup *memcg, const nodemask_t *nodemask,
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -631,9 +631,9 @@ struct signal_struct {
> struct rw_semaphore group_rwsem;
> #endif
>
> - int oom_score_adj; /* OOM kill score adjustment */
> - int oom_score_adj_min; /* OOM kill score adjustment minimum value.
> - * Only settable by CAP_SYS_RESOURCE. */
> + short oom_score_adj; /* OOM kill score adjustment */
> + short oom_score_adj_min; /* OOM kill score adjustment min value.
> + * Only settable by CAP_SYS_RESOURCE. */
>
> struct mutex cred_guard_mutex; /* guard against foreign influences on
> * credential calculations
> diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h
> --- a/include/trace/events/oom.h
> +++ b/include/trace/events/oom.h
> @@ -14,7 +14,7 @@ TRACE_EVENT(oom_score_adj_update,
> TP_STRUCT__entry(
> __field( pid_t, pid)
> __array( char, comm, TASK_COMM_LEN )
> - __field( int, oom_score_adj)
> + __field( short, oom_score_adj)
> ),
>
> TP_fast_assign(
> @@ -23,7 +23,7 @@ TRACE_EVENT(oom_score_adj_update,
> __entry->oom_score_adj = task->signal->oom_score_adj;
> ),
>
> - TP_printk("pid=%d comm=%s oom_score_adj=%d",
> + TP_printk("pid=%d comm=%s oom_score_adj=%hd",
> __entry->pid, __entry->comm, __entry->oom_score_adj)
> );
>
> diff --git a/include/trace/events/task.h b/include/trace/events/task.h
> --- a/include/trace/events/task.h
> +++ b/include/trace/events/task.h
> @@ -15,7 +15,7 @@ TRACE_EVENT(task_newtask,
> __field( pid_t, pid)
> __array( char, comm, TASK_COMM_LEN)
> __field( unsigned long, clone_flags)
> - __field( int, oom_score_adj)
> + __field( short, oom_score_adj)
> ),
>
> TP_fast_assign(
> @@ -25,7 +25,7 @@ TRACE_EVENT(task_newtask,
> __entry->oom_score_adj = task->signal->oom_score_adj;
> ),
>
> - TP_printk("pid=%d comm=%s clone_flags=%lx oom_score_adj=%d",
> + TP_printk("pid=%d comm=%s clone_flags=%lx oom_score_adj=%hd",
> __entry->pid, __entry->comm,
> __entry->clone_flags, __entry->oom_score_adj)
> );
> @@ -40,7 +40,7 @@ TRACE_EVENT(task_rename,
> __field( pid_t, pid)
> __array( char, oldcomm, TASK_COMM_LEN)
> __array( char, newcomm, TASK_COMM_LEN)
> - __field( int, oom_score_adj)
> + __field( short, oom_score_adj)
> ),
>
> TP_fast_assign(
> @@ -50,7 +50,7 @@ TRACE_EVENT(task_rename,
> __entry->oom_score_adj = task->signal->oom_score_adj;
> ),
>
> - TP_printk("pid=%d oldcomm=%s newcomm=%s oom_score_adj=%d",
> + TP_printk("pid=%d oldcomm=%s newcomm=%s oom_score_adj=%hd",
> __entry->pid, __entry->oldcomm,
> __entry->newcomm, __entry->oom_score_adj)
> );
> diff --git a/mm/ksm.c b/mm/ksm.c
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -1929,7 +1929,7 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
> if (ksm_run != flags) {
> ksm_run = flags;
> if (flags & KSM_RUN_UNMERGE) {
> - int oom_score_adj;
> + short oom_score_adj;
>
> oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
> err = unmerge_and_remove_all_rmap_items();
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -53,7 +53,7 @@ static DEFINE_SPINLOCK(zone_scan_lock);
> * @old_val. Usually used to reinstate a previous value to prevent racing with
> * userspacing tuning the value in the interim.
> */
> -void compare_swap_oom_score_adj(int old_val, int new_val)
> +void compare_swap_oom_score_adj(short old_val, short new_val)
> {
> struct sighand_struct *sighand = current->sighand;
>
> @@ -72,7 +72,7 @@ void compare_swap_oom_score_adj(int old_val, int new_val)
> * synchronization and returns the old value. Usually used to temporarily
> * set a value, save the old value in the caller, and then reinstate it later.
> */
> -int test_set_oom_score_adj(int new_val)
> +short test_set_oom_score_adj(short new_val)
> {
> struct sighand_struct *sighand = current->sighand;
> int old_val;
> @@ -193,7 +193,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
> if (!p)
> return 0;
>
> - adj = p->signal->oom_score_adj;
> + adj = (long)p->signal->oom_score_adj;
> if (adj == OOM_SCORE_ADJ_MIN) {
> task_unlock(p);
> return 0;
> @@ -412,7 +412,7 @@ static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemas
> continue;
> }
>
> - pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu %5d %s\n",
> + pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu %5hd %s\n",
> task->pid, from_kuid(&init_user_ns, task_uid(task)),
> task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
> task->mm->nr_ptes,
> @@ -428,7 +428,7 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
> {
> task_lock(current);
> pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
> - "oom_score_adj=%d\n",
> + "oom_score_adj=%hd\n",
> current->comm, gfp_mask, order,
> current->signal->oom_score_adj);
> cpuset_print_task_mems_allowed(current);
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -1484,7 +1484,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
> struct address_space *mapping;
> struct inode *inode;
> struct filename *pathname;
> - int oom_score_adj;
> + short oom_score_adj;
> int i, type, prev;
> int err;
>
--
Michal Hocko
SUSE Labs
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