[patch 1/2] mm, oom: change type of oom_score_adj to short

From: David Rientjes
Date: Thu Nov 08 2012 - 04:26:52 EST


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@xxxxxxxxxx>
---
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;

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