signal: make oom_flags a bool
Currently the size of "struct signal_struct"->oom_flags member is
sizeof(unsigned) bytes, but only one flag OOM_FLAG_ORIGIN which is
updated by current thread is defined. We can convert OOM_FLAG_ORIGIN
into a bool, and reuse the saved bytes for updating from the OOM killer
and/or the OOM reaper thread.
By the way, do we care about a race window between run_store() and
swapoff() because it would be theoretically possible that two threads
sharing the "struct signal_struct" concurrently call respective
functions? If we care, we can make oom_flags an atomic_t.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/oom.h b/include/linux/oom.h
index d3f533f..8346952 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -50,24 +50,21 @@
OOM_SCAN_SELECT, /* always select this thread first */
};
-/* Thread is the potential origin of an oom condition; kill first on oom */
-#define OOM_FLAG_ORIGIN ((__force oom_flags_t)0x1)
-
extern struct mutex oom_lock;
static inline void set_current_oom_origin(void)
{
- current->signal->oom_flags |= OOM_FLAG_ORIGIN;
+ current->signal->oom_flag_origin = true;
}
static inline void clear_current_oom_origin(void)
{
- current->signal->oom_flags &= ~OOM_FLAG_ORIGIN;
+ current->signal->oom_flag_origin = false;
}
static inline bool oom_task_origin(const struct task_struct *p)
{
- return !!(p->signal->oom_flags & OOM_FLAG_ORIGIN);
+ return p->signal->oom_flag_origin;
}
extern void mark_oom_victim(struct task_struct *tsk);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2c036de..21c26e7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -794,7 +794,11 @@
struct tty_audit_buf *tty_audit_buf;
#endif
- oom_flags_t oom_flags;
+ /*
+ * Thread is the potential origin of an oom condition; kill first on
+ * oom
+ */
+ bool oom_flag_origin;
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. */
diff --git a/include/linux/types.h b/include/linux/types.h
index 70dd3df..baf7183 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -156,7 +156,6 @@
typedef unsigned __bitwise__ gfp_t;
typedef unsigned __bitwise__ fmode_t;
-typedef unsigned __bitwise__ oom_flags_t;
#ifdef CONFIG_PHYS_ADDR_T_64BIT
typedef u64 phys_addr_t;