From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/oom.h | 9 +++------
include/linux/sched.h | 6 +++++-
include/linux/types.h | 1 -
3 files changed, 8 insertions(+), 8 deletions(-)
diff -puN include/linux/oom.h~signal-make-oom_flags-a-bool include/linux/oom.h
--- a/include/linux/oom.h~signal-make-oom_flags-a-bool
+++ a/include/linux/oom.h
@@ -50,24 +50,21 @@ enum oom_scan_t {
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 -puN include/linux/sched.h~signal-make-oom_flags-a-bool include/linux/sched.h
--- a/include/linux/sched.h~signal-make-oom_flags-a-bool
+++ a/include/linux/sched.h
@@ -794,7 +794,11 @@ struct signal_struct {
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 -puN include/linux/types.h~signal-make-oom_flags-a-bool include/linux/types.h
--- a/include/linux/types.h~signal-make-oom_flags-a-bool
+++ a/include/linux/types.h
@@ -156,7 +156,6 @@ typedef u32 dma_addr_t;
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;
_
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