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/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. */
