Commit c96fc2d8 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Linus Torvalds
Browse files

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: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 91c4e8ea

include/linux/oom.h

+3 −6
Original line number Diff line number Diff line
@@ -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);

include/linux/sched.h

+5 −1
Original line number Diff line number Diff line
@@ -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. */

include/linux/types.h

+0 −1
Original line number Diff line number Diff line
@@ -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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