Subject: + proc-cleanup-simplify-get_task_state-task_state_array.patch added to -mm tree
To: oleg@xxxxxxxxxx,David.Laight@xxxxxxxxxx,geert@xxxxxxxxxxxxxx,mingo@xxxxxxxxxx,peterz@xxxxxxxxxxxxx,tj@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 20 Nov 2013 14:03:53 -0800
The patch titled
Subject: proc: cleanup/simplify get_task_state/task_state_array
has been added to the -mm tree. Its filename is
proc-cleanup-simplify-get_task_state-task_state_array.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-cleanup-simplify-get_task_state-task_state_array.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-cleanup-simplify-get_task_state-task_state_array.patch
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From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: proc: cleanup/simplify get_task_state/task_state_array
get_task_state() and task_state_array[] look confusing and suboptimal, it
is not clear what it can actually report to user-space and
task_state_array[] blows .data for no reason.
1. state = (tsk->state & TASK_REPORT) | tsk->exit_state is not
clear. TASK_REPORT is self-documenting but it is not clear
what ->exit_state can add.
Move the potential exit_state's (EXIT_ZOMBIE and EXIT_DEAD)
into TASK_REPORT and use it to calculate the final result.
2. With the change above it is obvious that task_state_array[]
has the unused entries just to make BUILD_BUG_ON() happy.
Change this BUILD_BUG_ON() to use TASK_REPORT rather than
TASK_STATE_MAX and shrink task_state_array[].
3. Turn the "while (state)" loop into fls(state).
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/array.c | 15 +++------------
include/linux/sched.h | 2 +-
2 files changed, 4 insertions(+), 13 deletions(-)
diff -puN fs/proc/array.c~proc-cleanup-simplify-get_task_state-task_state_array fs/proc/array.c
--- a/fs/proc/array.c~proc-cleanup-simplify-get_task_state-task_state_array
+++ a/fs/proc/array.c
@@ -140,24 +140,15 @@ static const char * const task_state_arr
"t (tracing stop)", /* 8 */
"Z (zombie)", /* 16 */
"X (dead)", /* 32 */
- "x (dead)", /* 64 */
- "K (wakekill)", /* 128 */
- "W (waking)", /* 256 */
- "P (parked)", /* 512 */
};
static inline const char *get_task_state(struct task_struct *tsk)
{
- unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state;
- const char * const *p = &task_state_array[0];
+ unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
- BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array));
+ BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
- while (state) {
- p++;
- state >>= 1;
- }
- return *p;
+ return task_state_array[fls(state)];
}
static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
diff -puN include/linux/sched.h~proc-cleanup-simplify-get_task_state-task_state_array include/linux/sched.h
--- a/include/linux/sched.h~proc-cleanup-simplify-get_task_state-task_state_array
+++ a/include/linux/sched.h
@@ -164,7 +164,7 @@ extern char ___assert_task_state[1 - 2*!
/* get_task_state() */
#define TASK_REPORT (TASK_RUNNING | TASK_INTERRUPTIBLE | \
TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
- __TASK_TRACED)
+ __TASK_TRACED | EXIT_ZOMBIE | EXIT_DEAD)
#define task_is_traced(task) ((task->state & __TASK_TRACED) != 0)
#define task_is_stopped(task) ((task->state & __TASK_STOPPED) != 0)
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
coredump-set_dumpable-fix-the-theoretical-race-with-itself.patch
coredump-kill-mmf_dumpable-and-mmf_dump_securely.patch
coredump-make-__get_dumpable-get_dumpable-inline-kill-fs-coredumph.patch
linux-next.patch
proc-cleanup-simplify-get_task_state-task_state_array.patch
fork-no-need-to-initialize-child-exit_state.patch
exit_state-kill-task_is_dead.patch
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