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authorOleg Nesterov <oleg@redhat.com>2014-01-23 15:55:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 16:37:01 -0800
commit74e37200de8e9c4e09b70c21c3f13c2071e77457 (patch)
treede7db4aa1113562665ba7f72d92ef33be788f7b7 /fs
parent942be3875a1931c379bbc37053829dd6847e0f3f (diff)
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@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/array.c15
1 files changed, 3 insertions, 12 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 1bd2077187fd..554a0b229ac2 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -140,24 +140,15 @@ static const char * const task_state_array[] = {
"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,

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