diff options
| author | Anton Vorontsov <anton.vorontsov@linaro.org> | 2012-02-06 20:29:41 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-02-08 16:55:45 -0800 |
| commit | 294b27119f2e20643e71a0c1a1b511320a11e4c3 (patch) | |
| tree | 279578d0c662a51f461c087afcc5e6aca8142d6d /drivers/staging/android/lowmemorykiller.c | |
| parent | 350a1955957d73352c043d0f948e3f28bb118c57 (diff) | |
staging: android/lowmemorykiller: Don't grab tasklist_lock
Grabbing tasklist_lock has its disadvantages, i.e. it blocks
process creation and destruction. If there are lots of processes,
blocking doesn't sound as a great idea.
For LMK, it is sufficient to surround tasks list traverse with
rcu_read_{,un}lock().
>From now on using force_sig() is not safe, as it can race with an
already exiting task, so we use send_sig() now. As a downside, it
won't kill PID namespace init processes, but that's not what we
want anyway.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/android/lowmemorykiller.c')
| -rw-r--r-- | drivers/staging/android/lowmemorykiller.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c index 2d8d2b796101..63da8447218f 100644 --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -34,6 +34,7 @@ #include <linux/mm.h> #include <linux/oom.h> #include <linux/sched.h> +#include <linux/rcupdate.h> #include <linux/profile.h> #include <linux/notifier.h> @@ -132,7 +133,7 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) } selected_oom_adj = min_adj; - read_lock(&tasklist_lock); + rcu_read_lock(); for_each_process(p) { struct mm_struct *mm; struct signal_struct *sig; @@ -180,12 +181,12 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) lowmem_deathpending = selected; task_handoff_register(&task_nb); #endif - force_sig(SIGKILL, selected); + send_sig(SIGKILL, selected, 0); rem -= selected_tasksize; } lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n", sc->nr_to_scan, sc->gfp_mask, rem); - read_unlock(&tasklist_lock); + rcu_read_unlock(); return rem; } |