* [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd
@ 2017-08-09 5:51 tsutomu.owa
2017-08-09 16:18 ` David Teigland
0 siblings, 1 reply; 4+ messages in thread
From: tsutomu.owa @ 2017-08-09 5:51 UTC (permalink / raw)
To: cluster-devel.redhat.com
When dlm_recoverd_stop() is called between kthread_should_stop() and
set_task_state(), dlm_recoverd will not wake up.
Signed-off-by: Tadashi Miyauchi <miyauchi@toshiba-tops.co.jp>
Signed-off-by: Tsutomu Owa <tsutomu.owa@toshiba.co.jp>
---
fs/dlm/recoverd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 6859b4b..d3956cc 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -276,6 +276,7 @@ static void do_ls_recovery(struct dlm_ls *ls)
static int dlm_recoverd(void *arg)
{
struct dlm_ls *ls;
+ unsigned long timeout = (dlm_config.ci_recover_timer * HZ) >> 1;
ls = dlm_find_lockspace_local(arg);
if (!ls) {
@@ -291,7 +292,7 @@ static int dlm_recoverd(void *arg)
set_current_state(TASK_INTERRUPTIBLE);
if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
!test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
- schedule();
+ schedule_timeout(timeout);
set_current_state(TASK_RUNNING);
if (test_and_clear_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd
2017-08-09 5:51 [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd tsutomu.owa
@ 2017-08-09 16:18 ` David Teigland
2017-08-17 23:40 ` tsutomu.owa
0 siblings, 1 reply; 4+ messages in thread
From: David Teigland @ 2017-08-09 16:18 UTC (permalink / raw)
To: cluster-devel.redhat.com
On Wed, Aug 09, 2017 at 05:51:01AM +0000, tsutomu.owa at toshiba.co.jp wrote:
> When dlm_recoverd_stop() is called between kthread_should_stop() and
> set_task_state(), dlm_recoverd will not wake up.
This works, but have you looked elsewhere in the kernel for kthread
examples we could copy that do a race-free check without a timeout?
Thanks
>
> Signed-off-by: Tadashi Miyauchi <miyauchi@toshiba-tops.co.jp>
> Signed-off-by: Tsutomu Owa <tsutomu.owa@toshiba.co.jp>
> ---
> fs/dlm/recoverd.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
> index 6859b4b..d3956cc 100644
> --- a/fs/dlm/recoverd.c
> +++ b/fs/dlm/recoverd.c
> @@ -276,6 +276,7 @@ static void do_ls_recovery(struct dlm_ls *ls)
> static int dlm_recoverd(void *arg)
> {
> struct dlm_ls *ls;
> + unsigned long timeout = (dlm_config.ci_recover_timer * HZ) >> 1;
>
> ls = dlm_find_lockspace_local(arg);
> if (!ls) {
> @@ -291,7 +292,7 @@ static int dlm_recoverd(void *arg)
> set_current_state(TASK_INTERRUPTIBLE);
> if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
> !test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
> - schedule();
> + schedule_timeout(timeout);
> set_current_state(TASK_RUNNING);
>
> if (test_and_clear_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
> --
> 2.7.4
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd
2017-08-09 16:18 ` David Teigland
@ 2017-08-17 23:40 ` tsutomu.owa
2017-08-22 18:21 ` David Teigland
0 siblings, 1 reply; 4+ messages in thread
From: tsutomu.owa @ 2017-08-17 23:40 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
> This works, but have you looked elsewhere in the kernel for kthread
> examples we could copy that do a race-free check without a timeout?
If you refer to other implementations in kernel, the following
modifications may be better.
The important thing is to call kthread_should_stop() after
set_current_state(TASK_INTERRUPTIBLE). How is this fix?
--- fs/dlm/recoverd.c.orig 2017-08-10 16:42:31.131296351 +0900
+++ fs/dlm/recoverd.c 2017-08-10 16:43:22.483295232 +0900
@@ -287,8 +287,10 @@
set_bit(LSFL_RECOVER_LOCK, &ls->ls_flags);
wake_up(&ls->ls_recover_lock_wait);
- while (!kthread_should_stop()) {
+ while (1) {
set_current_state(TASK_INTERRUPTIBLE);
+ if (kthread_should_stop())
+ break;
if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
!test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
schedule();
thanks,
-- owa
-----Original Message-----
From: David Teigland [mailto:teigland at redhat.com]
Sent: Thursday, August 10, 2017 1:19 AM
To: owa tsutomu(?? ? ??? ?????????????)
Cc: cluster-devel at redhat.com; miyauchi tadashi(?? ?? ???? ?????????)
Subject: Re: [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd
On Wed, Aug 09, 2017 at 05:51:01AM +0000, tsutomu.owa at toshiba.co.jp wrote:
> When dlm_recoverd_stop() is called between kthread_should_stop() and
> set_task_state(), dlm_recoverd will not wake up.
This works, but have you looked elsewhere in the kernel for kthread
examples we could copy that do a race-free check without a timeout?
Thanks
>
> Signed-off-by: Tadashi Miyauchi <miyauchi@toshiba-tops.co.jp>
> Signed-off-by: Tsutomu Owa <tsutomu.owa@toshiba.co.jp>
> ---
> fs/dlm/recoverd.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
> index 6859b4b..d3956cc 100644
> --- a/fs/dlm/recoverd.c
> +++ b/fs/dlm/recoverd.c
> @@ -276,6 +276,7 @@ static void do_ls_recovery(struct dlm_ls *ls)
> static int dlm_recoverd(void *arg)
> {
> struct dlm_ls *ls;
> + unsigned long timeout = (dlm_config.ci_recover_timer * HZ) >> 1;
>
> ls = dlm_find_lockspace_local(arg);
> if (!ls) {
> @@ -291,7 +292,7 @@ static int dlm_recoverd(void *arg)
> set_current_state(TASK_INTERRUPTIBLE);
> if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
> !test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
> - schedule();
> + schedule_timeout(timeout);
> set_current_state(TASK_RUNNING);
>
> if (test_and_clear_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
> --
> 2.7.4
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd
2017-08-17 23:40 ` tsutomu.owa
@ 2017-08-22 18:21 ` David Teigland
0 siblings, 0 replies; 4+ messages in thread
From: David Teigland @ 2017-08-22 18:21 UTC (permalink / raw)
To: cluster-devel.redhat.com
On Thu, Aug 17, 2017 at 11:40:13PM +0000, tsutomu.owa at toshiba.co.jp wrote:
> If you refer to other implementations in kernel, the following
> modifications may be better.
> The important thing is to call kthread_should_stop() after
> set_current_state(TASK_INTERRUPTIBLE). How is this fix?
Thanks, I prefer this. Perhaps put that explanation in a comment, e.g.
> --- fs/dlm/recoverd.c.orig 2017-08-10 16:42:31.131296351 +0900
> +++ fs/dlm/recoverd.c 2017-08-10 16:43:22.483295232 +0900
> @@ -287,8 +287,10 @@
> set_bit(LSFL_RECOVER_LOCK, &ls->ls_flags);
> wake_up(&ls->ls_recover_lock_wait);
>
> - while (!kthread_should_stop()) {
> + while (1) {
/* call kthread_should_stop() after set_current_state() /
> set_current_state(TASK_INTERRUPTIBLE);
> + if (kthread_should_stop())
> + break;
> if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
> !test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
> schedule();
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-08-09 5:51 [Cluster-devel] [PATCH 10/17] dlm: use schedule_timeout instead of schedule in dlm_recoverd tsutomu.owa
2017-08-09 16:18 ` David Teigland
2017-08-17 23:40 ` tsutomu.owa
2017-08-22 18:21 ` David Teigland
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