2019-04-30 22:19:32

by Prarit Bhargava

Subject: [PATCH v2] kernel/module: Reschedule while waiting for modules to finish loading

On a s390 z14 LAR with 2 cpus about stalls about 3% of the time while
loading the s390_trng.ko module.

Add a reschedule point to the loop that waits for modules to complete
loading.

v2: cleanup Fixes line.

Reported-by: Heiko Carstens <[email protected]>
Fixes: commit f9a75c1d717f ("modules: Only return -EEXIST for modules that have finished loading")
Signed-off-by: Prarit Bhargava <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Heiko Carstens <[email protected]>
---
kernel/module.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/module.c b/kernel/module.c
index 410eeb7e4f1d..48748cfec991 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3585,6 +3585,7 @@ static int add_unformed_module(struct module *mod)
finished_loading(mod->name));
if (err)
goto out_unlocked;
+ cond_resched();
goto again;
}
err = -EEXIST;
--
2.18.1

2019-04-30 22:23:27

by Prarit Bhargava

Subject: Re: [PATCH v2] kernel/module: Reschedule while waiting for modules to finish loading

On 4/30/19 6:18 PM, Prarit Bhargava wrote:
> On a s390 z14 LAR with 2 cpus about stalls about 3% of the time while
> loading the s390_trng.ko module.
>
> Add a reschedule point to the loop that waits for modules to complete
> loading.
>

Sorry, sent in error.

P.

> v2: cleanup Fixes line.
>
> Reported-by: Heiko Carstens <[email protected]>
> Fixes: commit f9a75c1d717f ("modules: Only return -EEXIST for modules that have finished loading")
> Signed-off-by: Prarit Bhargava <[email protected]>
> Cc: Jessica Yu <[email protected]>
> Cc: Heiko Carstens <[email protected]>
> ---
> kernel/module.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 410eeb7e4f1d..48748cfec991 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3585,6 +3585,7 @@ static int add_unformed_module(struct module *mod)
> finished_loading(mod->name));
> if (err)
> goto out_unlocked;
> + cond_resched();
> goto again;
> }
> err = -EEXIST;
>