2020-04-22 11:34:09

by Peter Zijlstra

Subject: [PATCH 03/23] sched,crypto: Convert to sched_set_fifo*()

Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

Use sched_set_fifo() to request SCHED_FIFO and delegate
actual priority selection to userspace. Effectively no change in
behaviour.

Cc: [email protected]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Ingo Molnar <[email protected]>
---
crypto/crypto_engine.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/crypto/crypto_engine.c
+++ b/crypto/crypto_engine.c
@@ -396,7 +396,6 @@ EXPORT_SYMBOL_GPL(crypto_engine_stop);
*/
struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
{
- struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
struct crypto_engine *engine;

if (!dev)
@@ -428,7 +427,7 @@ struct crypto_engine *crypto_engine_allo

if (engine->rt) {
dev_info(dev, "will run requests pump with realtime priority\n");
- sched_setscheduler(engine->kworker->task, SCHED_FIFO, &param);
+ sched_set_fifo(engine->kworker->task);
}

return engine;

2020-04-22 14:39:57

by Herbert Xu

Subject: Re: [PATCH 03/23] sched,crypto: Convert to sched_set_fifo*()

On Wed, Apr 22, 2020 at 01:27:22PM +0200, Peter Zijlstra wrote:
> Because SCHED_FIFO is a broken scheduler model (see previous patches)
> take away the priority field, the kernel can't possibly make an
> informed decision.
>
> Use sched_set_fifo() to request SCHED_FIFO and delegate
> actual priority selection to userspace. Effectively no change in
> behaviour.
>
> Cc: [email protected]
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> Reviewed-by: Ingo Molnar <[email protected]>
> ---
> crypto/crypto_engine.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

Acked-by: Herbert Xu <[email protected]>
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt