svn commit: r326376 - head/sys/kern
Cy Schubert
Cy.Schubert at komquats.com
Thu Nov 30 03:02:47 UTC 2017
In message <201711292328.vATNSeOM046518 at repo.freebsd.org>, Hans Petter
Selasky
writes:
> Author: hselasky
> Date: Wed Nov 29 23:28:40 2017
> New Revision: 326376
> URL: https://svnweb.freebsd.org/changeset/base/326376
>
> Log:
> The sched_add() function is not only used when the thread is initially
> started, but also by the turnstiles to mark a thread as runnable for
> all locks, for instance sleepqueues do:
> setrunnable()->sched_wakeup()->sched_add()
>
> In r326218 code was added to allow booting from non-zero CPU numbers
> by setting the ts_cpu field inside the ULE scheduler's sched_add()
> function. This had an undesired side-effect that prior sched_pin() and
> sched_bind() calls got disregarded. This patch fixes the
> initialization of the ts_cpu field for the ULE scheduler to only
> happen once when the initial thread is constructed during system
> init. Forking will then later on ensure that a valid ts_cpu value gets
> copied to all children.
>
> Reviewed by: jhb, kib
> Discussed with: nwhitehorn
> MFC after: 1 month
> Differential revision: https://reviews.freebsd.org/D13298
> Sponsored by: Mellanox Technologies
>
> Modified:
> head/sys/kern/sched_ule.c
>
> Modified: head/sys/kern/sched_ule.c
> =============================================================================
> =
> --- head/sys/kern/sched_ule.c Wed Nov 29 21:16:14 2017 (r326375)
> +++ head/sys/kern/sched_ule.c Wed Nov 29 23:28:40 2017 (r326376)
> @@ -1405,7 +1405,6 @@ sched_setup(void *dummy)
>
> /* Add thread0's load since it's running. */
> TDQ_LOCK(tdq);
> - td_get_sched(&thread0)->ts_cpu = curcpu; /* Something valid to start */
> thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
> tdq_load_add(tdq, &thread0);
> tdq->tdq_lowpri = thread0.td_priority;
> @@ -1642,6 +1641,7 @@ schedinit(void)
> ts0->ts_ltick = ticks;
> ts0->ts_ftick = ticks;
> ts0->ts_slice = 0;
> + ts0->ts_cpu = curcpu; /* set valid CPU number */
> }
>
> /*
> @@ -2453,7 +2453,6 @@ sched_add(struct thread *td, int flags)
> * Pick the destination cpu and if it isn't ours transfer to the
> * target cpu.
> */
> - td_get_sched(td)->ts_cpu = curcpu; /* Pick something valid to start */
> cpu = sched_pickcpu(td, flags);
> tdq = sched_setcpu(td, cpu, flags);
> tdq_add(tdq, td, flags);
>
Thank you.
--
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX: <cy at FreeBSD.org> Web: http://www.FreeBSD.org
The need of the many outweighs the greed of the few.
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