On Thu, May 10, 2018 at 05:55:25PM +0000, Matt Macy wrote:
> Author: mmacy
> Date: Thu May 10 17:55:24 2018
> New Revision: 333466
> URL: https://svnweb.freebsd.org/changeset/base/333466
>
> Log:
> Add simple preempt safe epoch API
>
> Read locking is over used in the kernel to guarantee liveness. This API
> makes
> it easy to provide livenes guarantees without atomics.
>
> Includes epoch_test kernel module to stress test the API.
>
> Documentation will follow initial use case.
>
> Test case and improvements to preemption handling in response to discussion
> with mjg@
>
> Reviewed by: imp@, shurd@
> Approved by: sbruno@
>
> Added:
> head/sys/kern/subr_epoch.c (contents, props changed)
> head/sys/modules/epoch_test/
> head/sys/modules/epoch_test/Makefile (contents, props changed)
> head/sys/sys/epoch.h (contents, props changed)
> head/sys/tests/epoch/
> head/sys/tests/epoch/epoch_test.c (contents, props changed)
> Modified:
> head/contrib/bmake/job.c
> head/sys/conf/files
> head/sys/conf/kern.pre.mk
> head/sys/kern/kern_malloc.c
> head/sys/kern/kern_synch.c
> head/sys/kern/subr_trap.c
> head/sys/kern/subr_turnstile.c
> head/sys/sys/proc.h
> head/sys/sys/turnstile.h
>
> Modified: head/sys/sys/proc.h
> ==============================================================================
> --- head/sys/sys/proc.h Thu May 10 17:22:04 2018 (r333465)
> +++ head/sys/sys/proc.h Thu May 10 17:55:24 2018 (r333466)
> @@ -243,6 +243,7 @@ struct thread {
>
> /* Cleared during fork1() */
> #define td_startzero td_flags
> + u_char td_epochnest; /* (k) Private thread epoch nest counter */
It looks like td_epochnest was inteded to be in the zeroed section, but
td_startzero still points to td_flags.
> int td_flags; /* (t) TDF_* flags. */
> int td_inhibitors; /* (t) Why can not run. */
> int td_pflags; /* (k) Private thread (TDP_*) flags. */
> @@ -355,6 +356,7 @@ struct thread {
> int td_lastcpu; /* (t) Last cpu we were on. */
> int td_oncpu; /* (t) Which cpu we are on. */
> void *td_lkpi_task; /* LinuxKPI task struct pointer */
> + TAILQ_ENTRY(thread) td_epochq; /* (t) Epoch queue. */
> };
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
