Date: Fri, 11 May 2018 11:59:32 -0700 From: Matthew Macy <mmacy@freebsd.org> To: Mark Johnston <markj@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r333466 - in head: contrib/bmake sys/conf sys/kern sys/modules/epoch_test sys/sys sys/tests/epoch Message-ID: <CAPrugNpvhf%2BfhtE0rbv28Rsr1L_LiKrU6mfjFBXWBH5uAKdhHA@mail.gmail.com> In-Reply-To: <20180511184735.GA34339@raichu> References: <201805101755.w4AHtPRt028900@repo.freebsd.org> <20180511184735.GA34339@raichu>
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Thanks On Fri, May 11, 2018 at 11:47 Mark Johnston <markj@freebsd.org> wrote: > 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. */ > > }; >
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