Date: Thu, 23 Jan 2020 16:24:51 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357050 - head/sys/kern Message-ID: <202001231624.00NGOpXl073784@repo.freebsd.org>
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Author: markj Date: Thu Jan 23 16:24:51 2020 New Revision: 357050 URL: https://svnweb.freebsd.org/changeset/base/357050 Log: Set td_oncpu before dropping the thread lock during a switch. After r355784 we no longer hold a thread's thread lock when switching it out. Preserve the previous synchronization protocol for td_oncpu by setting it together with td_state, before dropping the thread lock during a switch. Reported and tested by: pho Reviewed by: kib Discussed with: jeff Differential Revision: https://reviews.freebsd.org/D23270 Modified: head/sys/kern/sched_ule.c Modified: head/sys/kern/sched_ule.c ============================================================================== --- head/sys/kern/sched_ule.c Thu Jan 23 16:10:38 2020 (r357049) +++ head/sys/kern/sched_ule.c Thu Jan 23 16:24:51 2020 (r357050) @@ -2121,6 +2121,7 @@ sched_switch(struct thread *td, int flags) */ TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); newtd = choosethread(); + newtd->td_oncpu = cpuid; sched_pctcpu_update(td_get_sched(newtd), 0); TDQ_UNLOCK(tdq); @@ -2145,7 +2146,6 @@ sched_switch(struct thread *td, int flags) #endif td->td_oncpu = NOCPU; cpu_switch(td, newtd, mtx); - cpuid = td->td_oncpu = PCPU_GET(cpuid); SDT_PROBE0(sched, , , on__cpu); #ifdef HWPMC_HOOKS @@ -2915,6 +2915,7 @@ sched_throw(struct thread *td) thread_lock_block(td); } newtd = choosethread(); + newtd->td_oncpu = PCPU_GET(cpuid); spinlock_enter(); TDQ_UNLOCK(tdq); KASSERT(curthread->td_md.md_spinlock_count == 1,
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