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Set td_oncpu before dropping the thread lock during a switch.

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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
This commit is contained in:
Mark Johnston 2020-01-23 16:24:51 +00:00
parent b6cf94ae07
commit 1bfca40c57
1 changed files with 2 additions and 1 deletions
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3
sys/kern/sched_ule.c
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@ -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,