git: c84bb8cd771c - main - rmlock: Micro-optimize read locking
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Date: Fri, 25 Feb 2022 18:56:47 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=c84bb8cd771ce4bed58152e47a32dda470bef23a
commit c84bb8cd771ce4bed58152e47a32dda470bef23a
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-02-25 18:42:51 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-02-25 18:55:24 +0000
rmlock: Micro-optimize read locking
Use get_pcpu() instead of an open-coded pcpu_find(td->td_oncpu). This
eliminates some memory accesses and results in a shorter instruction
sequence. Note that get_pcpu() didn't exist when rmlocks were added.
Reviewed by: jah, mjg
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D34377
---
sys/kern/kern_rmlock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sys/kern/kern_rmlock.c b/sys/kern/kern_rmlock.c
index 08a01fca9827..bbea8041360a 100644
--- a/sys/kern/kern_rmlock.c
+++ b/sys/kern/kern_rmlock.c
@@ -452,7 +452,7 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock)
atomic_interrupt_fence();
- pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
+ pc = get_pcpu();
rm_tracker_add(pc, tracker);
@@ -517,7 +517,7 @@ _rm_runlock(struct rmlock *rm, struct rm_priotracker *tracker)
return;
td->td_critnest++; /* critical_enter(); */
- pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
+ pc = get_pcpu();
rm_tracker_remove(pc, tracker);
td->td_critnest--;
sched_unpin();