git: 0782a20dc550 - stable/12 - rmlock: Micro-optimize read locking

[Mark Johnston]

The branch stable/12 has been updated by markj:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=0782a20dc550a4b05385017eb2728fb92192124b

commit 0782a20dc550a4b05385017eb2728fb92192124b
Author:     Mark Johnston <ma...@freebsd.org>
AuthorDate: 2022-02-25 18:42:51 +0000
Commit:     Mark Johnston <ma...@freebsd.org>
CommitDate: 2022-03-04 16:32:41 +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
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit c84bb8cd771ce4bed58152e47a32dda470bef23a)
---
 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 585ccce6d2a4..45290ac5d562 100644
--- a/sys/kern/kern_rmlock.c
+++ b/sys/kern/kern_rmlock.c
@@ -451,7 +451,7 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker 
*tracker, int trylock)
 
        __compiler_membar();
 
-       pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
+       pc = get_pcpu();
 
        rm_tracker_add(pc, tracker);
 
@@ -516,7 +516,7 @@ _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();