Module Name: src
Committed By: riastradh
Date: Thu Mar 10 12:21:35 UTC 2022
Modified Files:
src/sys/kern: kern_proc.c
Log Message:
kern: Use atomic_store_release/atomic_load_consume for pid_table.
This is read without the lock, so ordering is required.
To generate a diff of this commit:
cvs rdiff -u -r1.263 -r1.264 src/sys/kern/kern_proc.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_proc.c
diff -u src/sys/kern/kern_proc.c:1.263 src/sys/kern/kern_proc.c:1.264
--- src/sys/kern/kern_proc.c:1.263 Sat Feb 12 15:51:29 2022
+++ src/sys/kern/kern_proc.c Thu Mar 10 12:21:35 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_proc.c,v 1.263 2022/02/12 15:51:29 thorpej Exp $ */
+/* $NetBSD: kern_proc.c,v 1.264 2022/03/10 12:21:35 riastradh Exp $ */
/*-
* Copyright (c) 1999, 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.263 2022/02/12 15:51:29 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.264 2022/03/10 12:21:35 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_kstack.h"
@@ -695,7 +695,7 @@ proc_find_lwp(proc_t *p, pid_t pid)
* memory barrier for dependent loads on alpha.
*/
s = pserialize_read_enter();
- pt = &pid_table[pid & pid_tbl_mask];
+ pt = &atomic_load_consume(&pid_table)[pid & pid_tbl_mask];
slot = atomic_load_consume(&pt->pt_slot);
if (__predict_false(!PT_IS_LWP(slot))) {
pserialize_read_exit(s);
@@ -753,7 +753,7 @@ proc_find_lwp_unlocked(proc_t *p, pid_t
* care to read the slot atomically and only once. This issues a
* memory barrier for dependent loads on alpha.
*/
- pt = &pid_table[pid & pid_tbl_mask];
+ pt = &atomic_load_consume(&pid_table)[pid & pid_tbl_mask];
slot = atomic_load_consume(&pt->pt_slot);
if (__predict_false(!PT_IS_LWP(slot))) {
return NULL;
@@ -1003,7 +1003,7 @@ expand_pid_table(void)
/* Save old table size and switch tables */
tsz = pt_size * sizeof(struct pid_table);
n_pt = pid_table;
- pid_table = new_pt;
+ atomic_store_release(&pid_table, new_pt);
pid_tbl_mask = new_pt_mask;
/*
