svn commit: r336149 - in head/sys: kern vm
Mark Johnston
markj at FreeBSD.org
Tue Jul 10 00:18:14 UTC 2018
Author: markj
Date: Tue Jul 10 00:18:12 2018
New Revision: 336149
URL: https://svnweb.freebsd.org/changeset/base/336149
Log:
Fix pre-SI_SUB_CPU initialization of per-CPU counters.
r336020 introduced pcpu_page_alloc(), replacing page_alloc() as the
backend allocator for PCPU UMA zones. Unlike page_alloc(), it does
not honour malloc(9) flags such as M_ZERO or M_NODUMP, so fix that.
r336020 also changed counter(9) to initialize each counter using a
CPU_FOREACH() loop instead of an SMP rendezvous. Before SI_SUB_CPU,
smp_rendezvous() will only execute the callback on the current CPU
(i.e., CPU 0), so only one counter gets zeroed. The rest are zeroed
by virtue of the fact that UMA gratuitously zeroes slabs when importing
them into a zone.
Prior to SI_SUB_CPU, all_cpus is clear, so with r336020 we weren't
zeroing vm_cnt counters during boot: the CPU_FOREACH() loop had no
effect, and pcpu_page_alloc() didn't honour M_ZERO. Fix this by
iterating over the full range of CPU IDs when zeroing counters,
ignoring whether the corresponding bits in all_cpus are set.
Reported and tested by: pho (previous version)
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D16190
Modified:
head/sys/kern/subr_counter.c
head/sys/vm/uma_core.c
Modified: head/sys/kern/subr_counter.c
==============================================================================
--- head/sys/kern/subr_counter.c Tue Jul 10 00:01:14 2018 (r336148)
+++ head/sys/kern/subr_counter.c Tue Jul 10 00:18:12 2018 (r336149)
@@ -43,15 +43,6 @@ __FBSDID("$FreeBSD$");
#define IN_SUBR_COUNTER_C
#include <sys/counter.h>
-static void
-counter_u64_zero_sync(counter_u64_t c)
-{
- int cpu;
-
- CPU_FOREACH(cpu)
- *(uint64_t*)zpcpu_get_cpu(c, cpu) = 0;
-}
-
void
counter_u64_zero(counter_u64_t c)
{
@@ -69,13 +60,8 @@ counter_u64_fetch(counter_u64_t c)
counter_u64_t
counter_u64_alloc(int flags)
{
- counter_u64_t r;
- r = uma_zalloc_pcpu(pcpu_zone_64, flags);
- if (r != NULL)
- counter_u64_zero_sync(r);
-
- return (r);
+ return (uma_zalloc_pcpu(pcpu_zone_64, flags | M_ZERO));
}
void
Modified: head/sys/vm/uma_core.c
==============================================================================
--- head/sys/vm/uma_core.c Tue Jul 10 00:01:14 2018 (r336148)
+++ head/sys/vm/uma_core.c Tue Jul 10 00:18:12 2018 (r336149)
@@ -1186,13 +1186,12 @@ pcpu_page_alloc(uma_zone_t zone, vm_size_t bytes, int
struct pcpu *pc;
#endif
- TAILQ_INIT(&alloctail);
- MPASS(bytes == (mp_maxid+1)*PAGE_SIZE);
- *pflag = UMA_SLAB_KERNEL;
+ MPASS(bytes == (mp_maxid + 1) * PAGE_SIZE);
+ TAILQ_INIT(&alloctail);
flags = VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | VM_ALLOC_NOOBJ |
- ((wait & M_WAITOK) != 0 ? VM_ALLOC_WAITOK :
- VM_ALLOC_NOWAIT);
+ malloc2vm_flags(wait);
+ *pflag = UMA_SLAB_KERNEL;
for (cpu = 0; cpu <= mp_maxid; cpu++) {
if (CPU_ABSENT(cpu)) {
p = vm_page_alloc(NULL, 0, flags);
@@ -2328,10 +2327,10 @@ uma_zalloc_pcpu_arg(uma_zone_t zone, void *udata, int
MPASS(zone->uz_flags & UMA_ZONE_PCPU);
#endif
- item = uma_zalloc_arg(zone, udata, flags &~ M_ZERO);
+ item = uma_zalloc_arg(zone, udata, flags & ~M_ZERO);
if (item != NULL && (flags & M_ZERO)) {
#ifdef SMP
- CPU_FOREACH(i)
+ for (i = 0; i <= mp_maxid; i++)
bzero(zpcpu_get_cpu(item, i), zone->uz_size);
#else
bzero(item, zone->uz_size);
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