linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Marcelo Tosatti <mtosatti@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Russell King <linux@armlinux.org.uk>,
	Huacai Chen <chenhuacai@kernel.org>,
	Heiko Carstens <hca@linux.ibm.com>,
	x86@kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	Michal Hocko <mhocko@suse.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: [PATCH v8 10/13] mm/vmstat: use xchg in cpu_vm_stats_fold
Date: Mon, 15 May 2023 15:00:25 -0300	[thread overview]
Message-ID: <20230515180138.668066640@redhat.com> (raw)
In-Reply-To: <20230515180015.016409657@redhat.com>

In preparation to switch vmstat shepherd to flush
per-CPU counters remotely, use xchg instead of a
pair of read/write instructions.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---

Index: linux-vmstat-remote/mm/vmstat.c
===================================================================
--- linux-vmstat-remote.orig/mm/vmstat.c
+++ linux-vmstat-remote/mm/vmstat.c
@@ -924,7 +924,7 @@ static int refresh_cpu_vm_stats(bool do_
 }
 
 /*
- * Fold the data for an offline cpu into the global array.
+ * Fold the data for a cpu into the global array.
  * There cannot be any access by the offline cpu and therefore
  * synchronization is simplified.
  */
@@ -945,8 +945,7 @@ void cpu_vm_stats_fold(int cpu)
 			if (pzstats->vm_stat_diff[i]) {
 				int v;
 
-				v = pzstats->vm_stat_diff[i];
-				pzstats->vm_stat_diff[i] = 0;
+				v = xchg(&pzstats->vm_stat_diff[i], 0);
 				atomic_long_add(v, &zone->vm_stat[i]);
 				global_zone_diff[i] += v;
 			}
@@ -956,8 +955,7 @@ void cpu_vm_stats_fold(int cpu)
 			if (pzstats->vm_numa_event[i]) {
 				unsigned long v;
 
-				v = pzstats->vm_numa_event[i];
-				pzstats->vm_numa_event[i] = 0;
+				v = xchg(&pzstats->vm_numa_event[i], 0);
 				zone_numa_event_add(v, zone, i);
 			}
 		}
@@ -973,8 +971,7 @@ void cpu_vm_stats_fold(int cpu)
 			if (p->vm_node_stat_diff[i]) {
 				int v;
 
-				v = p->vm_node_stat_diff[i];
-				p->vm_node_stat_diff[i] = 0;
+				v = xchg(&p->vm_node_stat_diff[i], 0);
 				atomic_long_add(v, &pgdat->vm_stat[i]);
 				global_node_diff[i] += v;
 			}




  parent reply	other threads:[~2023-05-15 18:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-15 18:00 [PATCH v8 00/13] fold per-CPU vmstats remotely Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 01/13] vmstat: allow_direct_reclaim should use zone_page_state_snapshot Marcelo Tosatti
2023-05-24 12:34   ` Michal Hocko
2023-05-25  7:05   ` Aaron Tomlin
2023-05-15 18:00 ` [PATCH v8 02/13] this_cpu_cmpxchg: ARM64: switch this_cpu_cmpxchg to locked, add _local function Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 03/13] this_cpu_cmpxchg: loongarch: " Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 04/13] this_cpu_cmpxchg: S390: " Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 05/13] this_cpu_cmpxchg: x86: " Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 06/13] add this_cpu_cmpxchg_local and asm-generic definitions Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 07/13] convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 08/13] mm/vmstat: switch counter modification to cmpxchg Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 09/13] vmstat: switch per-cpu vmstat counters to 32-bits Marcelo Tosatti
2023-05-15 18:00 ` Marcelo Tosatti [this message]
2023-05-15 18:00 ` [PATCH v8 11/13] mm/vmstat: switch vmstat shepherd to flush per-CPU counters remotely Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 12/13] mm/vmstat: refresh stats remotely instead of via work item Marcelo Tosatti
2023-05-15 18:00 ` [PATCH v8 13/13] vmstat: add pcp remote node draining via cpu_vm_stats_fold Marcelo Tosatti
2023-05-16  8:09 ` [PATCH v8 00/13] fold per-CPU vmstats remotely Christoph Lameter
2023-05-16 18:02   ` Marcelo Tosatti
2023-05-24 12:51 ` Michal Hocko
2023-05-24 13:53   ` Marcelo Tosatti
2023-05-25  6:47     ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230515180138.668066640@redhat.com \
    --to=mtosatti@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=atomlin@atomlin.com \
    --cc=chenhuacai@kernel.org \
    --cc=cl@linux.com \
    --cc=frederic@kernel.org \
    --cc=hca@linux.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux@armlinux.org.uk \
    --cc=mhocko@suse.com \
    --cc=vbabka@suse.cz \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox