linux-kernel - [PATCH v6 8/8] mm: add vmstat counters for tracking PCP drains

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1326040026-7285-9-git-send-email-gilad@benyossef.com>
Date:	Sun,  8 Jan 2012 18:27:06 +0200
From:	Gilad Ben-Yossef <gilad@...yossef.com>
To:	linux-kernel@...r.kernel.org
Cc:	Gilad Ben-Yossef <gilad@...yossef.com>,
	Christoph Lameter <cl@...ux.com>,
	Chris Metcalf <cmetcalf@...era.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Frederic Weisbecker <fweisbec@...il.com>, linux-mm@...ck.org,
	Pekka Enberg <penberg@...nel.org>,
	Matt Mackall <mpm@...enic.com>,
	Sasha Levin <levinsasha928@...il.com>,
	Rik van Riel <riel@...hat.com>,
	Andi Kleen <andi@...stfloor.org>, Mel Gorman <mel@....ul.ie>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Avi Kivity <avi@...hat.com>,
	Michal Nazarewicz <mina86@...a86.org>,
	Kosaki Motohiro <kosaki.motohiro@...il.com>
Subject: [PATCH v6 8/8] mm: add vmstat counters for tracking PCP drains

This patch introduces two new vmstat counters for testing purposes:
pcp_global_drain that counts the number of times a per-cpu pages
global drain was requested and pcp_global_ipi_saved that counts
the number of times the number of CPUs with per-cpu pages in any
zone were less then 1/2 of the number of online CPUs.

The patch purpose is to show the usefulness of only sending an IPI
asking to drain per-cpu pages to CPUs that actually have them
instead of a blind global IPI. It is probably not useful by itself.

Signed-off-by: Gilad Ben-Yossef <gilad@...yossef.com>
CC: Christoph Lameter <cl@...ux.com>
CC: Chris Metcalf <cmetcalf@...era.com>
CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Frederic Weisbecker <fweisbec@...il.com>
CC: linux-mm@...ck.org
CC: Pekka Enberg <penberg@...nel.org>
CC: Matt Mackall <mpm@...enic.com>
CC: Sasha Levin <levinsasha928@...il.com>
CC: Rik van Riel <riel@...hat.com>
CC: Andi Kleen <andi@...stfloor.org>
CC: Mel Gorman <mel@....ul.ie>
CC: Andrew Morton <akpm@...ux-foundation.org>
CC: Alexander Viro <viro@...iv.linux.org.uk>
CC: Avi Kivity <avi@...hat.com>
CC: Michal Nazarewicz <mina86@...a86.org>
CC: Kosaki Motohiro <kosaki.motohiro@...il.com>
---
 include/linux/vm_event_item.h |    1 +
 mm/page_alloc.c               |    5 +++++
 mm/vmstat.c                   |    2 ++
 3 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 03b90cd..3657f6f 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -58,6 +58,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		THP_COLLAPSE_ALLOC_FAILED,
 		THP_SPLIT,
 #endif
+		PCP_GLOBAL_DRAIN, PCP_GLOBAL_IPI_SAVED,
 		NR_VM_EVENT_ITEMS
 };
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index dc97199..8677e3e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1118,6 +1118,11 @@ void drain_all_pages(void)
 				cpumask_clear_cpu(cpu, cpus_with_pcps);
 		}
 	on_each_cpu_mask(cpus_with_pcps, drain_local_pages, NULL, 1);
+
+	count_vm_event(PCP_GLOBAL_DRAIN);
+	if (cpumask_weight(cpus_with_pcps) <
+	   (cpumask_weight(cpu_online_mask) / 2))
+		count_vm_event(PCP_GLOBAL_IPI_SAVED);
 }
 
 #ifdef CONFIG_HIBERNATION
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 8fd603b..daf632c 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -786,6 +786,8 @@ const char * const vmstat_text[] = {
 	"thp_collapse_alloc_failed",
 	"thp_split",
 #endif
+	"pcp_global_drain",
+	"pcp_global_ipi_saved"
 
 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 };
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/