linux-kernel - [PATCH v4 5/5] mm: Only IPI CPUs to drain local pages if they exist

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

Message-Id: <1321960128-15191-6-git-send-email-gilad@benyossef.com>
Date:	Tue, 22 Nov 2011 13:08:48 +0200
From:	Gilad Ben-Yossef <gilad@...yossef.com>
To:	linux-kernel@...r.kernel.org
Cc:	Gilad Ben-Yossef <gilad@...yossef.com>,
	Chris Metcalf <cmetcalf@...era.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Russell King <linux@....linux.org.uk>, 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>
Subject: [PATCH v4 5/5] mm: Only IPI CPUs to drain local pages if they exist

Calculate a cpumask of CPUs with per-cpu pages in any zone and only send an IPI requesting CPUs to drain these pages to the buddy allocator if they actually have pages when asked to flush.

The code path of memory allocation failure for CPUMASK_OFFSTACK=y config was tested using fault injection framework.

Signed-off-by: Gilad Ben-Yossef <gilad@...yossef.com>
Acked-by: 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: Russell King <linux@....linux.org.uk>
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>
---
 mm/page_alloc.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9dd443d..a3efdf1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1119,7 +1119,23 @@ void drain_local_pages(void *arg)
  */
 void drain_all_pages(void)
 {
-	on_each_cpu(drain_local_pages, NULL, 1);
+	int cpu;
+	struct zone *zone;
+	cpumask_var_t cpus;
+	struct per_cpu_pageset *pcp;
+
+	if (likely(zalloc_cpumask_var(&cpus, GFP_ATOMIC))) {
+		for_each_online_cpu(cpu) {
+			for_each_populated_zone(zone) {
+				pcp = per_cpu_ptr(zone->pageset, cpu);
+				if (pcp->pcp.count)
+					cpumask_set_cpu(cpu, cpus);
+		}
+	}
+		on_each_cpu_mask(cpus, drain_local_pages, NULL, 1);
+		free_cpumask_var(cpus);
+	} else
+		on_each_cpu(drain_local_pages, NULL, 1);
 }
 
 #ifdef CONFIG_HIBERNATION
-- 
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/