linux-kernel - [PATCH 12/15] sched: Remove check that skips small VMAs

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <1373065742-9753-13-git-send-email-mgorman@suse.de>
Date:	Sat,  6 Jul 2013 00:08:59 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>, Mel Gorman <mgorman@...e.de>
Subject: [PATCH 12/15] sched: Remove check that skips small VMAs

task_numa_work skips small VMAs. At the time the logic was to reduce the
scanning overhead which was considerable. It is a dubious hack at best.
It would make much more sense to cache where faults have been observed
and only rescan those regions during subsequent PTE scans. Remove this
hack as motivation to do it properly in the future.

Signed-off-by: Mel Gorman <mgorman@...e.de>
---
 kernel/sched/fair.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 66306c7..47276a3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1089,10 +1089,6 @@ void task_numa_work(struct callback_head *work)
 		if (!vma_migratable(vma))
 			continue;
 
-		/* Skip small VMAs. They are not likely to be of relevance */
-		if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
-			continue;
-
 		do {
 			start = max(start, vma->vm_start);
 			end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
-- 
1.8.1.4

--
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/