linux-kernel - [patch] memory reclaim more efficiently

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-next>] [day] [month] [year] [list]

Message-ID: <485EF481.30409@ah.jp.nec.com>
Date:	Mon, 23 Jun 2008 09:55:29 +0900
From:	Takenori Nagano <t-nagano@...jp.nec.com>
To:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
CC:	Keiichi KII <kii@...ux.bs1.fc.nec.co.jp>
Subject: [patch] memory reclaim more  efficiently

Hi,

Efficiency of memory reclaim is recently one of the hot topics. (LRU splitting,
pageout throttling, etc...) I would like to contribute it and I made this patch.

In shrink_zone(), system can not return to user mode before it finishes to
search LRU list. IMHO, it is very wasteful, since the user processes stay
unnecessarily long time in shrink_zone() loop and application response time
becomes relatively bad. This patch changes shrink_zone() that it finishes memory
reclaim when it reclaims enough memory.

the conditions to end searching:

1. order of request page is 0
2. process is not kswapd.
3. satisfy the condition to return try_to_free_pages()
   # nr_reclaim > SWAP_CLUSTER_MAX

Signed-off-by: Takenori Nagano <t-nagano@...jp.nec.com>
Signed-off-by: Keiichi Kii <k-keiichi@...jp.nec.com>

---
diff -uprN linux-2.6.26-rc6.orig/mm/vmscan.c linux-2.6.26-rc6/mm/vmscan.c
--- linux-2.6.26-rc6.orig/mm/vmscan.c	2008-06-13 06:22:24.000000000 +0900
+++ linux-2.6.26-rc6/mm/vmscan.c	2008-06-20 15:05:03.492700863 +0900
@@ -1224,6 +1224,9 @@ static unsigned long shrink_zone(int pri
 			nr_reclaimed += shrink_inactive_list(nr_to_scan, zone,
 								sc);
 		}
+		if (nr_reclaimed > sc->swap_cluster_max && !sc->order
+						&& !current_is_kswapd())
+			break;
 	}

 	throttle_vm_writeout(sc->gfp_mask);

--
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/