linux-kernel - [PATCH] ksm: make rmap walks more scalable

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: <alpine.LNX.2.00.1212191742440.25409@eggly.anvils>
Date:	Wed, 19 Dec 2012 17:44:29 -0800 (PST)
From:	Hugh Dickins <hughd@...gle.com>
To:	Mel Gorman <mgorman@...e.de>
cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>,
	Sasha Levin <sasha.levin@...cle.com>,
	Petr Holasek <pholasek@...hat.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH] ksm: make rmap walks more scalable

The rmap walks in ksm.c are like those in rmap.c:
they can safely be done with anon_vma_lock_read().

Signed-off-by: Hugh Dickins <hughd@...gle.com>
---

 mm/ksm.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- 3.7+git/mm/ksm.c	2012-12-16 16:35:08.752441527 -0800
+++ linux/mm/ksm.c	2012-12-19 16:58:05.292145790 -0800
@@ -1624,7 +1624,7 @@ again:
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
 
-		anon_vma_lock_write(anon_vma);
+		anon_vma_lock_read(anon_vma);
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
 			vma = vmac->vma;
@@ -1648,7 +1648,7 @@ again:
 			if (!search_new_forks || !mapcount)
 				break;
 		}
-		anon_vma_unlock(anon_vma);
+		anon_vma_unlock_read(anon_vma);
 		if (!mapcount)
 			goto out;
 	}
@@ -1678,7 +1678,7 @@ again:
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
 
-		anon_vma_lock_write(anon_vma);
+		anon_vma_lock_read(anon_vma);
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
 			vma = vmac->vma;
@@ -1697,11 +1697,11 @@ again:
 			ret = try_to_unmap_one(page, vma,
 					rmap_item->address, flags);
 			if (ret != SWAP_AGAIN || !page_mapped(page)) {
-				anon_vma_unlock(anon_vma);
+				anon_vma_unlock_read(anon_vma);
 				goto out;
 			}
 		}
-		anon_vma_unlock(anon_vma);
+		anon_vma_unlock_read(anon_vma);
 	}
 	if (!search_new_forks++)
 		goto again;
@@ -1731,7 +1731,7 @@ again:
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
 
-		anon_vma_lock_write(anon_vma);
+		anon_vma_lock_read(anon_vma);
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
 			vma = vmac->vma;
@@ -1749,11 +1749,11 @@ again:
 
 			ret = rmap_one(page, vma, rmap_item->address, arg);
 			if (ret != SWAP_AGAIN) {
-				anon_vma_unlock(anon_vma);
+				anon_vma_unlock_read(anon_vma);
 				goto out;
 			}
 		}
-		anon_vma_unlock(anon_vma);
+		anon_vma_unlock_read(anon_vma);
 	}
 	if (!search_new_forks++)
 		goto again;
--
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/