linux-kernel - [RFC PATCH v3 10/35] mm: Use the correct migratetype during buddy merging

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: <20130830131654.4947.85409.stgit@srivatsabhat.in.ibm.com>
Date:	Fri, 30 Aug 2013 18:46:56 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	akpm@...ux-foundation.org, mgorman@...e.de, hannes@...xchg.org,
	tony.luck@...el.com, matthew.garrett@...ula.com, dave@...1.net,
	riel@...hat.com, arjan@...ux.intel.com,
	srinivas.pandruvada@...ux.intel.com, willy@...ux.intel.com,
	kamezawa.hiroyu@...fujitsu.com, lenb@...nel.org, rjw@...k.pl
Cc:	gargankita@...il.com, paulmck@...ux.vnet.ibm.com,
	svaidy@...ux.vnet.ibm.com, andi@...stfloor.org,
	isimatu.yasuaki@...fujitsu.com, santosh.shilimkar@...com,
	kosaki.motohiro@...il.com, srivatsa.bhat@...ux.vnet.ibm.com,
	linux-pm@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH v3 10/35] mm: Use the correct migratetype during buddy
 merging

While merging buddy free pages of a given order to make a higher order page,
the buddy allocator might coalesce pages belonging to *two* *different*
migratetypes of that order!

So, don't assume that both the buddies come from the same freelist;
instead, explicitly find out the migratetype info of the buddy page and use
it while merging the buddies.

Also, set the freepage migratetype of the buddy to the new one.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 mm/page_alloc.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b4b1275..07ac019 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -681,10 +681,14 @@ static inline void __free_one_page(struct page *page,
 			__mod_zone_freepage_state(zone, 1 << order,
 						  migratetype);
 		} else {
+			int mt;
+
 			area = &zone->free_area[order];
-			del_from_freelist(buddy, &area->free_list[migratetype]);
+			mt = get_freepage_migratetype(buddy);
+			del_from_freelist(buddy, &area->free_list[mt]);
 			area->nr_free--;
 			rmv_page_order(buddy);
+			set_freepage_migratetype(buddy, migratetype);
 		}
 		combined_idx = buddy_idx & page_idx;
 		page = page + (combined_idx - page_idx);

--
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/