From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id A5A0C6B0033 for ; Fri, 9 Aug 2013 06:22:34 -0400 (EDT) Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MR900DB4E4XUP80@mailout1.w1.samsung.com> for linux-mm@kvack.org; Fri, 09 Aug 2013 11:22:32 +0100 (BST) From: Krzysztof Kozlowski Subject: [RFC PATCH v2 0/4] mm: reclaim zbud pages on migration and compaction Date: Fri, 09 Aug 2013 12:22:16 +0200 Message-id: <1376043740-10576-1-git-send-email-k.kozlowski@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: Seth Jennings , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Cc: Mel Gorman , Bartlomiej Zolnierkiewicz , Marek Szyprowski , Kyungmin Park , Dave Hansen , Krzysztof Kozlowski Hi, Currently zbud pages are not movable and they cannot be allocated from CMA region. These patches try to address the problem by: 1. Adding a new form of reclaim of zbud pages. 2. Reclaiming zbud pages during migration and compaction. 3. Allocating zbud pages with __GFP_RECLAIMABLE flag. This reclaim process is different than zbud_reclaim_page(). It acts more like swapoff() by trying to unuse pages stored in zbud page and bring them back to memory. The standard zbud_reclaim_page() on the other hand tries to write them back. One of patches introduces PageZbud() function which identifies zbud pages my page->_mapcount. Dave Hansen proposed aliasing PG_zbud=PG_slab but in such case patch would be more intrusive. Any ideas for a better solution are welcome. TODO-s: 1. Migrate zbud pages directly instead of reclaiming. Changes since v1: 1. Rebased against v3.11-rc4-103-g6c2580c. 2. Remove rebalance_lists() to fix reinserting zbud page after zbud_free. This function was added because similar code was present in zbud_free/zbud_alloc/zbud_reclaim_page but it turns out that there is no benefit in generalizing this code. (suggested by Seth Jennings) 3. Remove BUG_ON checks for first/last chunks during free and reclaim. (suggested by Seth Jennings) 4. Use page->_mapcount==-127 instead of new PG_zbud flag. (suggested by Dave Hansen) 5. Fix invalid dereference of pointer to compact_control in page_alloc.c. 6. Fix lost return value in try_to_unuse() in swapfile.c (this fixes hang when swapoff was interrupted e.g. by CTRL+C). Best regards, Krzysztof Kozlowski Krzysztof Kozlowski (4): zbud: use page ref counter for zbud pages mm: split code for unusing swap entries from try_to_unuse mm: use mapcount for identifying zbud pages mm: reclaim zbud pages on migration and compaction include/linux/mm.h | 23 +++ include/linux/swapfile.h | 2 + include/linux/zbud.h | 11 +- mm/compaction.c | 20 ++- mm/internal.h | 1 + mm/page_alloc.c | 6 + mm/swapfile.c | 356 ++++++++++++++++++++++++---------------------- mm/zbud.c | 247 +++++++++++++++++++++++--------- mm/zswap.c | 57 +++++++- 9 files changed, 476 insertions(+), 247 deletions(-) -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org