From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754837AbbCSLj0 (ORCPT ); Thu, 19 Mar 2015 07:39:26 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:38340 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754618AbbCSLjY (ORCPT ); Thu, 19 Mar 2015 07:39:24 -0400 X-AuditID: cbfee6a4-f79bd6d000003ec3-e2-550ab56a2e7c Date: Thu, 19 Mar 2015 11:39:22 +0000 (GMT) From: Yinghao Xie Subject: mm/zsmalloc.c: count in handle's size when calculating pages_per_zspage To: Andrew Morton Cc: Minchan Kim , Nitin Gupta , mm , lkml Reply-to: yinghao.xie@samsung.com MIME-version: 1.0 X-MTR: 20150319094238974@yinghao.xie Msgkey: 20150319094238974@yinghao.xie X-EPLocale: zh_CN.utf-8 X-Priority: 3 X-EPWebmail-Msg-Type: personal X-EPWebmail-Reply-Demand: 0 X-EPApproval-Locale: X-EPHeader: ML X-MLAttribute: X-RootMTR: 20150319094238974@yinghao.xie X-ParentMTR: X-ArchiveUser: X-CPGSPASS: N X-ConfirmMail: N,general Content-type: text/plain; charset=utf-8 MIME-version: 1.0 Message-id: <430707086.362221426765159948.JavaMail.weblogic@epmlwas05d> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrPIsWRmVeSWpSXmKPExsVy+t/tft2srVyhBqsP8lhc3jWHzYHR4/Mm uQDGKC6blNSczLLUIn27BK6MySs/sxbcka/YNGMZewPjB7kuRk4OIQE1iY4Vr5lAbAkBE4k9 SxZA2WISF+6tZ+ti5AKqmcMocf/Cb7AEi4CqxIq9/4FsDg42AR2Jbcd0QMLCAoESfbtbWUFs EQF9iXlLJjOB9DILTGSUONYxiQlimaJEw+vVLCA2r4CgxMmZT1gglqlIzPx/FyquKvF37TJW iLi4xKeJV9kgbF6JGe1PoerlJKZ9XcMMYUtLnJ+1gRHm6MXfH0PF+SWO3d4B9YyAxNQzB6Fq NCXOn/sKVcMnsWbhWxaY+l2nljPD7Lq/ZS5Ur4TE1pYnYPcwA90/pfshO8jvzEBz1u/SR/cK r4C7RN/5v6wTGGVnIUnNQtI9C6EbWckCRpZVjKKpBckFxUnpFSZ6xYm5xaV56XrJ+bmbGMHR /GzJDsaGC9aHGAU4GJV4eDPcuUKFWBPLiitzDzFKcDArifCeLgMK8aYkVlalFuXHF5XmpBYf YpTmYFES5/1/LjdESCA9sSQ1OzW1ILUIJsvEwSnVwNj6QXLiRFM7tf0i9wT3JNoVHve7vOHh 18W6e71KPyYsfrtkX2zvksPlm6erZpbcC+j/oWfBeEotZIPijklv1/3kald+01EmvsehlXV/ wGW7/GrWI3dmlL8OSJnWtvj7AWX1lNbXmrsSHvdnJvnc5/1w72nxWnP1R/vv9vKciNWenhAi IPySM12JpTgj0VCLuag4EQBx+cbO4gIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id t2JBdVlU016383 >>From 159d74b5a8f3d0f07e18ddad74b7025cf17dcc69 Mon Sep 17 00:00:00 2001 From: Yinghao Xie Date: Thu, 19 Mar 2015 19:32:25 +0800 Subject: [PATCH] mm/zsmalloc.c: count in handle's size when calculating size_class's pages_per_zspage 1. Fix wastage calculation; 2. Indirect handle introduced extra ZS_HANDLE_SIZE size for each object,it's transparent for upper function, but a size_class's total objects will changed: take the 43rd class which class_size = 32 + 43 * 16 = 720 as example: 4096 * 1 % 720 = 496 4096 * 2 % 720 = 272 4096 * 3 % 720 = 48 4096 * 4 %720 = 544 after handle introduced,class_size + ZS_HANDLE_SIZE (4 on 32bit) = 724 4096 * 1 % 724 = 476 4096 * 2 % 724 = 228 4096 * 3 % 724 = 704 4096 * 4 % 724 = 456 Clearly, ZS_HANDLE_SIZE should be considered when calculating pages_per_zspage; 3. in get_size_class_index(), min(zs_size_classes - 1, idx) insures a huge class's index <= zs_size_classes - 1, so it's no need to check again; Signed-off-by: Yinghao Xie --- mm/zsmalloc.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 461243e..64c379b 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -760,7 +760,8 @@ out: * to form a zspage for each size class. This is important * to reduce wastage due to unusable space left at end of * each zspage which is given as: - * wastage = Zp - Zp % size_class + * wastage = Zp % (class_size + ZS_HANDLE_SIZE) + * usage = Zp - wastage * where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ... * * For example, for size class of 3/8 * PAGE_SIZE, we should @@ -773,6 +774,9 @@ static int get_pages_per_zspage(int class_size) /* zspage order which gives maximum used size per KB */ int max_usedpc_order = 1; + if (class_size > ZS_MAX_ALLOC_SIZE) + class_size = ZS_MAX_ALLOC_SIZE; + for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { int zspage_size; int waste, usedpc; @@ -1426,11 +1430,6 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size) /* extra space in chunk to keep the handle */ size += ZS_HANDLE_SIZE; class = pool->size_class[get_size_class_index(size)]; - /* In huge class size, we store the handle into first_page->private */ - if (class->huge) { - size -= ZS_HANDLE_SIZE; - class = pool->size_class[get_size_class_index(size)]; - } spin_lock(&class->lock); first_page = find_get_zspage(class); @@ -1856,9 +1855,7 @@ struct zs_pool *zs_create_pool(char *name, gfp_t flags) struct size_class *class; size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA; - if (size > ZS_MAX_ALLOC_SIZE) - size = ZS_MAX_ALLOC_SIZE; - pages_per_zspage = get_pages_per_zspage(size); + pages_per_zspage = get_pages_per_zspage(size + ZS_HANDLE_SIZE); /* * size_class is used for normal zsmalloc operation such -- 1.7.9.5 {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I