From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id 2761F6B00E9 for ; Wed, 12 Nov 2014 04:51:49 -0500 (EST) Received: by mail-pa0-f53.google.com with SMTP id kx10so12604070pab.40 for ; Wed, 12 Nov 2014 01:51:48 -0800 (PST) Received: from mailout3.samsung.com (mailout3.samsung.com. [203.254.224.33]) by mx.google.com with ESMTPS id gj10si22213986pbc.248.2014.11.12.01.51.47 for (version=TLSv1 cipher=RC4-MD5 bits=128/128); Wed, 12 Nov 2014 01:51:47 -0800 (PST) Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NEX004WG7E8NED0@mailout3.samsung.com> for linux-mm@kvack.org; Wed, 12 Nov 2014 18:51:45 +0900 (KST) From: Weijie Yang Subject: [RFC PATCH] mm: mincore: use PAGE_SIZE instead of PAGE_CACHE_SIZE Date: Wed, 12 Nov 2014 17:50:37 +0800 Message-id: <000001cffe5e$44893f60$cd9bbe20$%yang@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 7bit Content-language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Johannes Weiner' Cc: 'Andrew Morton' , mgorman@suse.de, 'Rik van Riel' , 'Weijie Yang' , 'Linux-MM' , 'linux-kernel' This is a RFC patch, because current PAGE_SIZE is equal to PAGE_CACHE_SIZE, there isn't any difference and issue when running. However, the current code mixes these two aligned_size inconsistently, and if they are not equal in future mincore_unmapped_range() would check more file pages than wanted. According to man-page, mincore uses PAGE_SIZE as its size unit, so this patch uses PAGE_SIZE instead of PAGE_CACHE_SIZE. Signed-off-by: Weijie Yang --- mm/mincore.c | 19 +++++++++++++------ 1 files changed, 13 insertions(+), 6 deletions(-) diff --git a/mm/mincore.c b/mm/mincore.c index 725c809..8c19bce 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -102,11 +102,18 @@ static void mincore_unmapped_range(struct vm_area_struct *vma, int i; if (vma->vm_file) { - pgoff_t pgoff; + pgoff_t pgoff, pgoff_end; + int j, count; + unsigned char res; + count = 1 << (PAGE_CACHE_SHIFT - PAGE_SHIFT); pgoff = linear_page_index(vma, addr); - for (i = 0; i < nr; i++, pgoff++) - vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff); + pgoff_end = linear_page_index(vma, end); + for (i = 0; pgoff < pgoff_end; pgoff++) { + res = mincore_page(vma->vm_file->f_mapping, pgoff); + for (j = 0; j < count; j++) + vec[i++] = res; + } } else { for (i = 0; i < nr; i++) vec[i] = 0; @@ -258,7 +265,7 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v * return values: * zero - success * -EFAULT - vec points to an illegal address - * -EINVAL - addr is not a multiple of PAGE_CACHE_SIZE + * -EINVAL - addr is not a multiple of PAGE_SIZE * -ENOMEM - Addresses in the range [addr, addr + len] are * invalid for the address space of this process, or * specify one or more pages which are not currently @@ -273,14 +280,14 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len, unsigned char *tmp; /* Check the start address: needs to be page-aligned.. */ - if (start & ~PAGE_CACHE_MASK) + if (start & ~PAGE_MASK) return -EINVAL; /* ..and we need to be passed a valid user-space range */ if (!access_ok(VERIFY_READ, (void __user *) start, len)) return -ENOMEM; - /* This also avoids any overflows on PAGE_CACHE_ALIGN */ + /* This also avoids any overflows on PAGE_ALIGN */ pages = len >> PAGE_SHIFT; pages += (len & ~PAGE_MASK) != 0; -- 1.7.0.4 -- 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