From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f172.google.com (mail-ig0-f172.google.com [209.85.213.172]) by kanga.kvack.org (Postfix) with ESMTP id 6E7916B0032 for ; Wed, 10 Dec 2014 10:02:48 -0500 (EST) Received: by mail-ig0-f172.google.com with SMTP id hl2so6561038igb.5 for ; Wed, 10 Dec 2014 07:02:48 -0800 (PST) Received: from mail-ie0-x22e.google.com (mail-ie0-x22e.google.com. [2607:f8b0:4001:c03::22e]) by mx.google.com with ESMTPS id qg1si3376788igb.22.2014.12.10.07.02.46 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 10 Dec 2014 07:02:47 -0800 (PST) Received: by mail-ie0-f174.google.com with SMTP id rl12so2810308iec.19 for ; Wed, 10 Dec 2014 07:02:46 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <000001cffe5e$44893f60$cd9bbe20$%yang@samsung.com> References: <000001cffe5e$44893f60$cd9bbe20$%yang@samsung.com> Date: Wed, 10 Dec 2014 23:02:46 +0800 Message-ID: Subject: Re: [RFC PATCH] mm: mincore: use PAGE_SIZE instead of PAGE_CACHE_SIZE From: Weijie Yang Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Weijie Yang Cc: Johannes Weiner , Andrew Morton , Mel Gorman , Rik van Riel , Linux-MM , linux-kernel ping. Any comments? On Wed, Nov 12, 2014 at 5:50 PM, Weijie Yang wrote: > 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