From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Steve Capper <steve.capper@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
shijie.huang@arm.com, will.deacon@arm.com,
catalin.marinas@arm.com
Subject: Re: [PATCH] rmap: Fix compound check logic in page_remove_file_rmap
Date: Tue, 9 Aug 2016 19:29:15 +0300 [thread overview]
Message-ID: <20160809162915.GA10293@node.shutemov.name> (raw)
In-Reply-To: <1470746075-20856-1-git-send-email-steve.capper@arm.com>
On Tue, Aug 09, 2016 at 01:34:35PM +0100, Steve Capper wrote:
> In page_remove_file_rmap(.) we have the following check:
> VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
>
> This is meant to check for either HugeTLB pages or THP when a compound
> page is passed in.
>
> Unfortunately, if one disables CONFIG_TRANSPARENT_HUGEPAGE, then
> PageTransHuge(.) will always return false provoking BUGs when one runs
> the libhugetlbfs test suite.
>
> Changing the definition of PageTransHuge to be defined for
> !CONFIG_TRANSPARENT_HUGEPAGE turned out to provoke build bugs; so this
> patch instead replaces the errant check with:
> PageTransHuge(page) || PageHuge(page)
I think PageHead() check should be enough to cover this.
>
> Fixes: dd78fedde4b9 ("rmap: support file thp")
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Steve Capper <steve.capper@arm.com>
> ---
> mm/rmap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 709bc83..ad8fc51 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1303,7 +1303,7 @@ static void page_remove_file_rmap(struct page *page, bool compound)
> {
> int i, nr = 1;
>
> - VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
> + VM_BUG_ON_PAGE(compound && !(PageTransHuge(page) || PageHuge(page)), page);
> lock_page_memcg(page);
>
> /* Hugepages are not counted in NR_FILE_MAPPED for now. */
> --
> 1.8.3.1
>
> --
> 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Kirill A. Shutemov
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Steve Capper <steve.capper@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
shijie.huang@arm.com, will.deacon@arm.com,
catalin.marinas@arm.com
Subject: Re: [PATCH] rmap: Fix compound check logic in page_remove_file_rmap
Date: Tue, 9 Aug 2016 19:29:15 +0300 [thread overview]
Message-ID: <20160809162915.GA10293@node.shutemov.name> (raw)
In-Reply-To: <1470746075-20856-1-git-send-email-steve.capper@arm.com>
On Tue, Aug 09, 2016 at 01:34:35PM +0100, Steve Capper wrote:
> In page_remove_file_rmap(.) we have the following check:
> VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
>
> This is meant to check for either HugeTLB pages or THP when a compound
> page is passed in.
>
> Unfortunately, if one disables CONFIG_TRANSPARENT_HUGEPAGE, then
> PageTransHuge(.) will always return false provoking BUGs when one runs
> the libhugetlbfs test suite.
>
> Changing the definition of PageTransHuge to be defined for
> !CONFIG_TRANSPARENT_HUGEPAGE turned out to provoke build bugs; so this
> patch instead replaces the errant check with:
> PageTransHuge(page) || PageHuge(page)
I think PageHead() check should be enough to cover this.
>
> Fixes: dd78fedde4b9 ("rmap: support file thp")
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Steve Capper <steve.capper@arm.com>
> ---
> mm/rmap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 709bc83..ad8fc51 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1303,7 +1303,7 @@ static void page_remove_file_rmap(struct page *page, bool compound)
> {
> int i, nr = 1;
>
> - VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
> + VM_BUG_ON_PAGE(compound && !(PageTransHuge(page) || PageHuge(page)), page);
> lock_page_memcg(page);
>
> /* Hugepages are not counted in NR_FILE_MAPPED for now. */
> --
> 1.8.3.1
>
> --
> 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2016-08-09 16:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-09 12:34 [PATCH] rmap: Fix compound check logic in page_remove_file_rmap Steve Capper
2016-08-09 12:34 ` Steve Capper
2016-08-09 16:29 ` Kirill A. Shutemov [this message]
2016-08-09 16:29 ` Kirill A. Shutemov
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