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From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	mgorman@suse.de
Subject: Re: [PATCH] mm: cma: fix accounting of CMA pages placed in high memory
Date: Tue, 05 Feb 2013 09:38:30 +0100	[thread overview]
Message-ID: <5110C506.2060209@samsung.com> (raw)
In-Reply-To: <20130205004032.GD2610@blaptop>

Hello,

On 2/5/2013 1:40 AM, Minchan Kim wrote:

...

> > Previous time, it's not fully tested and now we checked it with
> > highmem support patches.
>
> I get it. Sigh. then [1] inline attached below wan't good.
> We have to code like this?
>
> [1] 6a6dccba, mm: cma: don't replace lowmem pages with highmem
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b97cf12..0707e0a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5671,11 +5671,10 @@ static struct page *
>   __alloc_contig_migrate_alloc(struct page *page, unsigned long private,
>                               int **resultp)
>   {
> -       gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
> -
> -       if (PageHighMem(page))
> -               gfp_mask |= __GFP_HIGHMEM;
> -
> +       gfp_t gfp_mask = GFP_HIGHUSER_MOVABLE;
> +       struct address_space *mapping = page_mapping(page);
> +       if (mapping)
> +               gfp_mask = mapping_gfp_mask(mapping);
>          return alloc_page(gfp_mask);
>   }

Am I right that this code will allocate more pages from himem? Old approach
never migrate lowmem page to himem, what is now possible as gfp mask is 
always
taken from mapping_gfp flags. I only wonder if forcing GFP_HIGHUSER_MOVABLE
for pages without the mapping is a correct. Shouldn't we use avoid himem in
such case?

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center


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WARNING: multiple messages have this Message-ID (diff)
From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	mgorman@suse.de
Subject: Re: [PATCH] mm: cma: fix accounting of CMA pages placed in high memory
Date: Tue, 05 Feb 2013 09:38:30 +0100	[thread overview]
Message-ID: <5110C506.2060209@samsung.com> (raw)
In-Reply-To: <20130205004032.GD2610@blaptop>

Hello,

On 2/5/2013 1:40 AM, Minchan Kim wrote:

...

> > Previous time, it's not fully tested and now we checked it with
> > highmem support patches.
>
> I get it. Sigh. then [1] inline attached below wan't good.
> We have to code like this?
>
> [1] 6a6dccba, mm: cma: don't replace lowmem pages with highmem
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b97cf12..0707e0a 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5671,11 +5671,10 @@ static struct page *
>   __alloc_contig_migrate_alloc(struct page *page, unsigned long private,
>                               int **resultp)
>   {
> -       gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
> -
> -       if (PageHighMem(page))
> -               gfp_mask |= __GFP_HIGHMEM;
> -
> +       gfp_t gfp_mask = GFP_HIGHUSER_MOVABLE;
> +       struct address_space *mapping = page_mapping(page);
> +       if (mapping)
> +               gfp_mask = mapping_gfp_mask(mapping);
>          return alloc_page(gfp_mask);
>   }

Am I right that this code will allocate more pages from himem? Old approach
never migrate lowmem page to himem, what is now possible as gfp mask is 
always
taken from mapping_gfp flags. I only wonder if forcing GFP_HIGHUSER_MOVABLE
for pages without the mapping is a correct. Shouldn't we use avoid himem in
such case?

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center



  reply	other threads:[~2013-02-05  8:38 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-04 10:27 [PATCH] mm: cma: fix accounting of CMA pages placed in high memory Marek Szyprowski
2013-02-04 10:27 ` Marek Szyprowski
2013-02-04 12:55 ` Kyungmin Park
2013-02-04 23:06 ` Andrew Morton
2013-02-04 23:06   ` Andrew Morton
2013-02-04 23:29   ` Kyungmin Park
2013-02-04 23:29     ` Kyungmin Park
2013-02-04 23:43     ` Minchan Kim
2013-02-04 23:43       ` Minchan Kim
2013-02-04 23:52       ` Kyungmin Park
2013-02-04 23:52         ` Kyungmin Park
2013-02-05  0:40         ` Minchan Kim
2013-02-05  0:40           ` Minchan Kim
2013-02-05  8:38           ` Marek Szyprowski [this message]
2013-02-05  8:38             ` Marek Szyprowski
2013-02-05  8:47             ` Minchan Kim
2013-02-05  8:47               ` Minchan Kim
2013-02-05  8:28     ` Mel Gorman
2013-02-05  8:28       ` Mel Gorman
2013-02-05  8:56       ` Marek Szyprowski
2013-02-05  8:56         ` Marek Szyprowski
2013-02-04 23:34 ` Minchan Kim
2013-02-04 23:34   ` Minchan Kim
2013-02-05  7:10   ` Marek Szyprowski
2013-02-05  7:10     ` Marek Szyprowski
2013-02-05  7:34     ` Minchan Kim
2013-02-05  7:34       ` Minchan Kim
2013-02-19 13:27     ` Simon Jeons
2013-02-19 13:27       ` Simon Jeons
2013-02-20  2:57       ` Kyungmin Park
2013-02-20  2:57         ` Kyungmin Park
2013-02-20  5:31         ` Simon Jeons
2013-02-20  5:31           ` Simon Jeons

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