From: Christoph Hellwig <hch@infradead.org>
To: js1304@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Vlastimil Babka <vbabka@suse.cz>,
Laura Abbott <labbott@redhat.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <guro@fb.com>, Minchan Kim <minchan@kernel.org>,
Rik van Riel <riel@surriel.com>,
Christian Koenig <christian.koenig@amd.com>,
Huang Rui <ray.huang@amd.com>,
Eric Biederman <ebiederm@xmission.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Pavel Machek <pavel@ucw.cz>, Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 03/10] mm/migrate: separate PageHighMem() and PageHighMemZone() use case
Date: Wed, 22 Apr 2020 00:44:23 -0700 [thread overview]
Message-ID: <20200422074423.GA12288@infradead.org> (raw)
In-Reply-To: <1587369582-3882-4-git-send-email-iamjoonsoo.kim@lge.com>
On Mon, Apr 20, 2020 at 04:59:35PM +0900, js1304@gmail.com wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> Until now, PageHighMem() is used for two different cases. One is to check
> if there is a direct mapping for this page or not. The other is to check
> the zone of this page, that is, weather it is the highmem type zone or not.
>
> Now, we have separate functions, PageHighMem() and PageHighMemZone() for
> each cases. Use appropriate one.
>
> Note that there are some rules to determine the proper macro.
>
> 1. If PageHighMem() is called for checking if the direct mapping exists
> or not, use PageHighMem().
> 2. If PageHighMem() is used to predict the previous gfp_flags for
> this page, use PageHighMemZone(). The zone of the page is related to
> the gfp_flags.
> 3. If purpose of calling PageHighMem() is to count highmem page and
> to interact with the system by using this count, use PageHighMemZone().
> This counter is usually used to calculate the available memory for an
> kernel allocation and pages on the highmem zone cannot be available
> for an kernel allocation.
> 4. Otherwise, use PageHighMemZone(). It's safe since it's implementation
> is just copy of the previous PageHighMem() implementation and won't
> be changed.
>
> I apply the rule #2 for this patch.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> ---
> include/linux/migrate.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index 3e546cb..9a57766 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -47,7 +47,7 @@ static inline struct page *new_page_nodemask(struct page *page,
> order = HPAGE_PMD_ORDER;
> }
>
> - if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
> + if (PageHighMemZone(page) || zone_idx(page_zone(page)) == ZONE_MOVABLE)
> gfp_mask |= __GFP_HIGHMEM;
I think this would be much cleaner if you open coded PageHighMemZone
here.
E.g.
int zone = page_zone(page);
if (is_highmem_idx(zone) || zone_idx(zone) == ZONE_MOVABLE)
next prev parent reply other threads:[~2020-04-22 7:44 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 7:59 [PATCH 00/10] change the implemenation of the PageHighMem() js1304
2020-04-20 7:59 ` [PATCH 01/10] mm/page-flags: introduce PageHighMemZone() js1304
2020-04-20 11:20 ` Matthew Wilcox
2020-04-20 11:37 ` Vlastimil Babka
2020-04-21 6:43 ` Joonsoo Kim
2021-02-10 12:56 ` Prakash Gupta
2020-04-21 9:00 ` Christoph Hellwig
2020-04-22 1:02 ` Roman Gushchin
2020-04-22 7:42 ` Joonsoo Kim
2020-04-22 7:40 ` Joonsoo Kim
2020-04-20 7:59 ` [PATCH 02/10] drm/ttm: separate PageHighMem() and PageHighMemZone() use case js1304
2020-04-20 8:42 ` Christian König
2020-04-21 6:49 ` Joonsoo Kim
2020-04-20 7:59 ` [PATCH 03/10] mm/migrate: " js1304
2020-04-22 7:44 ` Christoph Hellwig [this message]
2020-04-22 7:55 ` Joonsoo Kim
2020-04-20 7:59 ` [PATCH 04/10] kexec: " js1304
2020-04-20 7:59 ` [PATCH 05/10] power: " js1304
2020-04-20 7:59 ` [PATCH 06/10] mm/gup: " js1304
2020-04-20 7:59 ` [PATCH 07/10] mm/hugetlb: " js1304
2020-04-20 7:59 ` [PATCH 08/10] mm: " js1304
2020-04-20 7:59 ` [PATCH 09/10] mm/page_alloc: correct the use of is_highmem_idx() js1304
2020-04-20 7:59 ` [PATCH 10/10] mm/page-flags: change the implementation of the PageHighMem() js1304
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200422074423.GA12288@infradead.org \
--to=hch@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.ibm.com \
--cc=christian.koenig@amd.com \
--cc=ebiederm@xmission.com \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=iamjoonsoo.kim@lge.com \
--cc=js1304@gmail.com \
--cc=labbott@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=pavel@ucw.cz \
--cc=ray.huang@amd.com \
--cc=riel@surriel.com \
--cc=rjw@rjwysocki.net \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).