From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>,
Christoph Lameter <cl@linux.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@lge.com,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address")
Date: Tue, 18 Apr 2017 19:56:41 +0900 [thread overview]
Message-ID: <20170418105641.GC558@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20170418073307.GF22360@dhcp22.suse.cz>
On (04/18/17 09:33), Michal Hocko wrote:
[..]
> > Another approach is the API does normal thing for non-aligned prefix and
> > tail space and fast thing for aligned space.
> > Otherwise, it would be happy if the API has WARN_ON non-page SIZE aligned
> > address.
>
> copy_page is a performance sensitive function and I believe that we do
> those tricks exactly for this purpose.
a wild thought,
use
#define copy_page(to,from) memcpy((to), (from), PAGE_SIZE)
when DEBUG_SLAB is set? so arch copy_page() (if provided by arch)
won't be affected otherwise.
-ss
next prev parent reply other threads:[~2017-04-18 10:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-17 1:48 copy_page() on a kmalloc-ed page with DEBUG_SLAB enabled (was "zram: do not use copy_page with non-page alinged address") Sergey Senozhatsky
2017-04-17 15:20 ` Christoph Lameter
2017-04-18 0:03 ` Minchan Kim
2017-04-18 7:33 ` Michal Hocko
2017-04-18 10:56 ` Sergey Senozhatsky [this message]
2017-04-18 11:06 ` Michal Hocko
2017-04-19 6:11 ` Sergey Senozhatsky
2017-04-19 6:02 ` Minchan Kim
2017-04-19 11:51 ` Matthew Wilcox
2017-04-20 1:45 ` Sergey Senozhatsky
2017-04-20 6:50 ` Minchan Kim
2017-04-18 10:42 ` Sergey Senozhatsky
2017-04-18 13:28 ` Christoph Lameter
2017-04-18 13:13 ` Matthew Wilcox
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=20170418105641.GC558@jagdpanzerIV.localdomain \
--to=sergey.senozhatsky.work@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=kernel-team@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=minchan@kernel.org \
--cc=sergey.senozhatsky@gmail.com \
--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).