From: Richard Weinberger <richard@nod.at>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-mtd@lists.infradead.org, hannes@cmpxchg.org,
mgorman@techsingularity.net, n-horiguchi@ah.jp.nec.com,
kirill.shutemov@linux.intel.com, hughd@google.com,
vbabka@suse.cz, adrian.hunter@intel.com, dedekind1@gmail.com,
hch@infradead.org, linux-fsdevel@vger.kernel.org,
boris.brezillon@free-electrons.com,
maxime.ripard@free-electrons.com, david@sigma-star.at,
david@fromorbit.com, alex@nextthing.co, sasha.levin@oracle.com,
iamjoonsoo.kim@lge.com, rvaswani@codeaurora.org,
tony.luck@intel.com, shailendra.capricorn@gmail.com
Subject: Re: [PATCH 1/3] mm: Don't blindly assign fallback_migrate_page()
Date: Fri, 17 Jun 2016 18:55:45 +0200 [thread overview]
Message-ID: <57642B91.4020206@nod.at> (raw)
In-Reply-To: <20160617162803.GK21670@dhcp22.suse.cz>
Am 17.06.2016 um 18:28 schrieb Michal Hocko:
> But doesn't this disable the page migration and so potentially reduce
> the compaction success rate for the large pile of filesystems? Without
> any hint about that?
The WARN_ON_ONCE() is the hint. ;)
But I can understand your point we'd have to communicate that change better.
> $ git grep "\.migratepage[[:space:]]*=" -- fs | wc -l
> 16
> out of
> $ git grep "struct address_space_operations[[:space:]]*[a-zA-Z0-9_]*[[:space:]]*=" -- fs | wc -l
> 87
>
> That just seems to be too conservative for something that even not might
> be a problem, especially when considering the fallback migration code is
> there for many years with only UBIFS seeing a problem.
UBIFS is also there for many years.
It just shows that the issue is hard to hit but at least for UBIFS it is real.
> Wouldn't it be safer to contact FS developers who might have have
> similar issue and work with them to use a proper migration code?
That was the goal of this patch. Forcing the filesystem developers
to look as the WARN_ON_ONCE() triggered.
I fear just sending a mail to linux-fsdevel@vger is not enough.
Thanks,
//richard
next prev parent reply other threads:[~2016-06-17 16:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 21:26 Remove page migration fallback (was: UBIFS and page migration) Richard Weinberger
2016-06-16 21:26 ` [PATCH 1/3] mm: Don't blindly assign fallback_migrate_page() Richard Weinberger
2016-06-16 23:11 ` Andrew Morton
2016-06-17 7:41 ` Richard Weinberger
2016-06-17 16:28 ` Michal Hocko
2016-06-17 16:55 ` Richard Weinberger [this message]
2016-06-17 18:27 ` Michal Hocko
2016-06-17 19:36 ` Richard Weinberger
2016-06-17 20:03 ` Michal Hocko
2016-06-22 22:21 ` Richard Weinberger
2016-06-16 21:26 ` [PATCH 2/3] mm: Export migrate_page_move_mapping and migrate_page_copy Richard Weinberger
2016-06-16 21:26 ` [PATCH 3/3] UBIFS: Implement ->migratepage() Richard Weinberger
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=57642B91.4020206@nod.at \
--to=richard@nod.at \
--cc=adrian.hunter@intel.com \
--cc=akpm@linux-foundation.org \
--cc=alex@nextthing.co \
--cc=boris.brezillon@free-electrons.com \
--cc=david@fromorbit.com \
--cc=david@sigma-star.at \
--cc=dedekind1@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=hch@infradead.org \
--cc=hughd@google.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-mtd@lists.infradead.org \
--cc=maxime.ripard@free-electrons.com \
--cc=mgorman@techsingularity.net \
--cc=mhocko@kernel.org \
--cc=n-horiguchi@ah.jp.nec.com \
--cc=rvaswani@codeaurora.org \
--cc=sasha.levin@oracle.com \
--cc=shailendra.capricorn@gmail.com \
--cc=tony.luck@intel.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).