linux-kernel - Re: long sleep_on_page delays writing to slow storage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 14 Nov 2011 13:47:17 -0500
From:	Dave Jones <davej@...hat.com>
To:	Johannes Weiner <jweiner@...hat.com>
Cc:	Andrea Arcangeli <aarcange@...hat.com>,
	Mel Gorman <mgorman@...e.de>, Jan Kara <jack@...e.cz>,
	Andy Isaacson <adi@...apodia.org>,
	linux-kernel@...r.kernel.org, linux-mm@...r.kernel.org,
	kernel-team@...oraproject.org
Subject: Re: long sleep_on_page delays writing to slow storage

On Thu, Nov 10, 2011 at 10:34:42AM +0100, Johannes Weiner wrote:
 
 > > I wonder if a change like this would be enough?
 > > 
 > >        sync_migration = !(gfp_mask & __GFP_NO_KSWAPD);
 > > 
 > > But even if hidden in a new function, the main downside overall is the
 > > fact we'll pass one more var through the stack of fast paths.
 > > 
 > > Johannes I recall you reported this too and Mel suggested the above
 > > change, did it help in the end?
 > 
 > Yes, it completely fixed the latency problem.
 > 
 > That said, I haven't looked at the impact on the THP success rate, but
 > a regression there is probably less severe than half-minute-stalls in
 > interactive applications.

FWIW, we've had a few reports from Fedora users since we moved to 3.x kernels
about similar problems, so whatever the fix is for this should probably
go to stable too.

I could push an update for Fedora users to test the change above if
that would be helpful ?

	Dave

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/