From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753381AbcGVJEo (ORCPT ); Fri, 22 Jul 2016 05:04:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:34472 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753205AbcGVJEm (ORCPT ); Fri, 22 Jul 2016 05:04:42 -0400 From: NeilBrown To: Michal Hocko , linux-mm@kvack.org Date: Fri, 22 Jul 2016 19:04:25 +1000 Cc: Mikulas Patocka , Ondrej Kozina , David Rientjes , Tetsuo Handa , Mel Gorman , Andrew Morton , LKML , dm-devel@redhat.com, Michal Hocko Subject: Re: [RFC PATCH 2/2] mm, mempool: do not throttle PF_LESS_THROTTLE tasks In-Reply-To: <87oa5q5abi.fsf@notabene.neil.brown.name> References: <1468831164-26621-1-git-send-email-mhocko@kernel.org> <1468831285-27242-1-git-send-email-mhocko@kernel.org> <1468831285-27242-2-git-send-email-mhocko@kernel.org> <87oa5q5abi.fsf@notabene.neil.brown.name> User-Agent: Notmuch/0.22 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-suse-linux-gnu) Message-ID: <87lh0u59ie.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain On Fri, Jul 22 2016, NeilBrown wrote: > > Looking at the current code, __GFP_DIRECT_RECLAIM is disabled the first > time through, but if the pool is empty, direct-reclaim is allowed on the > next attempt. Presumably this is where the throttling comes in ?? I > suspect that it really shouldn't do that. It should leave kswapd to do > reclaim (so __GFP_KSWAPD_RECLAIM is appropriate) and only wait in > mempool_alloc where pool->wait can wake it up. Actually, thinking about the kswapd connection, it might make sense for mempool_alloc() to wait in the relevant pgdata->pfmemalloc_wait as well as waiting on pool->wait. What way it should be able to proceed as soon as any memory is available. I don't know what the correct 'pgdata' is though. Just a thought, NeilBrown --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJXkeGZAAoJEDnsnt1WYoG5yg4P/0OUJHSKniG6PislfnPKJR1v WBvPb65TuUQwcZYOQXw072hD1gtT3MrLGSRd/38YmVGZX+0OxO1eVUpwMfwUAIl1 fDKTG8FBDutm/F9TvD3ff6V/0OxAxq32rq8xe45RULu7aIt4mxXMr0WwmAZ1+Lyk 2UdP9c26waHnToDtrz/tf8drLsnWWUWsJGSibPbjH+I5QZQNVdcGnQOpJ5X5LPN6 eWK+WeXblcmRNqBonf33O8h8jLp8c+O2YKD+wUSc50gZYpa0tjgWgy27vvcr7zpO lSVY4mOLI+t2qbp2Vz27NqxgppSyeveKHa664/WMnyvkz2rk7ZsrL+zDR2oID/+A /r4vHqklNga1zAbf5nBotBZJQtLWRpfPNZU8l82cFeMlmSoDvHTL1aIRBcKOMpzX VWqLyGOkZ5TiOjxAzSgqwaLErj6kIYzzRtfTADuX3BmrBv0CYkuVsjNHskRSjOsC whk8kwx6j+lXxuuNKry6Ft1su4qj0SWU3hVcTm9shc5lGRqFc76pAIJFY3SF1/Ru PQpcuFK49t66woOJvpsYUl69ly5cdmxWUEVjs4n8YkA7kTdK5P02BqzmXbZW6zNE WcijXYHTCqZPAJyV1u6PUTjSym3sAgz28FdQnrDUzmpn6Y8GVk28FnAF8vRDA4d1 YSfjZY2EKbJDUOOumsqY =bNio -----END PGP SIGNATURE----- --=-=-=--