From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx118.postini.com [74.125.245.118]) by kanga.kvack.org (Postfix) with SMTP id 5B0946B0002 for ; Mon, 18 Feb 2013 16:59:44 -0500 (EST) MIME-Version: 1.0 Message-ID: <2c81050d-72b0-4a93-aecb-900171a019d0@default> Date: Mon, 18 Feb 2013 13:59:25 -0800 (PST) From: Dan Magenheimer Subject: RE: [PATCHv5 4/8] zswap: add to mm/ References: <1360780731-11708-1-git-send-email-sjenning@linux.vnet.ibm.com> <1360780731-11708-5-git-send-email-sjenning@linux.vnet.ibm.com> <511F0536.5030802@gmail.com> <51227FDA.7040000@linux.vnet.ibm.com> <0fb2af92-575f-4f5d-a115-829a3cf035e5@default> <5122918A.8090307@linux.vnet.ibm.com> In-Reply-To: <5122918A.8090307@linux.vnet.ibm.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Seth Jennings Cc: Ric Mason , Andrew Morton , Greg Kroah-Hartman , Nitin Gupta , Minchan Kim , Konrad Wilk , Robert Jennings , Jenifer Hopper , Mel Gorman , Johannes Weiner , Rik van Riel , Larry Woodman , Benjamin Herrenschmidt , Dave Hansen , Joe Perches , linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org > From: Seth Jennings [mailto:sjenning@linux.vnet.ibm.com] > Subject: Re: [PATCHv5 4/8] zswap: add to mm/ >=20 > On 02/18/2013 01:55 PM, Dan Magenheimer wrote: > >> From: Seth Jennings [mailto:sjenning@linux.vnet.ibm.com] > >> Subject: Re: [PATCHv5 4/8] zswap: add to mm/ > >> > >> On 02/15/2013 10:04 PM, Ric Mason wrote: > >>>> + * certain event is occurring. > >>>> +*/ > >>>> +static u64 zswap_pool_limit_hit; > >>>> +static u64 zswap_reject_compress_poor; > >>>> +static u64 zswap_reject_zsmalloc_fail; > >>>> +static u64 zswap_reject_kmemcache_fail; > >>>> +static u64 zswap_duplicate_entry; > >>>> + > >>>> +/********************************* > >>>> +* tunables > >>>> +**********************************/ > >>>> +/* Enable/disable zswap (disabled by default, fixed at boot for > >>>> now) */ > >>>> +static bool zswap_enabled; > >>>> +module_param_named(enabled, zswap_enabled, bool, 0); > >>> > >>> please document in Documentation/kernel-parameters.txt. > >> > >> Will do. > > > > Is that a good idea? Konrad's frontswap/cleancache patches > > to fix frontswap/cleancache initialization so that backends > > can be built/loaded as modules may be merged for 3.9. > > AFAIK, module parameters are not included in kernel-parameters.txt. >=20 > This is true. However, the frontswap/cleancache init stuff isn't the > only reason zswap is built-in only. The writeback code depends on > non-exported kernel symbols: >=20 > swapcache_free > __swap_writepage > __add_to_swap_cache > swapcache_prepare > swapper_space > end_swap_bio_write >=20 > I know a fix is as trivial as exporting them, but I didn't want to > take on that debate right now. Hmmm... I wonder if exporting these might be the best solution as it (unnecessarily?) exposes some swap subsystem internals. I wonder if a small change to read_swap_cache_async might be more acceptable. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org