From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id A14926B0002 for ; Mon, 18 Feb 2013 15:40:05 -0500 (EST) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 18 Feb 2013 15:40:03 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 4561638C801A for ; Mon, 18 Feb 2013 15:39:42 -0500 (EST) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r1IKdf5U306770 for ; Mon, 18 Feb 2013 15:39:41 -0500 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r1IKdeXk030405 for ; Mon, 18 Feb 2013 15:39:41 -0500 Message-ID: <5122918A.8090307@linux.vnet.ibm.com> Date: Mon, 18 Feb 2013 14:39:38 -0600 From: Seth Jennings MIME-Version: 1.0 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> In-Reply-To: <0fb2af92-575f-4f5d-a115-829a3cf035e5@default> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Magenheimer 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 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: >>> On 02/14/2013 02:38 AM, Seth Jennings wrote: >> >>>> + * The statistics below are not protected from concurrent access for >>>> + * performance reasons so they may not be a 100% accurate. However, >>>> + * the do provide useful information on roughly how many times a >>> >>> s/the/they >> >> Ah yes, thanks :) >> >>> >>>> + * 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. 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: swapcache_free __swap_writepage __add_to_swap_cache swapcache_prepare swapper_space end_swap_bio_write I know a fix is as trivial as exporting them, but I didn't want to take on that debate right now. Seth -- 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