From owner-svn-src-all@freebsd.org Wed Nov 21 00:58:42 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C85B411446ED; Wed, 21 Nov 2018 00:58:41 +0000 (UTC) (envelope-from bwidawsk@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1C69B8D6C6; Wed, 21 Nov 2018 00:58:40 +0000 (UTC) (envelope-from bwidawsk@freebsd.org) Received: from smtp.freebsd.org (c-73-25-164-31.hsd1.or.comcast.net [73.25.164.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) (Authenticated sender: bwidawsk) by smtp.freebsd.org (Postfix) with ESMTPSA id 089061E16D; Wed, 21 Nov 2018 00:58:35 +0000 (UTC) (envelope-from bwidawsk@freebsd.org) Date: Tue, 20 Nov 2018 16:58:32 -0800 From: Ben Widawsky To: Mark Johnston Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r340709 - in head/sys: compat/linuxkpi/common/include/linux vm Message-ID: <20181121005832.ongabjesxlsd7cqu@smtp.freebsd.org> Mail-Followup-To: Mark Johnston , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201811202249.wAKMnJxH082469@repo.freebsd.org> <20181121003515.GE2630@raichu> <20181121004239.spk72g2pikvse4y7@smtp.freebsd.org> <20181121005148.GF2630@raichu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181121005148.GF2630@raichu> User-Agent: NeoMutt/20180716 X-Rspamd-Queue-Id: 1C69B8D6C6 X-Spamd-Result: default: False [0.76 / 15.00]; local_wl_from(0.00)[freebsd.org]; NEURAL_SPAM_MEDIUM(0.18)[0.180,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US]; NEURAL_SPAM_SHORT(0.76)[0.760,0]; NEURAL_HAM_LONG(-0.18)[-0.182,0] X-Rspamd-Server: mx1.freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Nov 2018 00:58:42 -0000 On 18-11-20 19:51:48, Mark Johnston wrote: > On Tue, Nov 20, 2018 at 04:42:39PM -0800, Ben Widawsky wrote: > > On 18-11-20 19:35:15, Mark Johnston wrote: > > > On Tue, Nov 20, 2018 at 10:49:19PM +0000, Ben Widawsky wrote: > > > > Author: bwidawsk > > > > Date: Tue Nov 20 22:49:19 2018 > > > > New Revision: 340709 > > > > URL: https://svnweb.freebsd.org/changeset/base/340709 > > > > > > > > Log: > > > > linuxkpi: Add some basic swap functions > > > > > > > > These are used by kms-drm to determine various heuristics relate > > > > memory conditions. > > > > > > > > The number of free swap pages is just a variable, and it can be > > > > much cheaper by either adding a new getter, or simply extern'ing > > > > swap_total. However, this patch opts to use the more expensive, > > > > existing interface - since this isn't an operation in a high per > > > > path. > > > > > > > > This allows us to remove some more gpl linuxkpi and do the follo > > > > kms-drm: > > > > git rm linuxkpi/gplv2/include/linux/swap.h > > > > > > > > Reviewed by: mmacy, Johannes Lundberg > > > > Approved by: emaste (mentor) > > > > Differential Revision: https://reviews.freebsd.org/D18052 > > > > > > > > Added: > > > > head/sys/compat/linuxkpi/common/include/linux/swap.h (contents, props changed) > > > > Modified: > > > > head/sys/vm/vm_pageout.h > > > > head/sys/vm/vm_swapout.c > > > > > > > > [...] > > > > Modified: head/sys/vm/vm_swapout.c > > > > ============================================================================== > > > > --- head/sys/vm/vm_swapout.c Tue Nov 20 22:24:18 2018 (r340708) > > > > +++ head/sys/vm/vm_swapout.c Tue Nov 20 22:49:19 2018 (r340709) > > > > @@ -961,3 +961,10 @@ swapout(struct proc *p) > > > > p->p_swtick = ticks; > > > > return (0); > > > > } > > > > + > > > > +/* Used to determine if the current process is itself the reaper. */ > > > > +bool > > > > +vm_curproc_is_vmproc(void) > > > > +{ > > > > + return curproc == vmproc; > > > > +} > > > > > > From a look at how this is used, it should probably be pageproc rather > > > than vmproc. There are various code paths that just check > > > curproc == pageproc inline. > > > > > > > Could I trouble you for a quick explanation of the difference between the two? > > pageproc contains the page daemon and laundry threads, which are > responsible for managing the LRU page queues and writing back dirty > pages. vmproc's main task is to swap out kernel stacks when the system > is under memory pressure, and swap them back in when necessary. It's a > somewhat legacy component of the system and isn't required. You can > build a kernel without it by specifying "options NO_SWAPPING" (which is > a somewhat misleading name), in which vm_swapout_dummy.c is compiled > instead of vm_swapout.c. > Thanks for the explanation. I indeed want the page daemon. I will put up a patch to do that the correct way. Thanks.