Date: Fri, 21 Feb 2014 17:02:16 +0400 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: jeff@freebsd.org, freebsd-stable@freebsd.org, Ronald Klop <ronald-lists@klop.ws> Subject: Re: Processes are incorrectly marked as swapped out Message-ID: <DB219A6F-EFA9-46B9-BA18-CE17A4F0D210@gmail.com> In-Reply-To: <201401281142.10317.jhb@freebsd.org> References: <2D47B79E-C171-4B91-B0AB-4DD2212770C6@gmail.com> <op.w9446fkykndu52@ronaldradial.radialsg.local> <201401281142.10317.jhb@freebsd.org>
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On 28 янв. 2014 г., at 20:42, John Baldwin <jhb@freebsd.org> wrote: > On Thursday, January 23, 2014 8:02:29 am Ronald Klop wrote: >> On Thu, 23 Jan 2014 13:19:36 +0100, Dmitry Sivachenko >> <trtrmitya@gmail.com> wrote: >> >>> Hello! >>> >>> After upgrade from stable/9 to stable/10 I see the following regression. >>> Some processes are marked as swapped out in top(1) output: >>> >>> 1436 root 1 43 0 16524K 0K nanslp 14 1:14 0.00% >>> <cron> >>> 1381 smmsp 1 20 0 23988K 0K pause 18 0:04 0.00% >>> <sendma >>> 99348 mitya 1 21 0 23492K 0K pause 16 0:00 0.00% >>> <csh> >>> >>> ps(1) also shows them as swapped out (W as second character in state >>> field): >>> 1381 - IWs 0:00.00 sendmail: Queue runner at 00:30:00 for >>> /var/spool/clie >>> 1436 - IWs 0:00.00 /usr/sbin/cron -s >>> 80231 - IWs 0:00.00 /usr/local/sbin/collectdmon -c >>> /usr/local/sbin/coll >>> 99348 1 IWs 0:00.00 -csh (csh) >>> >>> Though swapinfo reports that zero swap is used and even if I turn swap >>> completely off (swapoff -a) >>> the output of both top(1) and ps(1) does not change: these processes are >>> still marked as swapped out. >> >> The code of an application can get removed from memory, because there >> still is an image of it in the executable on disk. It can be 'swapped' in >> by reading the executable again. The program is memory mapped (mmap). >> See VN PAGER vs SWAP PAGER in 'systat -vm'. > > However, a swapped out process always uses swap (for kernel stacks), so this > seems like a real bug. > Okay, I found a buggy commit: Author: jeff Date: Tue Aug 13 21:56:16 2013 New Revision: 254304 URL: http://svnweb.freebsd.org/changeset/base/254304 Log: Improve pageout flow control to wakeup more frequently and do less work while maintaining better LRU of active pages. <...> Reviewed by: alc (slight variant of this) Discussed with: alc, kib, jhb How do I reproduce the problem: I have a desktop with 2GB of RAM and 4GB of swap space configured. After "make -j 4 buildworld" I see some processes are swapped out (sometimes swapinfo reports swap is not used, sometimes it is used but after swapoff -a those processes are still in swapped out state). I hope this will help to narrow down the problem. Thanks.help
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