Date: Sun, 9 Oct 2016 15:09:53 +0200 From: Eduardo Morras <emorrasg@yahoo.es> To: freebsd-questions@freebsd.org Subject: Re: Swap exhaustion Message-ID: <20161009150953.8bb8fee6360710c4eb54c945@yahoo.es> In-Reply-To: <9DB5B54C-2AE4-4200-AB78-F86913E1E433@mail.sermon-archive.info> References: <1CD13C1C-5344-4909-A061-F25FBB86AFF9@lafn.org> <9DB5B54C-2AE4-4200-AB78-F86913E1E433@mail.sermon-archive.info>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 8 Oct 2016 18:33:47 -0700 Doug Hardie <doug@mail.sermon-archive.info> wrote: > > > On 27 May 2015, at 16:49, Doug Hardie <bc979@lafn.org> wrote: > > > > I have a process that is eating up 6 GB of swap space. At that > > point, FreeBSD 9.3 terminates a process. However, occasionally its > > not the one eating up the space. When I manually quit the process > > then the swap space returns to a few KB used. The system runs fine > > after that. > > > > I have very little knowledge of what this process is doing > > internally but would like to know what might be causing this > > issue. There are 5 of these processes running (parent plus 4 > > children). Normally each uses about 90 MB RES/SIZE. However when > > the problem occurs they are about 2GB RES/SIZE each. The system > > has 4 GB memory. I thought that a malloc would not be able to grab > > that much memory, even with swapping as it has to be in memory. > > Could a malloc cause this growth in process size or need I look > > elsewhere? > > I have been trying periodically to resolve this issue. I modified > the application to log (syslog) every memory location it allocates. > Interestingly enough they are all around 0x100F380. However, the > segments that are increasing in number all have the highest order > address bit set, i.e., 0x83ac00000. These are shown by procstat as > type "df". The number of these increases with time. The sizes vary > from what appears to be small to over 5000 resident pages. They > never seem to go away unless I restart the process. Right after a > restart there are 7 "df"s. However, with time there can eventually > be hundreds. Since these do not have any file backing them, they eat > up swap space and thus cause the system to run out of swap and start > killing processes. > > What things allocate memory at the top of the address space? The > application mallocs and mmaps all allocate much lower in the address > space. FreeBSD 9.3 uses (afair) jemalloc 3.4. There are tons of bug fixes in newer versions, last one 4.2.1. Perhaps you were bitten by one. There is not a port :( but compiles nicely under FreeBSD 10.3 (don't tried under 9.3). https://github.com/jemalloc/jemalloc/blob/dev/ChangeLog http://jemalloc.net/ --- --- Eduardo Morras <emorrasg@yahoo.es>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20161009150953.8bb8fee6360710c4eb54c945>