Date: Thu, 26 Mar 2015 22:58:54 -0400 From: J David <j.david.lists@gmail.com> To: Steven Hartland <killing@multiplay.co.uk>, "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Significant memory leak in 9.3p10? Message-ID: <CABXB=RR0sd1-HUq7%2BfMde38dzPTMLZwWWgV1orG6ousu4=sz6w@mail.gmail.com> In-Reply-To: <5514B220.6080308@multiplay.co.uk> References: <CABXB=RRhynY5FWvw3tHrLFRyitTemavXYLBpev5Mjs_kPqimXA@mail.gmail.com> <20150316232404.GM2379@kib.kiev.ua> <CABXB=RSt0MgEyoJs4o5utTg7oSu0RZ%2B-czeY0k-Ro%2BfRubK3kQ@mail.gmail.com> <CABXB=RTe9d0DD68RCi6JWKH%2BcK%2Ba8McmKmeejTypLhVZRc0t7w@mail.gmail.com> <CAN6yY1si_6KRXrTdXABGdtAfqRcCyqqe48acbVUmRT1eZ7tuXw@mail.gmail.com> <CABXB=RRsF4RoMiVA88WeAgXoYQihU8s2g3T=ToO3HW9DceroKw@mail.gmail.com> <5514B220.6080308@multiplay.co.uk>
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On Thu, Mar 26, 2015 at 9:28 PM, Steven Hartland <killing@multiplay.co.uk> wrote: > Does vmstat -m or vmstat -z shed any light? None, as those show kernel memory usage, not user space. Looking at them anyway shows nothing unusual, consuming large amounts of memory, or disproportionate to the kernel memory shown as in-use. The list of suspects that can consume user memory without being associated with any user process is very short: some sort of anonymous, persistent shared memory object. Konstantin offered a partial list of some likely candidates in response to the initial message, including: - NO: tmpfs mounts (not used) - NO: swap-backed md disks (not used) - PROBABLY NO: sysv shared memory (believed not to be used) - MAYBE: possibly posix shared memory (unknown whether used) - MAYBE: anonymous mmap segments that have somehow got lost (i.e. file descriptor is hanging around in the kernel somewhere) -- proposed by someone off-list - MAYBE: others? Of the two remaining known possibilities, posix shared memory seems more likely than an unknown mmap bug. Unfortunately, I have not found any way to gather statistics and/or get/set limits on posix shared memory usage. Does such a method exist? Really, it would be great if there were a tool that could walk the entire list of VM blocks and generate some kind of report or statistics (like vmstat -z or vmstat -m, but for VM rather than kernel memory). As it is, we are reduced to guessing what might be going on, which is decidedly suboptimal. However, I have no idea if such a tool exists, if it is even possible to write, or (if it is) how to go about writing it. Thanks!
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