Date: Sat, 13 Oct 2012 00:15:38 +0200 From: Jilles Tjoelker <jilles@stack.nl> To: John Baldwin <jhb@freebsd.org> Cc: Marcel Moolenaar <marcel@xcllnt.net>, freebsd-arch@freebsd.org Subject: Re: mmap and resource limits Message-ID: <20121012221538.GA96422@stack.nl> In-Reply-To: <201210121338.28956.jhb@freebsd.org> References: <83AE27A6-C844-4720-99E7-A12106F77227@xcllnt.net> <FD8885CC-6E66-435A-A858-82F41B0F239D@xcllnt.net> <201210121338.28956.jhb@freebsd.org>
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On Fri, Oct 12, 2012 at 01:38:28PM -0400, John Baldwin wrote: > On Friday, October 12, 2012 12:04:19 pm Marcel Moolenaar wrote: > > On Oct 8, 2012, at 10:40 AM, Marcel Moolenaar <marcel@xcllnt.net> wrote: > > > What's the progress of mmap(2) doing resource accounting and > > > it respecting resource limits? > > *silence* > > Ok, so no new progress. We're still not doing it and we don't > > have an idea of how we want to do it if or when we're going to > > want to do it. Consequently: we still need brk()/sbrk(). > > Correct assessment? > Well. You can use RLIMIT_AS, but that includes anything you map, not > just malloc(). This is effective for many applications. I have found it particularly useful against runaway memory leaks in applications moved from 32-bit to 64-bit systems. > The problem is that even if you use sbrk() and rely on RLIMIT_DATA, > any misbehaving app can just use mmap(MAP_ANON) or shm_open() to get > around that. As of 8.0 it is possible to enable swap accounting to limit anonymous memory. This uses the vm.overcommit sysctl and RLIMIT_SWAP rlimit described in tuning(7). For example: # sysctl vm.overcommit=2 $ ulimit -w 100000 The rlimit limits the total for the UID (much like RLIMIT_NPROC, RLIMIT_SBSIZE and RLIMIT_NPTS). -- Jilles Tjoelker
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