Date: Wed, 22 Aug 2012 14:01:05 +0200 From: Luigi Rizzo <rizzo@iet.unipi.it> To: current@freebsd.org Subject: less aggressive contigmalloc ? Message-ID: <20120822120105.GA63763@onelab2.iet.unipi.it>
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I am trying to make netmap adapt the amount of memory it allocates to what is available. At its core, it uses contigmalloc() with small chunks (even down to 1 page) to fetch memory. Problem is, i notice that before failing, contigmalloc() tries to swap out some processes (effectively killing them because i have no swap configured in my picobsd image). This happens with both M_WAITOK and M_NOWAIT, the difference is only in the number of retries it does -- see e.g. sys/vm/vm_kern.c :: kmem_alloc_contig() where it retries once for M_NOWAIT and 3 times for M_WAITOK. I wonder if there is a way to make contigmalloc less aggressive and fail without killing those innocent processes ? cheers luigi
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