Messages in this thread | | | Date | Mon, 5 Nov 2012 15:54:43 -0800 | From | Arun Sharma <> | Subject | Re: [RFC v2] Support volatile range for anon vma |
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On Wed, Oct 31, 2012 at 06:56:05PM -0400, KOSAKI Motohiro wrote: > glibc malloc discard freed memory by using MADV_DONTNEED > as tcmalloc. and it is often a source of large performance decrease. > because of MADV_DONTNEED discard memory immediately and > right after malloc() call fall into page fault and pagesize memset() path. > then, using DONTNEED increased zero fill and cache miss rate.
The memcg based solution that I posted a few months ago is working well for us. We see significantly less cpu in zero'ing pages.
Not everyone was comfortable with the security implications of recycling pages between processes in a memcg, although it was disabled by default and had to be explicitly opted-in.
Also, memory allocators have a second motivation in using madvise: to create virtually contiguous regions of memory from a fragmented address space, without increasing the RSS.
-Arun
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