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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
