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, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>