Hello, On Mon, Nov 05, 2012 at 03:54:43PM -0800, Arun Sharma wrote: > 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.
I don't get it. How do we create contiguos region by madvise? Just out of curiosity. Could you elaborate that use case? :) > > -Arun > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majord...@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"d...@kvack.org";> em...@kvack.org </a> -- Kind Regards, Minchan Kim -- 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/
