On 02/11/2015 10:03 PM, Ebru Akagunduz wrote: > This patch improves THP collapse rates, by allowing zero pages. > > Currently THP can collapse 4kB pages into a THP when there > are up to khugepaged_max_ptes_none pte_none ptes in a 2MB > range. This patch counts pte none and mapped zero pages > with the same variable. > > The patch was tested with a program that allocates 800MB of > memory, and performs interleaved reads and writes, in a pattern > that causes some 2MB areas to first see read accesses, resulting > in the zero pfn being mapped there. > > To simulate memory fragmentation at allocation time, I modified > do_huge_pmd_anonymous_page to return VM_FAULT_FALLBACK for read > faults. > > Without the patch, only %50 of the program was collapsed into > THP and the percentage did not increase over time. > > With this patch after 10 minutes of waiting khugepaged had > collapsed %99 of the program's memory. > > Signed-off-by: Ebru Akagunduz <ebru.akagun...@gmail.com> > Reviewed-by: Rik van Riel <r...@redhat.com>
Acked-by: Vlastimil Babka <vba...@suse.cz> -- 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/
