Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440Ab3IJS5e (ORCPT ); Tue, 10 Sep 2013 14:57:34 -0400 Received: from relay2.sgi.com ([192.48.179.30]:41408 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751230Ab3IJS5d (ORCPT ); Tue, 10 Sep 2013 14:57:33 -0400 From: Nathan Zimmer To: mingo@kernel.org, hpa@zytor.com Cc: Robin Holt , Nathan Zimmer , Linux Kernel , Linux MM , Rob Landley , Mike Travis , Daniel J Blueman , Andrew Morton , Greg KH , Yinghai Lu , Mel Gorman Subject: [PATCH] Have __free_pages_memory() free in larger chunks. Date: Tue, 10 Sep 2013 13:57:24 -0500 Message-Id: <1378839444-196190-1-git-send-email-nzimmer@sgi.com> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2743 Lines: 85 From: Robin Holt On large memory machines it can take a few minutes to get through free_all_bootmem(). Currently, when free_all_bootmem() calls __free_pages_memory(), the number of contiguous pages that __free_pages_memory() passes to the buddy allocator is limited to BITS_PER_LONG. BITS_PER_LONG was originally chosen to keep things similar to mm/nobootmem.c. But it is more efficient to limit it to MAX_ORDER. base new change 8TB 202s 172s 30s 16TB 401s 351s 50s That is around 1%-3% improvement on total boot time. This patch was spun off from the boot time rfc Robin and I had been working on. Signed-off-by: Robin Holt Signed-off-by: Nathan Zimmer To: "H. Peter Anvin" To: Ingo Molnar Cc: Linux Kernel Cc: Linux MM Cc: Rob Landley Cc: Mike Travis Cc: Daniel J Blueman Cc: Andrew Morton Cc: Greg KH Cc: Yinghai Lu Cc: Mel Gorman --- mm/nobootmem.c | 25 ++++++++----------------- 1 file changed, 8 insertions(+), 17 deletions(-) diff --git a/mm/nobootmem.c b/mm/nobootmem.c index 61107cf..2c254d3 100644 --- a/mm/nobootmem.c +++ b/mm/nobootmem.c @@ -82,27 +82,18 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size) static void __init __free_pages_memory(unsigned long start, unsigned long end) { - unsigned long i, start_aligned, end_aligned; - int order = ilog2(BITS_PER_LONG); + int order; - start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1); - end_aligned = end & ~(BITS_PER_LONG - 1); + while (start < end) { + order = min(MAX_ORDER - 1UL, __ffs(start)); - if (end_aligned <= start_aligned) { - for (i = start; i < end; i++) - __free_pages_bootmem(pfn_to_page(i), 0); + while (start + (1UL << order) > end) + order--; - return; - } - - for (i = start; i < start_aligned; i++) - __free_pages_bootmem(pfn_to_page(i), 0); + __free_pages_bootmem(pfn_to_page(start), order); - for (i = start_aligned; i < end_aligned; i += BITS_PER_LONG) - __free_pages_bootmem(pfn_to_page(i), order); - - for (i = end_aligned; i < end; i++) - __free_pages_bootmem(pfn_to_page(i), 0); + start += (1UL << order); + } } static unsigned long __init __free_memory_core(phys_addr_t start, -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/