Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752641AbaKDIbV (ORCPT ); Tue, 4 Nov 2014 03:31:21 -0500 Received: from numascale.com ([213.162.240.84]:50545 "EHLO numascale.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752567AbaKDIbR (ORCPT ); Tue, 4 Nov 2014 03:31:17 -0500 From: Daniel J Blueman To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Bjorn Helgaas Cc: Daniel J Blueman , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Steffen Persvold Subject: [PATCH v4 4/4] Use 2GB memory block size on large-memory x86-64 systems Date: Tue, 4 Nov 2014 16:29:44 +0800 Message-Id: <1415089784-28779-4-git-send-email-daniel@numascale.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1415089784-28779-1-git-send-email-daniel@numascale.com> References: <1415089784-28779-1-git-send-email-daniel@numascale.com> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cpanel21.proisp.no X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - numascale.com X-Get-Message-Sender-Via: cpanel21.proisp.no: authenticated_id: daniel@numascale.com X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On large-memory x86-64 systems of 64GB or more with memory hot-plug enabled, use a 2GB memory block size. Eg with 64GB memory, this reduces the number of directories in /sys/devices/system/memory from 512 to 32, making it more manageable, and reducing the creation time accordingly. This caveat is that the memory can't be offlined (for hotplug or otherwise) with finer 128MB granularity, but this is unimportant due to the high memory densities generally used with such large-memory systems, where eg a single DIMM is the order of 16GB. Signed-off-by: Daniel J Blueman --- init_64.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a992..9622ab2 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -52,7 +52,6 @@ #include #include #include -#include #include #include "mm_internal.h" @@ -1234,12 +1233,10 @@ static unsigned long probe_memory_block_size(void) /* start from 2g */ unsigned long bz = 1UL<<31; -#ifdef CONFIG_X86_UV - if (is_uv_system()) { - printk(KERN_INFO "UV: memory block size 2GB\n"); + if (totalram_pages >= (64ULL << (30 - PAGE_SHIFT))) { + pr_info("Using 2GB memory block size for large-memory system\n"); return 2UL * 1024 * 1024 * 1024; } -#endif /* less than 64g installed */ if ((max_pfn << PAGE_SHIFT) < (16UL << 32)) -- 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/