From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 7/7] x86: ensure percpu lpage doesn't consume too much vmalloc space Date: Wed, 17 Jun 2009 12:52:19 +0900 Message-ID: <1245210739-25699-8-git-send-email-tj@kernel.org> References: <1245210739-25699-1-git-send-email-tj@kernel.org> Return-path: Received: from hera.kernel.org ([140.211.167.34]:49533 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764370AbZFQDxD (ORCPT ); Tue, 16 Jun 2009 23:53:03 -0400 In-Reply-To: <1245210739-25699-1-git-send-email-tj@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, mingo@elte.hu, JBeulich@novell.com, andi@firstfloor.org, hpa@zytor.com, tglx@linutronix.de Cc: Tejun Heo On extreme configuration (e.g. 32bit 32-way NUMA machine), lpage percpu first chunk allocator can consume too much of vmalloc space. Make it fall back to 4k allocator if the consumption goes over 20%. [ Impact: add sanity check for lpage percpu first chunk allocator ] Signed-off-by: Tejun Heo Reported-by: Jan Beulich Cc: Andi Kleen Cc: Ingo Molnar --- arch/x86/kernel/setup_percpu.c | 18 +++++++++++++++--- 1 files changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 165ebd5..29a3eef 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -163,9 +163,21 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen) int i, j; ssize_t ret; - /* on non-NUMA, embedding is better */ - if (!chosen && !pcpu_need_numa()) - return -EINVAL; + if (!chosen) { + size_t vm_size = VMALLOC_END - VMALLOC_START; + size_t tot_size = num_possible_cpus() * PMD_SIZE; + + /* on non-NUMA, embedding is better */ + if (!pcpu_need_numa()) + return -EINVAL; + + /* don't consume more than 20% of vmalloc area */ + if (tot_size > vm_size / 5) { + pr_info("PERCPU: too large chunk size %zuMB for " + "large page remap\n", tot_size >> 20); + return -EINVAL; + } + } /* need PSE */ if (!cpu_has_pse) { -- 1.6.0.2