From 0017c869ddcb73069905d09f9e98e68627466237 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 22 Jun 2009 11:56:24 +0900 Subject: x86: ensure percpu lpage doesn't consume too much vmalloc space 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 file changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 165ebd5ba83..29a3eef7cf4 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) { -- cgit v1.2.3