[PATCH 7/7] x86: ensure percpu lpage doesn't consume too much vmalloc space
From: Tejun Heo <tj@kernel.org>
Date: 2009-06-17 03:54:54
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <tj@kernel.org> Reported-by: Jan Beulich <redacted> Cc: Andi Kleen <redacted> Cc: Ingo Molnar <redacted> --- 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) {
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1.6.0.2