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| author | Tejun Heo <tj@kernel.org> | 2009-06-22 04:56:24 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2009-06-22 04:56:24 +0200 |
| commit | 0017c869ddcb73069905d09f9e98e68627466237 (patch) | |
| tree | 380248938561c53ff174ffba72f22cbc3e8a5438 /arch/x86/kernel/setup_percpu.c | |
| parent | x86: implement percpu_alloc kernel parameter (diff) | |
| download | linux-0017c869ddcb73069905d09f9e98e68627466237.tar.xz linux-0017c869ddcb73069905d09f9e98e68627466237.zip | |
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 <tj@kernel.org>
Reported-by: Jan Beulich <JBeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/setup_percpu.c')
| -rw-r--r-- | 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 165ebd5ba83b..29a3eef7cf4a 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) { |