Re: [PATCH 2/4] kmemleak: Handle percpu memory allocation

[Tejun Heo <htejun@gmail.com>]

Hello,

On Tue, Oct 04, 2011 at 10:04:46AM +0100, Catalin Marinas wrote:
> > The percpu part looks fine to me but I don't know how kmemleak works
> > to judge whether the kmemleak part is okay or not.  This just avoids
> > false positives from slab and would still require bumping up the early
> > log memory as # of cpus increases, right?
> 
> No, there is only one kmemleak call for each __percpu pointer (to the
> specific kmemleak_*_percpu function). The kmemleak expands the percpu
> pointer into corresponding blocks for each cpu but the early log only
> stores a single call.

Hmmm... but the following definitely seems O(#PCPU_ALLOCS * #CPUS)?
What am I missing?

+/*
+ * Log an early allocated block and populate the stack trace.
+ */
+static void early_alloc_percpu(struct early_log *log)
+{
+       unsigned int cpu;
+       const void __percpu *ptr = log->ptr;
+
+       for_each_possible_cpu(cpu) {
+               log->ptr = per_cpu_ptr(ptr, cpu);
+               early_alloc(log);
+       }
+}

Thanks.

-- 
tejun