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powerpc/pseries: Use a kmem cache for DTL buffers

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PAPR specifies that DTL buffers can not cross AMS environments (aka CMO
in the PAPR) and can not cross a memory entitlement granule boundary
(4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR.
kmalloc does not guarantee an alignment of the allocation, though,
beyond 8 bytes (at least in my understanding). Create a special kmem
cache for DTL buffers with the alignment requirement.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nishanth Aravamudan 2011-04-13 19:45:59 +00:00 committed by Benjamin Herrenschmidt
parent 7c7a81b53e
commit 127493d5dc
1 changed files with 10 additions and 2 deletions
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12
arch/powerpc/platforms/pseries/setup.c
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@ -287,14 +287,22 @@ static int alloc_dispatch_logs(void)
int cpu, ret;
struct paca_struct *pp;
struct dtl_entry *dtl;
struct kmem_cache *dtl_cache;
if (!firmware_has_feature(FW_FEATURE_SPLPAR))
return 0;
dtl_cache = kmem_cache_create("dtl", DISPATCH_LOG_BYTES,
DISPATCH_LOG_BYTES, 0, NULL);
if (!dtl_cache) {
pr_warn("Failed to create dispatch trace log buffer cache\n");
pr_warn("Stolen time statistics will be unreliable\n");
return 0;
}
for_each_possible_cpu(cpu) {
pp = &paca[cpu];
dtl = kmalloc_node(DISPATCH_LOG_BYTES, GFP_KERNEL,
cpu_to_node(cpu));
dtl = kmem_cache_alloc(dtl_cache, GFP_KERNEL);
if (!dtl) {
pr_warn("Failed to allocate dispatch trace log for cpu %d\n",
cpu);