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Commit 127493d5 authored by Nishanth Aravamudan's avatar Nishanth Aravamudan Committed by Benjamin Herrenschmidt
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powerpc/pseries: Use a kmem cache for DTL buffers 



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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 7c7a81b5

arch/powerpc/platforms/pseries/setup.c

+10 −2
Original line number Diff line number Diff line
@@ -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);