From 127493d5dc73589cbe00ea5ec8357cc2a4c0d82a Mon Sep 17 00:00:00 2001
From: Nishanth Aravamudan <nacc@us.ibm.com>
Date: Wed, 13 Apr 2011 19:45:59 +0000
Subject: [PATCH] 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/platforms/pseries/setup.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 000724149089..6c42cfde8415 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -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);
--
GitLab