[patch] Avoid duplicate string allocations for the same cpu type
If a system has more than one cpu type, get_model_name() will
allocate a unique "model name" string for each cpu different than
the boot cpu. (See "model name" in /proc/cpuinfo for an example.)
What compounds this is Intel's decision to give different steppings
different model names. Montecito C1 is
"Dual-Core Intel(R) Itanium(R) 2 Processor 9040" while Montecito C2 is
"Dual-Core Intel(R) Itanium(R) 2 Processor 9050". That increases the
likelyhood of having different cpu types.
Model names are also getting longer, such as
"Intel(r) Itanium(r) 2 Processor 1.6GHz with 18M L3 Cache for 533MHz Platforms".
Each thread is treated as a different "cpu", further compounding the problem.
This patch makes get_model_name() smarter. It allocates one string
for each unique "model name" and returns a pointer to the appropriate
string. It handles up to 8 different cpu types. Above that number
it reverts to the previous behavior of allocating a unque string for each
thread. Since all threads in a socket have the same "model name", there
needs to be more than 8 different socket types to revert to the old behavior.
Signed-off-by: Russ Anderson (rja@xxxxxxx)
---
arch/ia64/kernel/setup.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
Index: test/arch/ia64/kernel/setup.c
===================================================================
--- test.orig/arch/ia64/kernel/setup.c 2007-03-09 17:32:27.000000000 -0600
+++ test/arch/ia64/kernel/setup.c 2007-03-10 16:06:04.313548208 -0600
@@ -665,11 +665,14 @@ struct seq_operations cpuinfo_op = {
};
static char brandname[128];
+#define BRAND_SIZE 8
+static char * brands[BRAND_SIZE];
static char * __cpuinit
get_model_name(__u8 family, __u8 model)
{
char brand[128];
+ int i;
memcpy(brand, "Unknown", 8);
if (ia64_pal_get_brand_info(brand)) {
@@ -681,12 +684,24 @@ get_model_name(__u8 family, __u8 model)
case 2: memcpy(brand, "Madison up to 9M cache", 23); break;
}
}
- if (brandname[0] == '\0')
- return strcpy(brandname, brand);
- else if (strcmp(brandname, brand) == 0)
- return brandname;
- else
- return kstrdup(brand, GFP_KERNEL);
+ /*
+ * kstrdup() cannot be called early in the boot process,
+ * so use a static buffer for the first cpu.
+ */
+ if (!brands[0]) {
+ strcpy(brandname, brand);
+ brands[0] = brandname;
+ return brands[0];
+ }
+ for (i = 0; i < BRAND_SIZE; i++) {
+ if (!brands[i]) {
+ brands[i] = kstrdup(brand, GFP_KERNEL);
+ return brands[i];
+ } else if (strcmp(brands[i], brand) == 0) {
+ return brands[i];
+ }
+ }
+ return kstrdup(brand, GFP_KERNEL);
}
static void __cpuinit
--
Russ Anderson, OS RAS/Partitioning Project Lead
SGI - Silicon Graphics Inc rja@xxxxxxx
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