[patch] Inline vm_acct_memory

Ravikiran G Thirumalai (kiran@in.ibm.com)
Wed, 28 May 2003 16:35:53 +0530


Hi Andrew,
I found that inlining vm_acct_memory speeds up vm_enough_memory.
Since vm_acct_memory is only called by vm_enough_memory,
theoritically inlining should help, and my tests proved so -- there was
an improvement of about 10 % in profile ticks (vm_enough_memory) on a
4 processor PIII Xeon running kernbench. Here is the patch. Tested on 2.5.70

Thanks,
Kiran

D:
D: Patch inlines use of vm_acct_memory
D:

diff -ruN -X dontdiff linux-2.5.69/include/linux/mman.h linux-2.5.69-vm_acct_inline/include/linux/mman.h
--- linux-2.5.69/include/linux/mman.h Mon May 5 05:23:02 2003
+++ linux-2.5.69-vm_acct_inline/include/linux/mman.h Tue May 20 12:18:34 2003
@@ -2,6 +2,8 @@
#define _LINUX_MMAN_H

#include <linux/config.h>
+#include <linux/smp.h>
+#include <linux/percpu.h>

#include <asm/atomic.h>
#include <asm/mman.h>
@@ -13,7 +15,27 @@
extern atomic_t vm_committed_space;

#ifdef CONFIG_SMP
-extern void vm_acct_memory(long pages);
+DECLARE_PER_CPU(long, committed_space);
+
+/*
+ * We tolerate a little inaccuracy to avoid ping-ponging the counter between
+ * CPUs
+ */
+#define ACCT_THRESHOLD max(16, NR_CPUS * 2)
+
+static void inline vm_acct_memory(long pages)
+{
+ long *local;
+
+ preempt_disable();
+ local = &__get_cpu_var(committed_space);
+ *local += pages;
+ if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) {
+ atomic_add(*local, &vm_committed_space);
+ *local = 0;
+ }
+ preempt_enable();
+}
#else
static inline void vm_acct_memory(long pages)
{
diff -ruN -X dontdiff linux-2.5.69/mm/mmap.c linux-2.5.69-vm_acct_inline/mm/mmap.c
--- linux-2.5.69/mm/mmap.c Mon May 5 05:23:32 2003
+++ linux-2.5.69-vm_acct_inline/mm/mmap.c Tue May 20 12:05:36 2003
@@ -53,6 +53,10 @@
int sysctl_overcommit_ratio = 50; /* default is 50% */
atomic_t vm_committed_space = ATOMIC_INIT(0);

+#ifdef CONFIG_SMP
+DEFINE_PER_CPU(long, committed_space) = 0;
+#endif
+
/*
* Check that a process has enough memory to allocate a new virtual
* mapping. 1 means there is enough memory for the allocation to
diff -ruN -X dontdiff linux-2.5.69/mm/swap.c linux-2.5.69-vm_acct_inline/mm/swap.c
--- linux-2.5.69/mm/swap.c Mon May 5 05:23:13 2003
+++ linux-2.5.69-vm_acct_inline/mm/swap.c Tue May 20 11:50:59 2003
@@ -349,30 +349,6 @@
}


-#ifdef CONFIG_SMP
-/*
- * We tolerate a little inaccuracy to avoid ping-ponging the counter between
- * CPUs
- */
-#define ACCT_THRESHOLD max(16, NR_CPUS * 2)
-
-static DEFINE_PER_CPU(long, committed_space) = 0;
-
-void vm_acct_memory(long pages)
-{
- long *local;
-
- preempt_disable();
- local = &__get_cpu_var(committed_space);
- *local += pages;
- if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) {
- atomic_add(*local, &vm_committed_space);
- *local = 0;
- }
- preempt_enable();
-}
-#endif
-

/*
* Perform any setup for the swap system
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/