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authorde Dinechin, Christophe (Integrity VM) <christophe.de-dinechin@hp.com>2007-12-13 15:03:07 +0000
committerTony Luck <tony.luck@intel.com>2007-12-18 16:56:50 -0800
commitaec103bfa60e9f72bd66a144236592f54b986a03 (patch)
tree90c1cf2de8853dd6e3972f295d1aecfe3aee507a /arch/ia64/mm
parent3cdc7fc7fd5bd1ead75758dfadef609a6e9fd3de (diff)
[IA64] Avoid unnecessary TLB flushes when allocating memory
Improve performance of memory allocations on ia64 by avoiding a global TLB purge to purge a single page from the file cache. This happens whenever we evict a page from the buffer cache to make room for some other allocation. Test case: Run 'find /usr -type f | xargs cat > /dev/null' in the background to fill the buffer cache, then run something that uses memory, e.g. 'gmake -j50 install'. Instrumentation showed that the number of global TLB purges went from a few millions down to about 170 over a 12 hours run of the above. The performance impact is particularly noticeable under virtualization, because a virtual TLB is generally both larger and slower to purge than a physical one. Signed-off-by: Christophe de Dinechin <ddd@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/mm')
-rw-r--r--arch/ia64/mm/tlb.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index cef164729db..655da240d13 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -10,6 +10,7 @@
* IPI based ptc implementation and A-step IPI implementation.
* Rohit Seth <rohit.seth@intel.com>
* Ken Chen <kenneth.w.chen@intel.com>
+ * Christophe de Dinechin <ddd@hp.com>: Avoid ptc.e on memory allocation
*/
#include <linux/module.h>
#include <linux/init.h>
@@ -89,9 +90,16 @@ ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
{
static DEFINE_SPINLOCK(ptcg_lock);
- if (mm != current->active_mm || !current->mm) {
- flush_tlb_all();
- return;
+ struct mm_struct *active_mm = current->active_mm;
+
+ if (mm != active_mm) {
+ /* Restore region IDs for mm */
+ if (mm && active_mm) {
+ activate_context(mm);
+ } else {
+ flush_tlb_all();
+ return;
+ }
}
/* HW requires global serialization of ptc.ga. */
@@ -107,6 +115,10 @@ ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
} while (start < end);
}
spin_unlock(&ptcg_lock);
+
+ if (mm != active_mm) {
+ activate_context(active_mm);
+ }
}
void