diff options
| author | de Dinechin, Christophe (Integrity VM) <christophe.de-dinechin@hp.com> | 2007-12-13 15:03:07 +0000 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2007-12-18 16:56:50 -0800 |
| commit | aec103bfa60e9f72bd66a144236592f54b986a03 (patch) | |
| tree | 90c1cf2de8853dd6e3972f295d1aecfe3aee507a | |
| parent | 3cdc7fc7fd5bd1ead75758dfadef609a6e9fd3de (diff) | |
| download | linux-aec103bfa60e9f72bd66a144236592f54b986a03.tar.bz2 | |
[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>
| -rw-r--r-- | arch/ia64/mm/tlb.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c index cef164729db7..655da240d13c 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 |