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@xxxxxx> --- diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c index 1682fc6..66ae9c4 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@xxxxxxxxx> * Ken Chen <kenneth.w.chen@xxxxxxxxx> + * Christophe de Dinechin <ddd@xxxxxx>: 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 - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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