From 71b54f8263860a37dd9f50f81880a9d681fd9c10 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 21 Jan 2014 14:33:19 -0800 Subject: [PATCH] x86/mm: Eliminate redundant page table walk during TLB range flushing When choosing between doing an address space or ranged flush, the x86 implementation of flush_tlb_mm_range takes into account whether there are any large pages in the range. A per-page flush typically requires fewer entries than would covered by a single large page and the check is redundant. There is one potential exception. THP migration flushes single THP entries and it conceivably would benefit from flushing a single entry instead of the mm. However, this flush is after a THP allocation, copy and page table update potentially with any other threads serialised behind it. In comparison to that, the flush is noise. It makes more sense to optimise balancing to require fewer flushes than to optimise the flush itself. This patch deletes the redundant huge page check. Signed-off-by: Mel Gorman Tested-by: Davidlohr Bueso Reviewed-by: Rik van Riel Signed-off-by: Andrew Morton Cc: Alex Shi Cc: Linus Torvalds Cc: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-sgei1drpOcburujPsfh6ovmo@git.kernel.org Signed-off-by: Ingo Molnar --- Reading git-format-patch failed