Commit 4866920b authored Mar 22, 2006 by David Gibson Committed by Linus Torvalds Mar 22, 2006

[PATCH] hugepage: Fix hugepage logic in free_pgtables() harder



Turns out the hugepage logic in free_pgtables() was doubly broken.  The
loop coalescing multiple normal page VMAs into one call to free_pgd_range()
had an off by one error, which could mean it would coalesce one hugepage
VMA into the same bundle (checking 'vma' not 'next' in the loop).  I
transferred this bug into the new is_vm_hugetlb_page() based version.
Here's the fix.

This one didn't bite on powerpc previously for the same reason the
is_hugepage_only_range() problem didn't: powerpc's hugetlb_free_pgd_range()
is identical to free_pgd_range().  It didn't bite on ia64 because the
hugepage region is distant enough from any other region that the separated
PMD_SIZE distance test would always prevent coalescing the two together.

No libhugetlbfs testsuite regressions (ppc64, POWER5).

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 9da61aef

mm/memory.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -285,7 +285,7 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct vma,
		* Optimization: gather nearby vmas into one call down
		*/
		while (next && next->vm_start <= vma->vm_end + PMD_SIZE
		&& !is_vm_hugetlb_page(vma)) {
		&& !is_vm_hugetlb_page(next)) {
		vma = next;
		next = vma->vm_next;
		anon_vma_unlink(vma);

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