From: "'David Gibson'" <david@gibson.dropbear.id.au>
To: Andrew Morton <akpm@osdl.org>
Cc: Hugh Dickins <hugh@veritas.com>,
"Chen, Kenneth W" <kenneth.w.chen@intel.com>,
William Irwin <wli@holomorphy.com>,
linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: hugepage: Fix hugepage logic in free_pgtables() harder
Date: Fri, 3 Mar 2006 12:04:08 +1100 [thread overview]
Message-ID: <20060303010408.GG23766@localhost.localdomain> (raw)
Sigh. 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>
Index: working-2.6/mm/memory.c
===================================================================
--- working-2.6.orig/mm/memory.c 2006-03-03 11:39:33.000000000 +1100
+++ working-2.6/mm/memory.c 2006-03-03 11:39:50.000000000 +1100
@@ -285,7 +285,7 @@ void free_pgtables(struct mmu_gather **t
* 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);
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
next reply other threads:[~2006-03-03 1:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-03 1:04 'David Gibson' [this message]
2006-03-03 5:18 ` hugepage: Fix hugepage logic in free_pgtables() harder Hugh Dickins
2006-03-03 5:26 ` 'David Gibson'
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