@@ -54,13 +54,14 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
pte_t ptent;
bool updated = false;
- ptent = ptep_modify_prot_start(mm, addr, pte);
if (!prot_numa) {
+ ptent = ptep_modify_prot_start(mm, addr, pte);
ptent = pte_modify(ptent, newprot);
updated = true;
} else {
struct page *page;
+ ptent = *pte;
page = vm_normal_page(vma, addr, oldpte);
if (page) {
int this_nid = page_to_nid(page);
@@ -73,6 +74,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
if (!pte_numa(oldpte) &&
page_mapcount(page) == 1) {
ptent = pte_mknuma(ptent);
+ set_pte_at(mm, addr, pte, ptent);
updated = true;
}
}
@@ -89,7 +91,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
if (updated)
pages++;
- ptep_modify_prot_commit(mm, addr, pte, ptent);
+
+ /* Only !prot_numa always clears the pte */
+ if (!prot_numa)
+ ptep_modify_prot_commit(mm, addr, pte, ptent);
} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);
This is a note to let you know that I have just added a patch titled mm: numa: do not clear PTE for pte_numa update to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.16. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 32653cb12985177ab1745f255e43be66b1261d31 Mon Sep 17 00:00:00 2001 From: Mel Gorman <mgorman@suse.de> Date: Wed, 18 Dec 2013 17:08:37 -0800 Subject: mm: numa: do not clear PTE for pte_numa update commit 0c5f83c23ca703d32f930393825487257a5cde6d upstream. The TLB must be flushed if the PTE is updated but change_pte_range is clearing the PTE while marking PTEs pte_numa without necessarily flushing the TLB if it reinserts the same entry. Without the flush, it's conceivable that two processors have different TLBs for the same virtual address and at the very least it would generate spurious faults. This patch only unmaps the pages in change_pte_range for a full protection change. [riel@redhat.com: write pte_numa pte back to the page tables] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- mm/mprotect.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 1.8.3.2