mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end
In order to allow sleeping during invalidate_page mmu notifier calls, we
need to avoid calling when holding the PT lock. In addition to its direct
calls, invalidate_page can also be called as a substitute for a change_pte
call, in case the notifier client hasn't implemented change_pte.
This patch drops the invalidate_page call from change_pte, and instead
wraps all calls to change_pte with invalidate_range_start and
invalidate_range_end calls.
Note that change_pte still cannot sleep after this patch, and that clients
implementing change_pte should not take action on it in case the number of
outstanding invalidate_range_start calls is larger than one, otherwise
they might miss a later invalidation.
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Cc: Liran Liss <liranl@mellanox.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/ksm.c b/mm/ksm.c
index ecbc090..ae539f0 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -709,15 +709,22 @@
spinlock_t *ptl;
int swapped;
int err = -EFAULT;
+ unsigned long mmun_start; /* For mmu_notifiers */
+ unsigned long mmun_end; /* For mmu_notifiers */
addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
goto out;
BUG_ON(PageTransCompound(page));
+
+ mmun_start = addr;
+ mmun_end = addr + PAGE_SIZE;
+ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+
ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
- goto out;
+ goto out_mn;
if (pte_write(*ptep) || pte_dirty(*ptep)) {
pte_t entry;
@@ -752,6 +759,8 @@
out_unlock:
pte_unmap_unlock(ptep, ptl);
+out_mn:
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
out:
return err;
}
@@ -776,6 +785,8 @@
spinlock_t *ptl;
unsigned long addr;
int err = -EFAULT;
+ unsigned long mmun_start; /* For mmu_notifiers */
+ unsigned long mmun_end; /* For mmu_notifiers */
addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
@@ -794,10 +805,14 @@
if (!pmd_present(*pmd))
goto out;
+ mmun_start = addr;
+ mmun_end = addr + PAGE_SIZE;
+ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+
ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte_same(*ptep, orig_pte)) {
pte_unmap_unlock(ptep, ptl);
- goto out;
+ goto out_mn;
}
get_page(kpage);
@@ -814,6 +829,8 @@
pte_unmap_unlock(ptep, ptl);
err = 0;
+out_mn:
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
out:
return err;
}