From: Michel Lespinasse <walken@google.com>
To: linux-mm@kvack.org, riel@redhat.com, peterz@infradead.org,
aarcange@redhat.com, hughd@google.com, daniel.santos@pobox.com
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: [PATCH 5/7] mm rmap: remove vma_address check for address inside vma
Date: Tue, 4 Sep 2012 02:20:55 -0700 [thread overview]
Message-ID: <1346750457-12385-6-git-send-email-walken@google.com> (raw)
In-Reply-To: <1346750457-12385-1-git-send-email-walken@google.com>
In file and anon rmap, we use interval trees to find potentially relevant
vmas and then call vma_address() to find the virtual address the given
page might be found at in these vmas. vma_address() used to include a
check that the returned address falls within the limits of the vma, but
this check isn't necessary now that we always use interval trees in rmap:
the interval tree just doesn't return any vmas which this check would find
to be irrelevant. As a result, we can replace the use of -EFAULT error code
(which then needed to be checked in every call site) with a VM_BUG_ON().
Signed-off-by: Michel Lespinasse <walken@google.com>
---
mm/huge_memory.c | 4 ----
mm/rmap.c | 48 +++++++++++++++++++++---------------------------
2 files changed, 21 insertions(+), 31 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fe119cb71b41..91b65f962320 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1432,8 +1432,6 @@ static void __split_huge_page(struct page *page,
struct vm_area_struct *vma = avc->vma;
unsigned long addr = vma_address(page, vma);
BUG_ON(is_vma_temporary_stack(vma));
- if (addr == -EFAULT)
- continue;
mapcount += __split_huge_page_splitting(page, vma, addr);
}
/*
@@ -1458,8 +1456,6 @@ static void __split_huge_page(struct page *page,
struct vm_area_struct *vma = avc->vma;
unsigned long addr = vma_address(page, vma);
BUG_ON(is_vma_temporary_stack(vma));
- if (addr == -EFAULT)
- continue;
mapcount2 += __split_huge_page_map(page, vma, addr);
}
if (mapcount != mapcount2)
diff --git a/mm/rmap.c b/mm/rmap.c
index 9c61bf387fd1..28777412de62 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -510,22 +510,26 @@ void page_unlock_anon_vma(struct anon_vma *anon_vma)
/*
* At what user virtual address is page expected in @vma?
- * Returns virtual address or -EFAULT if page's index/offset is not
- * within the range mapped the @vma.
*/
-inline unsigned long
-vma_address(struct page *page, struct vm_area_struct *vma)
+static inline unsigned long
+__vma_address(struct page *page, struct vm_area_struct *vma)
{
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- unsigned long address;
if (unlikely(is_vm_hugetlb_page(vma)))
pgoff = page->index << huge_page_order(page_hstate(page));
- address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
- if (unlikely(address < vma->vm_start || address >= vma->vm_end)) {
- /* page should be within @vma mapping range */
- return -EFAULT;
- }
+
+ return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+}
+
+inline unsigned long
+vma_address(struct page *page, struct vm_area_struct *vma)
+{
+ unsigned long address = __vma_address(page, vma);
+
+ /* page should be within @vma mapping range */
+ VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+
return address;
}
@@ -535,6 +539,7 @@ vma_address(struct page *page, struct vm_area_struct *vma)
*/
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
+ unsigned long address;
if (PageAnon(page)) {
struct anon_vma *page__anon_vma = page_anon_vma(page);
/*
@@ -550,7 +555,10 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
return -EFAULT;
} else
return -EFAULT;
- return vma_address(page, vma);
+ address = __vma_address(page, vma);
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
+ return -EFAULT;
+ return address;
}
/*
@@ -624,8 +632,8 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
pte_t *pte;
spinlock_t *ptl;
- address = vma_address(page, vma);
- if (address == -EFAULT) /* out of vma range */
+ address = __vma_address(page, vma);
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
return 0;
pte = page_check_address(page, vma->vm_mm, address, &ptl, 1);
if (!pte) /* the page is not in this mm */
@@ -732,8 +740,6 @@ static int page_referenced_anon(struct page *page,
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
/*
* If we are reclaiming on behalf of a cgroup, skip
* counting on behalf of references from different
@@ -799,8 +805,6 @@ static int page_referenced_file(struct page *page,
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
/*
* If we are reclaiming on behalf of a cgroup, skip
* counting on behalf of references from different
@@ -904,8 +908,6 @@ static int page_mkclean_file(struct address_space *mapping, struct page *page)
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (vma->vm_flags & VM_SHARED) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret += page_mkclean_one(page, vma, address);
}
}
@@ -1468,8 +1470,6 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
continue;
address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = try_to_unmap_one(page, vma, address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page))
break;
@@ -1508,8 +1508,6 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
mutex_lock(&mapping->i_mmap_mutex);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = try_to_unmap_one(page, vma, address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page))
goto out;
@@ -1684,8 +1682,6 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = rmap_one(page, vma, address, arg);
if (ret != SWAP_AGAIN)
break;
@@ -1707,8 +1703,6 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
mutex_lock(&mapping->i_mmap_mutex);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);
- if (address == -EFAULT)
- continue;
ret = rmap_one(page, vma, address, arg);
if (ret != SWAP_AGAIN)
break;
--
1.7.7.3
next prev parent reply other threads:[~2012-09-04 9:21 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 9:20 [PATCH 0/7] use interval trees for anon rmap Michel Lespinasse
2012-09-04 9:20 ` [PATCH 1/7] mm: interval tree updates Michel Lespinasse
2012-09-07 22:13 ` Andrew Morton
2012-09-07 22:29 ` Michel Lespinasse
2012-09-07 22:55 ` Andrew Morton
2012-09-07 23:26 ` Michel Lespinasse
2012-09-08 4:45 ` Hillf Danton
2012-09-07 23:26 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 2/7] mm: fix potential anon_vma locking issue in mprotect() Michel Lespinasse
2012-09-04 14:27 ` Andrea Arcangeli
2012-09-04 21:53 ` Michel Lespinasse
2012-09-04 22:16 ` Andrea Arcangeli
2012-09-05 0:45 ` Michel Lespinasse
2012-09-04 9:20 ` [PATCH 3/7] mm anon rmap: remove anon_vma_moveto_tail Michel Lespinasse
2012-09-04 9:20 ` [PATCH 4/7] mm anon rmap: replace same_anon_vma linked list with an interval tree Michel Lespinasse
2012-09-05 0:51 ` Michel Lespinasse
2012-09-04 9:20 ` Michel Lespinasse [this message]
2012-09-04 9:20 ` [PATCH 6/7] mm: add CONFIG_DEBUG_VM_RB build option Michel Lespinasse
2012-09-14 22:14 ` Sasha Levin
2012-09-14 22:40 ` Sasha Levin
2012-09-14 22:46 ` Michel Lespinasse
2012-09-15 0:00 ` Michel Lespinasse
2012-09-15 7:52 ` Jiri Slaby
2012-09-16 19:07 ` Hugh Dickins
2012-09-22 7:19 ` Jiri Slaby
2012-09-15 9:26 ` Sasha Levin
2012-09-20 21:39 ` Fengguang Wu
2012-09-20 22:27 ` Hugh Dickins
2012-09-20 22:31 ` Fengguang Wu
2012-09-04 9:20 ` [PATCH 7/7] mm: avoid taking rmap locks in move_ptes() Michel Lespinasse
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