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From: Peter Zijlstra on 7 Jun 2010 07:30
From: Rik van Riel <riel(a)redhat.com>

Subsitute a direct call of spin_lock(anon_vma->lock) with
an inline function doing exactly the same.

This makes it easier to do the substitution to the root
anon_vma lock in a following patch.

We will deal with the handful of special locks (nested,
dec_and_lock, etc) separately.

Signed-off-by: Rik van Riel <riel(a)redhat.com>
Acked-by: Mel Gorman <mel(a)csn.ul.ie>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl>
LKML-Reference: <20100526153926.1272945b(a)annuminas.surriel.com>
---
include/linux/rmap.h | 10 ++++++++++
mm/ksm.c | 18 +++++++++---------
mm/migrate.c | 2 +-
mm/mmap.c | 2 +-
mm/rmap.c | 20 ++++++++++----------
5 files changed, 31 insertions(+), 21 deletions(-)

Index: linux-2.6/include/linux/rmap.h
===================================================================
--- linux-2.6.orig/include/linux/rmap.h
+++ linux-2.6/include/linux/rmap.h
@@ -113,6 +113,16 @@ static inline void vma_unlock_anon_vma(s
spin_unlock(&anon_vma->lock);
}

+static inline void anon_vma_lock(struct anon_vma *anon_vma)
+{
+ spin_lock(&anon_vma->lock);
+}
+
+static inline void anon_vma_unlock(struct anon_vma *anon_vma)
+{
+ spin_unlock(&anon_vma->lock);
+}
+
/*
* anon_vma helper functions.
*/
Index: linux-2.6/mm/ksm.c
===================================================================
--- linux-2.6.orig/mm/ksm.c
+++ linux-2.6/mm/ksm.c
@@ -327,7 +327,7 @@ static void drop_anon_vma(struct rmap_it

if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
int empty = list_empty(&anon_vma->head);
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
if (empty)
anon_vma_free(anon_vma);
}
@@ -1566,7 +1566,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1589,7 +1589,7 @@ again:
if (!search_new_forks || !mapcount)
break;
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
if (!mapcount)
goto out;
}
@@ -1619,7 +1619,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1637,11 +1637,11 @@ again:
ret = try_to_unmap_one(page, vma,
rmap_item->address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page)) {
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
goto out;
}
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}
if (!search_new_forks++)
goto again;
@@ -1671,7 +1671,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1688,11 +1688,11 @@ again:

ret = rmap_one(page, vma, rmap_item->address, arg);
if (ret != SWAP_AGAIN) {
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
goto out;
}
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}
if (!search_new_forks++)
goto again;
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c
+++ linux-2.6/mm/mmap.c
@@ -2589,7 +2589,7 @@ static void vm_unlock_anon_vma(struct an
if (!__test_and_clear_bit(0, (unsigned long *)
&anon_vma->head.next))
BUG();
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}
}

Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c
+++ linux-2.6/mm/rmap.c
@@ -134,7 +134,7 @@ int anon_vma_prepare(struct vm_area_stru
allocated = anon_vma;
}

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
/* page_table_lock to protect against threads */
spin_lock(&mm->page_table_lock);
if (likely(!vma->anon_vma)) {
@@ -147,7 +147,7 @@ int anon_vma_prepare(struct vm_area_stru
avc = NULL;
}
spin_unlock(&mm->page_table_lock);
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);

if (unlikely(allocated))
anon_vma_free(allocated);
@@ -170,9 +170,9 @@ static void anon_vma_chain_link(struct v
avc->anon_vma = anon_vma;
list_add(&avc->same_vma, &vma->anon_vma_chain);

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_add_tail(&avc->same_anon_vma, &anon_vma->head);
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}

/*
@@ -246,12 +246,12 @@ static void anon_vma_unlink(struct anon_
if (!anon_vma)
return;

- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_del(&anon_vma_chain->same_anon_vma);

/* We must garbage collect the anon_vma if it's empty */
empty = list_empty(&anon_vma->head) && !anonvma_external_refcount(anon_vma);
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);

if (empty)
anon_vma_free(anon_vma);
@@ -302,7 +302,7 @@ struct anon_vma *page_lock_anon_vma(stru
goto out;

anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
return anon_vma;
out:
rcu_read_unlock();
@@ -311,7 +311,7 @@ out:

void page_unlock_anon_vma(struct anon_vma *anon_vma)
{
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
rcu_read_unlock();
}

@@ -1389,7 +1389,7 @@ static int rmap_walk_anon(struct page *p
anon_vma = page_anon_vma(page);
if (!anon_vma)
return ret;
- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(avc, &anon_vma->head, same_anon_vma) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
@@ -1399,7 +1399,7 @@ static int rmap_walk_anon(struct page *p
if (ret != SWAP_AGAIN)
break;
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
return ret;
}

Index: linux-2.6/mm/migrate.c
===================================================================
--- linux-2.6.orig/mm/migrate.c
+++ linux-2.6/mm/migrate.c
@@ -684,7 +684,7 @@ rcu_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
int empty = list_empty(&anon_vma->head);
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
if (empty)
anon_vma_free(anon_vma);
}


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Prev: [PATCH 21/28] sparc64: Use RCU page table freeing.
Next: [PATCH 15/28] arm: Preemptible mmu_gather