Re: mmotm 2010-04-15-14-42 uploaded (shmem, CGROUP_MEM_RES_CTLR)

[Daisuke Nishimura]

On Fri, 16 Apr 2010 09:03:15 -0700, Randy Dunlap <randy.dunlap@xxxxxxxxxx> wrote:
> On Thu, 15 Apr 2010 14:42:59 -0700 akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> 
> > The mm-of-the-moment snapshot 2010-04-15-14-42 has been uploaded to
> > 
> >    http://userweb.kernel.org/~akpm/mmotm/
> > 
> > and will soon be available at
> > 
> >    git://zen-kernel.org/kernel/mmotm.git
> > 
> > It contains the following patches against 2.6.34-rc4:
> 
> 
> memcg-move-charge-of-file-pages.patch:
> 
> when CONFIG_SHMFS is not enabled:
> 
> mm/shmem.c:2721: error: implicit declaration of function 'SHMEM_I'
> mm/shmem.c:2721: warning: initialization makes pointer from integer without a cast
> mm/shmem.c:2726: error: dereferencing pointer to incomplete type
> mm/shmem.c:2727: error: implicit declaration of function 'shmem_swp_entry'
> mm/shmem.c:2727: warning: assignment makes pointer from integer without a cast
> mm/shmem.c:2734: error: implicit declaration of function 'shmem_swp_unmap'
> mm/shmem.c:2735: error: dereferencing pointer to incomplete type
> 
Thank you very much for your report.

I attach a fix patch.

===
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>

build fix for !CONFIG_SHMEM case.

  CC      mm/shmem.o
mm/shmem.c: In function 'mem_cgroup_get_shmem_target':
mm/shmem.c:2721: error: implicit declaration of function 'SHMEM_I'
mm/shmem.c:2721: warning: initialization makes pointer from integer without a cast
mm/shmem.c:2726: error: dereferencing pointer to incomplete type
mm/shmem.c:2727: error: implicit declaration of function 'shmem_swp_entry'
mm/shmem.c:2727: warning: assignment makes pointer from integer without a cast
mm/shmem.c:2734: error: implicit declaration of function 'shmem_swp_unmap'
mm/shmem.c:2735: error: dereferencing pointer to incomplete type
make[1]: *** [mm/shmem.o] Error 1

Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
---
 mm/shmem.c |   99 +++++++++++++++++++++++++++++++++++++----------------------
 1 files changed, 62 insertions(+), 37 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index cb87365..6f183ef 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2568,6 +2568,43 @@ out4:
 	return error;
 }
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+/**
+ * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
+ * @inode: the inode to be searched
+ * @pgoff: the offset to be searched
+ * @pagep: the pointer for the found page to be stored
+ * @ent: the pointer for the found swap entry to be stored
+ *
+ * If a page is found, refcount of it is incremented. Callers should handle
+ * these refcount.
+ */
+void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+					struct page **pagep, swp_entry_t *ent)
+{
+	swp_entry_t entry = { .val = 0 }, *ptr;
+	struct page *page = NULL;
+	struct shmem_inode_info *info = SHMEM_I(inode);
+
+	if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+		goto out;
+
+	spin_lock(&info->lock);
+	ptr = shmem_swp_entry(info, pgoff, NULL);
+	if (ptr && ptr->val) {
+		entry.val = ptr->val;
+		page = find_get_page(&swapper_space, entry.val);
+	} else
+		page = find_get_page(inode->i_mapping, pgoff);
+	if (ptr)
+		shmem_swp_unmap(ptr);
+	spin_unlock(&info->lock);
+out:
+	*pagep = page;
+	*ent = entry;
+}
+#endif
+
 #else /* !CONFIG_SHMEM */
 
 /*
@@ -2607,6 +2644,31 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
 	return 0;
 }
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+/**
+ * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
+ * @inode: the inode to be searched
+ * @pgoff: the offset to be searched
+ * @pagep: the pointer for the found page to be stored
+ * @ent: the pointer for the found swap entry to be stored
+ *
+ * If a page is found, refcount of it is incremented. Callers should handle
+ * these refcount.
+ */
+void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+					struct page **pagep, swp_entry_t *ent)
+{
+	struct page *page = NULL;
+
+	if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+		goto out;
+	page = find_get_page(inode->i_mapping, pgoff);
+out:
+	*pagep = page;
+	*ent = (swp_entry_t){ .val = 0 };
+}
+#endif
+
 #define shmem_vm_ops				generic_file_vm_ops
 #define shmem_file_operations			ramfs_file_operations
 #define shmem_get_inode(sb, mode, dev, flags)	ramfs_get_inode(sb, mode, dev)
@@ -2701,40 +2763,3 @@ int shmem_zero_setup(struct vm_area_struct *vma)
 	vma->vm_ops = &shmem_vm_ops;
 	return 0;
 }
-
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-/**
- * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
- * @inode: the inode to be searched
- * @pgoff: the offset to be searched
- * @pagep: the pointer for the found page to be stored
- * @ent: the pointer for the found swap entry to be stored
- *
- * If a page is found, refcount of it is incremented. Callers should handle
- * these refcount.
- */
-void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
-					struct page **pagep, swp_entry_t *ent)
-{
-	swp_entry_t entry = { .val = 0 }, *ptr;
-	struct page *page = NULL;
-	struct shmem_inode_info *info = SHMEM_I(inode);
-
-	if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
-		goto out;
-
-	spin_lock(&info->lock);
-	ptr = shmem_swp_entry(info, pgoff, NULL);
-	if (ptr && ptr->val) {
-		entry.val = ptr->val;
-		page = find_get_page(&swapper_space, entry.val);
-	} else
-		page = find_get_page(inode->i_mapping, pgoff);
-	if (ptr)
-		shmem_swp_unmap(ptr);
-	spin_unlock(&info->lock);
-out:
-	*pagep = page;
-	*ent = entry;
-}
-#endif
-- 
1.5.6.1

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