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Subject[PATCH 2/2 v5][rfc] tmpfs: interleave the starting node of /dev/shmem
Date
The tmpfs superblock grants an offset for each inode as they are created. Each
inode then uses that offset to provide a preferred first node for its interleave
in the newly provided shmem_interleave.

Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
---
include/linux/mm.h | 7 +++++++
include/linux/shmem_fs.h | 3 +++
mm/mempolicy.c | 4 ++++
mm/shmem.c | 17 +++++++++++++++++
4 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index b36d08c..651109e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -238,6 +238,13 @@ struct vm_operations_struct {
*/
struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
unsigned long addr);
+
+ /*
+ * If the policy is interleave allow the vma to suggest a node.
+ */
+ unsigned long (*interleave)(struct vm_area_struct *vma,
+ unsigned long addr);
+
int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
const nodemask_t *to, unsigned long flags);
#endif
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index bef2cf0..6995556 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -17,6 +17,7 @@ struct shmem_inode_info {
char *symlink; /* unswappable short symlink */
};
struct shared_policy policy; /* NUMA memory alloc policy */
+ unsigned long node_offset; /* bias for interleaved nodes */
struct list_head swaplist; /* chain of maybes on swap */
struct list_head xattr_list; /* list of shmem_xattr */
struct inode vfs_inode;
@@ -32,6 +33,8 @@ struct shmem_sb_info {
kgid_t gid; /* Mount gid for root directory */
umode_t mode; /* Mount mode for root directory */
struct mempolicy *mpol; /* default memory policy for mappings */
+ unsigned long next_pref_node;
+ /* next interleave bias to suggest for inodes */
};

static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1d771e4..e2cbe9e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1663,6 +1663,10 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
{
if (vma) {
unsigned long off;
+ if (vma->vm_ops && vma->vm_ops->interleave) {
+ off = vma->vm_ops->interleave(vma, addr);
+ return offset_il_node(pol, vma, off);
+ }

/*
* for small pages, there is no difference between
diff --git a/mm/shmem.c b/mm/shmem.c
index d073252..e569338 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -922,6 +922,7 @@ static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
pvma.vm_start = 0;
pvma.vm_pgoff = index;
pvma.vm_policy = spol;
+ pvma.vm_private_data = (void *) info->node_offset;
if (pvma.vm_policy)
pvma.vm_ops = &shmem_vm_ops;
else
@@ -938,6 +939,7 @@ static struct page *shmem_alloc_page(gfp_t gfp,
pvma.vm_start = 0;
pvma.vm_pgoff = index;
pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
+ pvma.vm_private_data = (void *) info->node_offset;
if (pvma.vm_policy)
pvma.vm_ops = &shmem_vm_ops;
else
@@ -1314,6 +1316,19 @@ static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
}
+
+static unsigned long shmem_interleave(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ unsigned long offset;
+
+ /* Use the vm_files prefered node as the initial offset. */
+ offset = (unsigned long *) vma->vm_private_data;
+
+ offset += ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+
+ return offset;
+}
#endif

int shmem_lock(struct file *file, int lock, struct user_struct *user)
@@ -1386,6 +1401,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
inode->i_fop = &shmem_file_operations;
mpol_shared_policy_init(&info->policy,
shmem_get_sbmpol(sbinfo));
+ info->node_offset = ++(sbinfo->next_pref_node);
break;
case S_IFDIR:
inc_nlink(inode);
@@ -2871,6 +2887,7 @@ static const struct super_operations shmem_ops = {
static const struct vm_operations_struct shmem_vm_ops = {
.fault = shmem_fault,
#ifdef CONFIG_NUMA
+ .interleave = shmem_interleave,
.set_policy = shmem_set_policy,
.get_policy = shmem_get_policy,
#endif
--
1.6.0.2


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