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Subject[PATCH 03/18] mm, hugetlb: unify region structure handling
Date
Currently, to track a reserved and allocated region, we use two different
ways for MAP_SHARED and MAP_PRIVATE. For MAP_SHARED, we use
address_mapping's private_list and, for MAP_PRIVATE, we use a resv_map.
Now, we are preparing to change a coarse grained lock which protect
a region structure to fine grained lock, and this difference hinder it.
So, before changing it, unify region structure handling.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index a3f868a..a1ae3ada 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -366,7 +366,12 @@ static void truncate_hugepages(struct inode *inode, loff_t lstart)

static void hugetlbfs_evict_inode(struct inode *inode)
{
+ struct resv_map *resv_map;
+
truncate_hugepages(inode, 0);
+ resv_map = (struct resv_map *)inode->i_mapping->private_data;
+ if (resv_map)
+ kref_put(&resv_map->refs, resv_map_release);
clear_inode(inode);
}

@@ -468,6 +473,11 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
umode_t mode, dev_t dev)
{
struct inode *inode;
+ struct resv_map *resv_map;
+
+ resv_map = resv_map_alloc();
+ if (!resv_map)
+ return NULL;

inode = new_inode(sb);
if (inode) {
@@ -477,7 +487,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
inode->i_mapping->a_ops = &hugetlbfs_aops;
inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- INIT_LIST_HEAD(&inode->i_mapping->private_list);
+ inode->i_mapping->private_data = resv_map;
info = HUGETLBFS_I(inode);
/*
* The policy is initialized here even if we are creating a
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 6b4890f..2677c07 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -5,6 +5,8 @@
#include <linux/fs.h>
#include <linux/hugetlb_inline.h>
#include <linux/cgroup.h>
+#include <linux/list.h>
+#include <linux/kref.h>

struct ctl_table;
struct user_struct;
@@ -22,6 +24,13 @@ struct hugepage_subpool {
long max_hpages, used_hpages;
};

+struct resv_map {
+ struct kref refs;
+ struct list_head regions;
+};
+extern struct resv_map *resv_map_alloc(void);
+void resv_map_release(struct kref *ref);
+
extern spinlock_t hugetlb_lock;
extern int hugetlb_max_hstate __read_mostly;
#define for_each_hstate(h) \
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 12b6581..35f6b12 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -375,12 +375,7 @@ static void set_vma_private_data(struct vm_area_struct *vma,
vma->vm_private_data = (void *)value;
}

-struct resv_map {
- struct kref refs;
- struct list_head regions;
-};
-
-static struct resv_map *resv_map_alloc(void)
+struct resv_map *resv_map_alloc(void)
{
struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
if (!resv_map)
@@ -392,7 +387,7 @@ static struct resv_map *resv_map_alloc(void)
return resv_map;
}

-static void resv_map_release(struct kref *ref)
+void resv_map_release(struct kref *ref)
{
struct resv_map *resv_map = container_of(ref, struct resv_map, refs);

@@ -1086,8 +1081,9 @@ static long vma_needs_reservation(struct hstate *h,

if (vma->vm_flags & VM_MAYSHARE) {
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
- return region_chg(&inode->i_mapping->private_list,
- idx, idx + 1);
+ struct resv_map *resv = inode->i_mapping->private_data;
+
+ return region_chg(&resv->regions, idx, idx + 1);

} else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
return 1;
@@ -1111,7 +1107,9 @@ static void vma_commit_reservation(struct hstate *h,

if (vma->vm_flags & VM_MAYSHARE) {
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
- region_add(&inode->i_mapping->private_list, idx, idx + 1);
+ struct resv_map *resv = inode->i_mapping->private_data;
+
+ region_add(&resv->regions, idx, idx + 1);

} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
@@ -3061,6 +3059,7 @@ int hugetlb_reserve_pages(struct inode *inode,
long ret, chg;
struct hstate *h = hstate_inode(inode);
struct hugepage_subpool *spool = subpool_inode(inode);
+ struct resv_map *resv_map;

/*
* Only apply hugepage reservation if asked. At fault time, an
@@ -3076,10 +3075,13 @@ int hugetlb_reserve_pages(struct inode *inode,
* to reserve the full area even if read-only as mprotect() may be
* called to make the mapping read-write. Assume !vma is a shm mapping
*/
- if (!vma || vma->vm_flags & VM_MAYSHARE)
- chg = region_chg(&inode->i_mapping->private_list, from, to);
- else {
- struct resv_map *resv_map = resv_map_alloc();
+ if (!vma || vma->vm_flags & VM_MAYSHARE) {
+ resv_map = inode->i_mapping->private_data;
+
+ chg = region_chg(&resv_map->regions, from, to);
+
+ } else {
+ resv_map = resv_map_alloc();
if (!resv_map)
return -ENOMEM;

@@ -3122,7 +3124,7 @@ int hugetlb_reserve_pages(struct inode *inode,
* else has to be done for private mappings here
*/
if (!vma || vma->vm_flags & VM_MAYSHARE)
- region_add(&inode->i_mapping->private_list, from, to);
+ region_add(&resv_map->regions, from, to);
return 0;
out_err:
if (vma)
@@ -3133,9 +3135,12 @@ out_err:
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
{
struct hstate *h = hstate_inode(inode);
- long chg = region_truncate(&inode->i_mapping->private_list, offset);
+ struct resv_map *resv_map = inode->i_mapping->private_data;
+ long chg = 0;
struct hugepage_subpool *spool = subpool_inode(inode);

+ if (resv_map)
+ chg = region_truncate(&resv_map->regions, offset);
spin_lock(&inode->i_lock);
inode->i_blocks -= (blocks_per_huge_page(h) * freed);
spin_unlock(&inode->i_lock);
--
1.7.9.5


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