mm: memcontrol: rewrite charge API

[cascardo/linux.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index 57fd82a..1f1a808 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -293,7 +293,7 @@ static bool shmem_confirm_swap(struct address_space *mapping,
  */
 static int shmem_add_to_page_cache(struct page *page,
                                   struct address_space *mapping,
-                                  pgoff_t index, gfp_t gfp, void *expected)
+                                  pgoff_t index, void *expected)
 {
        int error;
 
@@ -621,7 +621,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
        radswap = swp_to_radix_entry(swap);
        index = radix_tree_locate_item(&mapping->page_tree, radswap);
        if (index == -1)
-               return 0;
+               return -EAGAIN; /* tell shmem_unuse we found nothing */
 
        /*
         * Move _head_ to start search for next from here.
@@ -666,7 +666,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
         */
        if (!error)
                error = shmem_add_to_page_cache(*pagep, mapping, index,
-                                               GFP_NOWAIT, radswap);
+                                               radswap);
        if (error != -ENOMEM) {
                /*
                 * Truncation and eviction use free_swap_and_cache(), which
@@ -680,7 +680,6 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
                        spin_unlock(&info->lock);
                        swap_free(swap);
                }
-               error = 1;      /* not an error, but entry was found */
        }
        return error;
 }
@@ -692,7 +691,7 @@ int shmem_unuse(swp_entry_t swap, struct page *page)
 {
        struct list_head *this, *next;
        struct shmem_inode_info *info;
-       int found = 0;
+       struct mem_cgroup *memcg;
        int error = 0;
 
        /*
@@ -707,26 +706,32 @@ int shmem_unuse(swp_entry_t swap, struct page *page)
         * the shmem_swaplist_mutex which might hold up shmem_writepage().
         * Charged back to the user (not to caller) when swap account is used.
         */
-       error = mem_cgroup_charge_file(page, current->mm, GFP_KERNEL);
+       error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg);
        if (error)
                goto out;
        /* No radix_tree_preload: swap entry keeps a place for page in tree */
+       error = -EAGAIN;
 
        mutex_lock(&shmem_swaplist_mutex);
        list_for_each_safe(this, next, &shmem_swaplist) {
                info = list_entry(this, struct shmem_inode_info, swaplist);
                if (info->swapped)
-                       found = shmem_unuse_inode(info, swap, &page);
+                       error = shmem_unuse_inode(info, swap, &page);
                else
                        list_del_init(&info->swaplist);
                cond_resched();
-               if (found)
+               if (error != -EAGAIN)
                        break;
+               /* found nothing in this: move on to search the next */
        }
        mutex_unlock(&shmem_swaplist_mutex);
 
-       if (found < 0)
-               error = found;
+       if (error) {
+               if (error != -ENOMEM)
+                       error = 0;
+               mem_cgroup_cancel_charge(page, memcg);
+       } else
+               mem_cgroup_commit_charge(page, memcg, true);
 out:
        unlock_page(page);
        page_cache_release(page);
@@ -1030,6 +1035,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
        struct address_space *mapping = inode->i_mapping;
        struct shmem_inode_info *info;
        struct shmem_sb_info *sbinfo;
+       struct mem_cgroup *memcg;
        struct page *page;
        swp_entry_t swap;
        int error;
@@ -1108,11 +1114,10 @@ repeat:
                                goto failed;
                }
 
-               error = mem_cgroup_charge_file(page, current->mm,
-                                               gfp & GFP_RECLAIM_MASK);
+               error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg);
                if (!error) {
                        error = shmem_add_to_page_cache(page, mapping, index,
-                                               gfp, swp_to_radix_entry(swap));
+                                               swp_to_radix_entry(swap));
                        /*
                         * We already confirmed swap under page lock, and make
                         * no memory allocation here, so usually no possibility
@@ -1125,12 +1130,16 @@ repeat:
                         * Reset swap.val? No, leave it so "failed" goes back to
                         * "repeat": reading a hole and writing should succeed.
                         */
-                       if (error)
+                       if (error) {
+                               mem_cgroup_cancel_charge(page, memcg);
                                delete_from_swap_cache(page);
+                       }
                }
                if (error)
                        goto failed;
 
+               mem_cgroup_commit_charge(page, memcg, true);
+
                spin_lock(&info->lock);
                info->swapped--;
                shmem_recalc_inode(inode);
@@ -1166,22 +1175,22 @@ repeat:
                __SetPageSwapBacked(page);
                __set_page_locked(page);
                if (sgp == SGP_WRITE)
-                       init_page_accessed(page);
+                       __SetPageReferenced(page);
 
-               error = mem_cgroup_charge_file(page, current->mm,
-                                               gfp & GFP_RECLAIM_MASK);
+               error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg);
                if (error)
                        goto decused;
                error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK);
                if (!error) {
                        error = shmem_add_to_page_cache(page, mapping, index,
-                                                       gfp, NULL);
+                                                       NULL);
                        radix_tree_preload_end();
                }
                if (error) {
-                       mem_cgroup_uncharge_cache_page(page);
+                       mem_cgroup_cancel_charge(page, memcg);
                        goto decused;
                }
+               mem_cgroup_commit_charge(page, memcg, false);
                lru_cache_add_anon(page);
 
                spin_lock(&info->lock);