relayfs: support larger relay buffer
[safe/jmp/linux-2.6] / mm / memcontrol.c
index 66d0e84..33add96 100644 (file)
 #include <linux/backing-dev.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 
 struct cgroup_subsys mem_cgroup_subsys;
 static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
+static struct kmem_cache *page_cgroup_cache;
 
 /*
  * Statistics for memory cgroup.
@@ -236,26 +239,12 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
                                css);
 }
 
-static struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
+struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 {
        return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
                                struct mem_cgroup, css);
 }
 
-void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
-{
-       struct mem_cgroup *mem;
-
-       mem = mem_cgroup_from_task(p);
-       css_get(&mem->css);
-       mm->mem_cgroup = mem;
-}
-
-void mm_free_cgroup(struct mm_struct *mm)
-{
-       css_put(&mm->mem_cgroup->css);
-}
-
 static inline int page_cgroup_locked(struct page *page)
 {
        return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
@@ -277,15 +266,20 @@ static void lock_page_cgroup(struct page *page)
        bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }
 
+static int try_lock_page_cgroup(struct page *page)
+{
+       return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+}
+
 static void unlock_page_cgroup(struct page *page)
 {
        bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }
 
-static void __mem_cgroup_remove_list(struct page_cgroup *pc)
+static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
+                       struct page_cgroup *pc)
 {
        int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
 
        if (from)
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
@@ -296,10 +290,10 @@ static void __mem_cgroup_remove_list(struct page_cgroup *pc)
        list_del_init(&pc->lru);
 }
 
-static void __mem_cgroup_add_list(struct page_cgroup *pc)
+static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
+                               struct page_cgroup *pc)
 {
        int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
 
        if (!to) {
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
@@ -351,14 +345,24 @@ void mem_cgroup_move_lists(struct page *page, bool active)
        struct mem_cgroup_per_zone *mz;
        unsigned long flags;
 
-       pc = page_get_page_cgroup(page);
-       if (!pc)
+       /*
+        * We cannot lock_page_cgroup while holding zone's lru_lock,
+        * because other holders of lock_page_cgroup can be interrupted
+        * with an attempt to rotate_reclaimable_page.  But we cannot
+        * safely get to page_cgroup without it, so just try_lock it:
+        * mem_cgroup_isolate_pages allows for page left on wrong list.
+        */
+       if (!try_lock_page_cgroup(page))
                return;
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_move_lists(pc, active);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       pc = page_get_page_cgroup(page);
+       if (pc) {
+               mz = page_cgroup_zoneinfo(pc);
+               spin_lock_irqsave(&mz->lru_lock, flags);
+               __mem_cgroup_move_lists(pc, active);
+               spin_unlock_irqrestore(&mz->lru_lock, flags);
+       }
+       unlock_page_cgroup(page);
 }
 
 /*
@@ -461,6 +465,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        int zid = zone_idx(z);
        struct mem_cgroup_per_zone *mz;
 
+       BUG_ON(!mem_cont);
        mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
        if (active)
                src = &mz->active_list;
@@ -518,6 +523,9 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
        unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
        struct mem_cgroup_per_zone *mz;
 
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
        /*
         * Should page_cgroup's go to their own slab?
         * One could optimize the performance of the charging routine
@@ -542,7 +550,7 @@ retry:
        }
        unlock_page_cgroup(page);
 
-       pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
+       pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
        if (pc == NULL)
                goto err;
 
@@ -556,7 +564,7 @@ retry:
                mm = &init_mm;
 
        rcu_read_lock();
-       mem = rcu_dereference(mm->mem_cgroup);
+       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
        /*
         * For every charge from the cgroup, increment reference count
         */
@@ -584,7 +592,6 @@ retry:
                        mem_cgroup_out_of_memory(mem, gfp_mask);
                        goto out;
                }
-               congestion_wait(WRITE, HZ/10);
        }
 
        pc->ref_cnt = 1;
@@ -592,7 +599,7 @@ retry:
        pc->page = page;
        pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
        if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
-               pc->flags |= PAGE_CGROUP_FLAG_CACHE;
+               pc->flags = PAGE_CGROUP_FLAG_CACHE;
 
        lock_page_cgroup(page);
        if (page_get_page_cgroup(page)) {
@@ -604,22 +611,22 @@ retry:
                 */
                res_counter_uncharge(&mem->res, PAGE_SIZE);
                css_put(&mem->css);
-               kfree(pc);
+               kmem_cache_free(page_cgroup_cache, pc);
                goto retry;
        }
        page_assign_page_cgroup(page, pc);
-       unlock_page_cgroup(page);
 
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(pc);
+       __mem_cgroup_add_list(mz, pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+       unlock_page_cgroup(page);
 done:
        return 0;
 out:
        css_put(&mem->css);
-       kfree(pc);
+       kmem_cache_free(page_cgroup_cache, pc);
 err:
        return -ENOMEM;
 }
@@ -650,6 +657,9 @@ void mem_cgroup_uncharge_page(struct page *page)
        struct mem_cgroup_per_zone *mz;
        unsigned long flags;
 
+       if (mem_cgroup_subsys.disabled)
+               return;
+
        /*
         * Check if our page_cgroup is valid
         */
@@ -662,19 +672,19 @@ void mem_cgroup_uncharge_page(struct page *page)
        VM_BUG_ON(pc->ref_cnt <= 0);
 
        if (--(pc->ref_cnt) == 0) {
-               page_assign_page_cgroup(page, NULL);
-               unlock_page_cgroup(page);
-
                mz = page_cgroup_zoneinfo(pc);
                spin_lock_irqsave(&mz->lru_lock, flags);
-               __mem_cgroup_remove_list(pc);
+               __mem_cgroup_remove_list(mz, pc);
                spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+               page_assign_page_cgroup(page, NULL);
+               unlock_page_cgroup(page);
+
                mem = pc->mem_cgroup;
                res_counter_uncharge(&mem->res, PAGE_SIZE);
                css_put(&mem->css);
 
-               kfree(pc);
+               kmem_cache_free(page_cgroup_cache, pc);
                return;
        }
 
@@ -690,6 +700,9 @@ int mem_cgroup_prepare_migration(struct page *page)
 {
        struct page_cgroup *pc;
 
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
        lock_page_cgroup(page);
        pc = page_get_page_cgroup(page);
        if (pc)
@@ -721,23 +734,24 @@ void mem_cgroup_page_migration(struct page *page, struct page *newpage)
                return;
        }
 
-       page_assign_page_cgroup(page, NULL);
-       unlock_page_cgroup(page);
-
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_remove_list(pc);
+       __mem_cgroup_remove_list(mz, pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+       page_assign_page_cgroup(page, NULL);
+       unlock_page_cgroup(page);
+
        pc->page = newpage;
        lock_page_cgroup(newpage);
        page_assign_page_cgroup(newpage, pc);
-       unlock_page_cgroup(newpage);
 
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(pc);
+       __mem_cgroup_add_list(mz, pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+       unlock_page_cgroup(newpage);
 }
 
 /*
@@ -752,7 +766,7 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
 {
        struct page_cgroup *pc;
        struct page *page;
-       int count;
+       int count = FORCE_UNCHARGE_BATCH;
        unsigned long flags;
        struct list_head *list;
 
@@ -761,35 +775,21 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
        else
                list = &mz->inactive_list;
 
-       if (list_empty(list))
-               return;
-retry:
-       count = FORCE_UNCHARGE_BATCH;
        spin_lock_irqsave(&mz->lru_lock, flags);
-
-       while (--count && !list_empty(list)) {
+       while (!list_empty(list)) {
                pc = list_entry(list->prev, struct page_cgroup, lru);
                page = pc->page;
-               lock_page_cgroup(page);
-               if (page_get_page_cgroup(page) == pc) {
-                       page_assign_page_cgroup(page, NULL);
-                       unlock_page_cgroup(page);
-                       __mem_cgroup_remove_list(pc);
-                       res_counter_uncharge(&mem->res, PAGE_SIZE);
-                       css_put(&mem->css);
-                       kfree(pc);
-               } else {
-                       /* racing uncharge: let page go then retry */
-                       unlock_page_cgroup(page);
-                       break;
+               get_page(page);
+               spin_unlock_irqrestore(&mz->lru_lock, flags);
+               mem_cgroup_uncharge_page(page);
+               put_page(page);
+               if (--count <= 0) {
+                       count = FORCE_UNCHARGE_BATCH;
+                       cond_resched();
                }
+               spin_lock_irqsave(&mz->lru_lock, flags);
        }
-
        spin_unlock_irqrestore(&mz->lru_lock, flags);
-       if (!list_empty(list)) {
-               cond_resched();
-               goto retry;
-       }
 }
 
 /*
@@ -801,6 +801,9 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem)
        int ret = -EBUSY;
        int node, zid;
 
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
        css_get(&mem->css);
        /*
         * page reclaim code (kswapd etc..) will move pages between
@@ -839,13 +842,10 @@ static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
        return 0;
 }
 
-static ssize_t mem_cgroup_read(struct cgroup *cont,
-                       struct cftype *cft, struct file *file,
-                       char __user *userbuf, size_t nbytes, loff_t *ppos)
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
-       return res_counter_read(&mem_cgroup_from_cont(cont)->res,
-                               cft->private, userbuf, nbytes, ppos,
-                               NULL);
+       return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
+                                   cft->private);
 }
 
 static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
@@ -857,27 +857,25 @@ static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                                mem_cgroup_write_strategy);
 }
 
-static ssize_t mem_force_empty_write(struct cgroup *cont,
-                               struct cftype *cft, struct file *file,
-                               const char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
-       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-       int ret = mem_cgroup_force_empty(mem);
-       if (!ret)
-               ret = nbytes;
-       return ret;
+       struct mem_cgroup *mem;
+
+       mem = mem_cgroup_from_cont(cont);
+       switch (event) {
+       case RES_MAX_USAGE:
+               res_counter_reset_max(&mem->res);
+               break;
+       case RES_FAILCNT:
+               res_counter_reset_failcnt(&mem->res);
+               break;
+       }
+       return 0;
 }
 
-/*
- * Note: This should be removed if cgroup supports write-only file.
- */
-static ssize_t mem_force_empty_read(struct cgroup *cont,
-                               struct cftype *cft,
-                               struct file *file, char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
 {
-       return -EINVAL;
+       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
 }
 
 static const struct mem_cgroup_stat_desc {
@@ -888,9 +886,9 @@ static const struct mem_cgroup_stat_desc {
        [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
 };
 
-static int mem_control_stat_show(struct seq_file *m, void *arg)
+static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
+                                struct cgroup_map_cb *cb)
 {
-       struct cgroup *cont = m->private;
        struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
        struct mem_cgroup_stat *stat = &mem_cont->stat;
        int i;
@@ -900,8 +898,7 @@ static int mem_control_stat_show(struct seq_file *m, void *arg)
 
                val = mem_cgroup_read_stat(stat, i);
                val *= mem_cgroup_stat_desc[i].unit;
-               seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg,
-                               (long long)val);
+               cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
        }
        /* showing # of active pages */
        {
@@ -911,52 +908,43 @@ static int mem_control_stat_show(struct seq_file *m, void *arg)
                                                MEM_CGROUP_ZSTAT_INACTIVE);
                active = mem_cgroup_get_all_zonestat(mem_cont,
                                                MEM_CGROUP_ZSTAT_ACTIVE);
-               seq_printf(m, "active %ld\n", (active) * PAGE_SIZE);
-               seq_printf(m, "inactive %ld\n", (inactive) * PAGE_SIZE);
+               cb->fill(cb, "active", (active) * PAGE_SIZE);
+               cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
        }
        return 0;
 }
 
-static const struct file_operations mem_control_stat_file_operations = {
-       .read = seq_read,
-       .llseek = seq_lseek,
-       .release = single_release,
-};
-
-static int mem_control_stat_open(struct inode *unused, struct file *file)
-{
-       /* XXX __d_cont */
-       struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
-
-       file->f_op = &mem_control_stat_file_operations;
-       return single_open(file, mem_control_stat_show, cont);
-}
-
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
                .private = RES_USAGE,
-               .read = mem_cgroup_read,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "max_usage_in_bytes",
+               .private = RES_MAX_USAGE,
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "limit_in_bytes",
                .private = RES_LIMIT,
                .write = mem_cgroup_write,
-               .read = mem_cgroup_read,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "failcnt",
                .private = RES_FAILCNT,
-               .read = mem_cgroup_read,
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "force_empty",
-               .write = mem_force_empty_write,
-               .read = mem_force_empty_read,
+               .trigger = mem_force_empty_write,
        },
        {
                .name = "stat",
-               .open = mem_control_stat_open,
+               .read_map = mem_control_stat_show,
        },
 };
 
@@ -964,7 +952,7 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
        struct mem_cgroup_per_node *pn;
        struct mem_cgroup_per_zone *mz;
-       int zone;
+       int zone, tmp = node;
        /*
         * This routine is called against possible nodes.
         * But it's BUG to call kmalloc() against offline node.
@@ -973,10 +961,9 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
         *       never be onlined. It's better to use memory hotplug callback
         *       function.
         */
-       if (node_state(node, N_HIGH_MEMORY))
-               pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
-       else
-               pn = kmalloc(sizeof(*pn), GFP_KERNEL);
+       if (!node_state(node, N_NORMAL_MEMORY))
+               tmp = -1;
+       pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
        if (!pn)
                return 1;
 
@@ -997,6 +984,29 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
        kfree(mem->info.nodeinfo[node]);
 }
 
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+       struct mem_cgroup *mem;
+
+       if (sizeof(*mem) < PAGE_SIZE)
+               mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+       else
+               mem = vmalloc(sizeof(*mem));
+
+       if (mem)
+               memset(mem, 0, sizeof(*mem));
+       return mem;
+}
+
+static void mem_cgroup_free(struct mem_cgroup *mem)
+{
+       if (sizeof(*mem) < PAGE_SIZE)
+               kfree(mem);
+       else
+               vfree(mem);
+}
+
+
 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
@@ -1005,17 +1015,15 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 
        if (unlikely((cont->parent) == NULL)) {
                mem = &init_mem_cgroup;
-               init_mm.mem_cgroup = mem;
-       } else
-               mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
-
-       if (mem == NULL)
-               return ERR_PTR(-ENOMEM);
+               page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
+       } else {
+               mem = mem_cgroup_alloc();
+               if (!mem)
+                       return ERR_PTR(-ENOMEM);
+       }
 
        res_counter_init(&mem->res);
 
-       memset(&mem->info, 0, sizeof(mem->info));
-
        for_each_node_state(node, N_POSSIBLE)
                if (alloc_mem_cgroup_per_zone_info(mem, node))
                        goto free_out;
@@ -1025,7 +1033,7 @@ free_out:
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
        if (cont->parent != NULL)
-               kfree(mem);
+               mem_cgroup_free(mem);
        return ERR_PTR(-ENOMEM);
 }
 
@@ -1045,12 +1053,14 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
 
-       kfree(mem_cgroup_from_cont(cont));
+       mem_cgroup_free(mem_cgroup_from_cont(cont));
 }
 
 static int mem_cgroup_populate(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
+       if (mem_cgroup_subsys.disabled)
+               return 0;
        return cgroup_add_files(cont, ss, mem_cgroup_files,
                                        ARRAY_SIZE(mem_cgroup_files));
 }
@@ -1063,6 +1073,9 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
        struct mm_struct *mm;
        struct mem_cgroup *mem, *old_mem;
 
+       if (mem_cgroup_subsys.disabled)
+               return;
+
        mm = get_task_mm(p);
        if (mm == NULL)
                return;
@@ -1077,13 +1090,9 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
         * Only thread group leaders are allowed to migrate, the mm_struct is
         * in effect owned by the leader
         */
-       if (p->tgid != p->pid)
+       if (!thread_group_leader(p))
                goto out;
 
-       css_get(&mem->css);
-       rcu_assign_pointer(mm->mem_cgroup, mem);
-       css_put(&old_mem->css);
-
 out:
        mmput(mm);
 }