#include <linux/memory.h>
#include <linux/vmalloc.h>
#include <linux/cgroup.h>
+#include <linux/swapops.h>
static void __meminit
__init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
}
#endif
+
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+
+static DEFINE_MUTEX(swap_cgroup_mutex);
+struct swap_cgroup_ctrl {
+ struct page **map;
+ unsigned long length;
+};
+
+struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
+
+/*
+ * This 8bytes seems big..maybe we can reduce this when we can use "id" for
+ * cgroup rather than pointer.
+ */
+struct swap_cgroup {
+ struct mem_cgroup *val;
+};
+#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
+#define SC_POS_MASK (SC_PER_PAGE - 1)
+
+/*
+ * SwapCgroup implements "lookup" and "exchange" operations.
+ * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
+ * against SwapCache. At swap_free(), this is accessed directly from swap.
+ *
+ * This means,
+ * - we have no race in "exchange" when we're accessed via SwapCache because
+ * SwapCache(and its swp_entry) is under lock.
+ * - When called via swap_free(), there is no user of this entry and no race.
+ * Then, we don't need lock around "exchange".
+ *
+ * TODO: we can push these buffers out to HIGHMEM.
+ */
+
+/*
+ * allocate buffer for swap_cgroup.
+ */
+static int swap_cgroup_prepare(int type)
+{
+ struct page *page;
+ struct swap_cgroup_ctrl *ctrl;
+ unsigned long idx, max;
+
+ if (!do_swap_account)
+ return 0;
+ ctrl = &swap_cgroup_ctrl[type];
+
+ for (idx = 0; idx < ctrl->length; idx++) {
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ goto not_enough_page;
+ ctrl->map[idx] = page;
+ }
+ return 0;
+not_enough_page:
+ max = idx;
+ for (idx = 0; idx < max; idx++)
+ __free_page(ctrl->map[idx]);
+
+ return -ENOMEM;
+}
+
+/**
+ * swap_cgroup_record - record mem_cgroup for this swp_entry.
+ * @ent: swap entry to be recorded into
+ * @mem: mem_cgroup to be recorded
+ *
+ * Returns old value at success, NULL at failure.
+ * (Of course, old value can be NULL.)
+ */
+struct mem_cgroup *swap_cgroup_record(swp_entry_t ent, struct mem_cgroup *mem)
+{
+ int type = swp_type(ent);
+ unsigned long offset = swp_offset(ent);
+ unsigned long idx = offset / SC_PER_PAGE;
+ unsigned long pos = offset & SC_POS_MASK;
+ struct swap_cgroup_ctrl *ctrl;
+ struct page *mappage;
+ struct swap_cgroup *sc;
+ struct mem_cgroup *old;
+
+ if (!do_swap_account)
+ return NULL;
+
+ ctrl = &swap_cgroup_ctrl[type];
+
+ mappage = ctrl->map[idx];
+ sc = page_address(mappage);
+ sc += pos;
+ old = sc->val;
+ sc->val = mem;
+
+ return old;
+}
+
+/**
+ * lookup_swap_cgroup - lookup mem_cgroup tied to swap entry
+ * @ent: swap entry to be looked up.
+ *
+ * Returns pointer to mem_cgroup at success. NULL at failure.
+ */
+struct mem_cgroup *lookup_swap_cgroup(swp_entry_t ent)
+{
+ int type = swp_type(ent);
+ unsigned long offset = swp_offset(ent);
+ unsigned long idx = offset / SC_PER_PAGE;
+ unsigned long pos = offset & SC_POS_MASK;
+ struct swap_cgroup_ctrl *ctrl;
+ struct page *mappage;
+ struct swap_cgroup *sc;
+ struct mem_cgroup *ret;
+
+ if (!do_swap_account)
+ return NULL;
+
+ ctrl = &swap_cgroup_ctrl[type];
+ mappage = ctrl->map[idx];
+ sc = page_address(mappage);
+ sc += pos;
+ ret = sc->val;
+ return ret;
+}
+
+int swap_cgroup_swapon(int type, unsigned long max_pages)
+{
+ void *array;
+ unsigned long array_size;
+ unsigned long length;
+ struct swap_cgroup_ctrl *ctrl;
+
+ if (!do_swap_account)
+ return 0;
+
+ length = ((max_pages/SC_PER_PAGE) + 1);
+ array_size = length * sizeof(void *);
+
+ array = vmalloc(array_size);
+ if (!array)
+ goto nomem;
+
+ memset(array, 0, array_size);
+ ctrl = &swap_cgroup_ctrl[type];
+ mutex_lock(&swap_cgroup_mutex);
+ ctrl->length = length;
+ ctrl->map = array;
+ if (swap_cgroup_prepare(type)) {
+ /* memory shortage */
+ ctrl->map = NULL;
+ ctrl->length = 0;
+ vfree(array);
+ mutex_unlock(&swap_cgroup_mutex);
+ goto nomem;
+ }
+ mutex_unlock(&swap_cgroup_mutex);
+
+ printk(KERN_INFO
+ "swap_cgroup: uses %ld bytes of vmalloc for pointer array space"
+ " and %ld bytes to hold mem_cgroup pointers on swap\n",
+ array_size, length * PAGE_SIZE);
+ printk(KERN_INFO
+ "swap_cgroup can be disabled by noswapaccount boot option.\n");
+
+ return 0;
+nomem:
+ printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
+ printk(KERN_INFO
+ "swap_cgroup can be disabled by noswapaccount boot option\n");
+ return -ENOMEM;
+}
+
+void swap_cgroup_swapoff(int type)
+{
+ int i;
+ struct swap_cgroup_ctrl *ctrl;
+
+ if (!do_swap_account)
+ return;
+
+ mutex_lock(&swap_cgroup_mutex);
+ ctrl = &swap_cgroup_ctrl[type];
+ if (ctrl->map) {
+ for (i = 0; i < ctrl->length; i++) {
+ struct page *page = ctrl->map[i];
+ if (page)
+ __free_page(page);
+ }
+ vfree(ctrl->map);
+ ctrl->map = NULL;
+ ctrl->length = 0;
+ }
+ mutex_unlock(&swap_cgroup_mutex);
+}
+
+#endif
projects / openwrt / staging / blogic.git / commitdiff