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authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-25 16:00:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-25 16:00:17 -0700
commite4bc13adfd016fc1036838170288b5680d1a98b0 (patch)
tree8d2cb749397749439732f3a827cb7f2336408337 /mm/memcontrol.c
parentad90fb97515b732bc27a0109baa10af636c3c8cd (diff)
parent3e1534cf4a2a8278e811e7c84a79da1a02347b8b (diff)
Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block
Pull cgroup writeback support from Jens Axboe: "This is the big pull request for adding cgroup writeback support. This code has been in development for a long time, and it has been simmering in for-next for a good chunk of this cycle too. This is one of those problems that has been talked about for at least half a decade, finally there's a solution and code to go with it. Also see last weeks writeup on LWN: http://lwn.net/Articles/648292/" * 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits) writeback, blkio: add documentation for cgroup writeback support vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB writeback: do foreign inode detection iff cgroup writeback is enabled v9fs: fix error handling in v9fs_session_init() bdi: fix wrong error return value in cgwb_create() buffer: remove unusued 'ret' variable writeback: disassociate inodes from dying bdi_writebacks writeback: implement foreign cgroup inode bdi_writeback switching writeback: add lockdep annotation to inode_to_wb() writeback: use unlocked_inode_to_wb transaction in inode_congested() writeback: implement unlocked_inode_to_wb transaction and use it for stat updates writeback: implement [locked_]inode_to_wb_and_lock_list() writeback: implement foreign cgroup inode detection writeback: make writeback_control track the inode being written back writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb() mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use writeback: implement memcg writeback domain based throttling writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes writeback: implement memcg wb_domain writeback: update wb_over_bg_thresh() to use wb_domain aware operations ...
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c223
1 files changed, 172 insertions, 51 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e65f7b0131d3..acb93c554f6e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -77,6 +77,7 @@ EXPORT_SYMBOL(memory_cgrp_subsys);
#define MEM_CGROUP_RECLAIM_RETRIES 5
static struct mem_cgroup *root_mem_cgroup __read_mostly;
+struct cgroup_subsys_state *mem_cgroup_root_css __read_mostly;
/* Whether the swap controller is active */
#ifdef CONFIG_MEMCG_SWAP
@@ -90,6 +91,7 @@ static const char * const mem_cgroup_stat_names[] = {
"rss",
"rss_huge",
"mapped_file",
+ "dirty",
"writeback",
"swap",
};
@@ -322,11 +324,6 @@ struct mem_cgroup {
* percpu counter.
*/
struct mem_cgroup_stat_cpu __percpu *stat;
- /*
- * used when a cpu is offlined or other synchronizations
- * See mem_cgroup_read_stat().
- */
- struct mem_cgroup_stat_cpu nocpu_base;
spinlock_t pcp_counter_lock;
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
@@ -346,6 +343,11 @@ struct mem_cgroup {
atomic_t numainfo_updating;
#endif
+#ifdef CONFIG_CGROUP_WRITEBACK
+ struct list_head cgwb_list;
+ struct wb_domain cgwb_domain;
+#endif
+
/* List of events which userspace want to receive */
struct list_head event_list;
spinlock_t event_list_lock;
@@ -596,6 +598,39 @@ struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
return &memcg->css;
}
+/**
+ * mem_cgroup_css_from_page - css of the memcg associated with a page
+ * @page: page of interest
+ *
+ * If memcg is bound to the default hierarchy, css of the memcg associated
+ * with @page is returned. The returned css remains associated with @page
+ * until it is released.
+ *
+ * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
+ * is returned.
+ *
+ * XXX: The above description of behavior on the default hierarchy isn't
+ * strictly true yet as replace_page_cache_page() can modify the
+ * association before @page is released even on the default hierarchy;
+ * however, the current and planned usages don't mix the the two functions
+ * and replace_page_cache_page() will soon be updated to make the invariant
+ * actually true.
+ */
+struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
+{
+ struct mem_cgroup *memcg;
+
+ rcu_read_lock();
+
+ memcg = page->mem_cgroup;
+
+ if (!memcg || !cgroup_on_dfl(memcg->css.cgroup))
+ memcg = root_mem_cgroup;
+
+ rcu_read_unlock();
+ return &memcg->css;
+}
+
static struct mem_cgroup_per_zone *
mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
{
@@ -795,15 +830,8 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
long val = 0;
int cpu;
- get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
val += per_cpu(memcg->stat->count[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
- spin_lock(&memcg->pcp_counter_lock);
- val += memcg->nocpu_base.count[idx];
- spin_unlock(&memcg->pcp_counter_lock);
-#endif
- put_online_cpus();
return val;
}
@@ -813,15 +841,8 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
unsigned long val = 0;
int cpu;
- get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
val += per_cpu(memcg->stat->events[idx], cpu);
-#ifdef CONFIG_HOTPLUG_CPU
- spin_lock(&memcg->pcp_counter_lock);
- val += memcg->nocpu_base.events[idx];
- spin_unlock(&memcg->pcp_counter_lock);
-#endif
- put_online_cpus();
return val;
}
@@ -2020,6 +2041,7 @@ again:
return memcg;
}
+EXPORT_SYMBOL(mem_cgroup_begin_page_stat);
/**
* mem_cgroup_end_page_stat - finish a page state statistics transaction
@@ -2038,6 +2060,7 @@ void mem_cgroup_end_page_stat(struct mem_cgroup *memcg)
rcu_read_unlock();
}
+EXPORT_SYMBOL(mem_cgroup_end_page_stat);
/**
* mem_cgroup_update_page_stat - update page state statistics
@@ -2178,37 +2201,12 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
mutex_unlock(&percpu_charge_mutex);
}
-/*
- * This function drains percpu counter value from DEAD cpu and
- * move it to local cpu. Note that this function can be preempted.
- */
-static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
-{
- int i;
-
- spin_lock(&memcg->pcp_counter_lock);
- for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
- long x = per_cpu(memcg->stat->count[i], cpu);
-
- per_cpu(memcg->stat->count[i], cpu) = 0;
- memcg->nocpu_base.count[i] += x;
- }
- for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
- unsigned long x = per_cpu(memcg->stat->events[i], cpu);
-
- per_cpu(memcg->stat->events[i], cpu) = 0;
- memcg->nocpu_base.events[i] += x;
- }
- spin_unlock(&memcg->pcp_counter_lock);
-}
-
static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
unsigned long action,
void *hcpu)
{
int cpu = (unsigned long)hcpu;
struct memcg_stock_pcp *stock;
- struct mem_cgroup *iter;
if (action == CPU_ONLINE)
return NOTIFY_OK;
@@ -2216,9 +2214,6 @@ static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
return NOTIFY_OK;
- for_each_mem_cgroup(iter)
- mem_cgroup_drain_pcp_counter(iter, cpu);
-
stock = &per_cpu(memcg_stock, cpu);
drain_stock(stock);
return NOTIFY_OK;
@@ -4004,6 +3999,98 @@ static void memcg_destroy_kmem(struct mem_cgroup *memcg)
}
#endif
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg)
+{
+ return &memcg->cgwb_list;
+}
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return wb_domain_init(&memcg->cgwb_domain, gfp);
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+ wb_domain_exit(&memcg->cgwb_domain);
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+ wb_domain_size_changed(&memcg->cgwb_domain);
+}
+
+struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+
+ if (!memcg->css.parent)
+ return NULL;
+
+ return &memcg->cgwb_domain;
+}
+
+/**
+ * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
+ * @wb: bdi_writeback in question
+ * @pavail: out parameter for number of available pages
+ * @pdirty: out parameter for number of dirty pages
+ * @pwriteback: out parameter for number of pages under writeback
+ *
+ * Determine the numbers of available, dirty, and writeback pages in @wb's
+ * memcg. Dirty and writeback are self-explanatory. Available is a bit
+ * more involved.
+ *
+ * A memcg's headroom is "min(max, high) - used". The available memory is
+ * calculated as the lowest headroom of itself and the ancestors plus the
+ * number of pages already being used for file pages. Note that this
+ * doesn't consider the actual amount of available memory in the system.
+ * The caller should further cap *@pavail accordingly.
+ */
+void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pavail,
+ unsigned long *pdirty, unsigned long *pwriteback)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
+ struct mem_cgroup *parent;
+ unsigned long head_room = PAGE_COUNTER_MAX;
+ unsigned long file_pages;
+
+ *pdirty = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_DIRTY);
+
+ /* this should eventually include NR_UNSTABLE_NFS */
+ *pwriteback = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+
+ file_pages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
+ (1 << LRU_ACTIVE_FILE));
+ while ((parent = parent_mem_cgroup(memcg))) {
+ unsigned long ceiling = min(memcg->memory.limit, memcg->high);
+ unsigned long used = page_counter_read(&memcg->memory);
+
+ head_room = min(head_room, ceiling - min(ceiling, used));
+ memcg = parent;
+ }
+
+ *pavail = file_pages + head_room;
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
+{
+ return 0;
+}
+
+static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
+{
+}
+
+static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
+{
+}
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
+
/*
* DO NOT USE IN NEW FILES.
*
@@ -4388,9 +4475,15 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
if (!memcg->stat)
goto out_free;
+
+ if (memcg_wb_domain_init(memcg, GFP_KERNEL))
+ goto out_free_stat;
+
spin_lock_init(&memcg->pcp_counter_lock);
return memcg;
+out_free_stat:
+ free_percpu(memcg->stat);
out_free:
kfree(memcg);
return NULL;
@@ -4417,6 +4510,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
free_mem_cgroup_per_zone_info(memcg, node);
free_percpu(memcg->stat);
+ memcg_wb_domain_exit(memcg);
kfree(memcg);
}
@@ -4449,6 +4543,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
/* root ? */
if (parent_css == NULL) {
root_mem_cgroup = memcg;
+ mem_cgroup_root_css = &memcg->css;
page_counter_init(&memcg->memory, NULL);
memcg->high = PAGE_COUNTER_MAX;
memcg->soft_limit = PAGE_COUNTER_MAX;
@@ -4467,7 +4562,9 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
#ifdef CONFIG_MEMCG_KMEM
memcg->kmemcg_id = -1;
#endif
-
+#ifdef CONFIG_CGROUP_WRITEBACK
+ INIT_LIST_HEAD(&memcg->cgwb_list);
+#endif
return &memcg->css;
free_out:
@@ -4555,6 +4652,8 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
vmpressure_cleanup(&memcg->vmpressure);
memcg_deactivate_kmem(memcg);
+
+ wb_memcg_offline(memcg);
}
static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
@@ -4588,6 +4687,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
memcg->low = 0;
memcg->high = PAGE_COUNTER_MAX;
memcg->soft_limit = PAGE_COUNTER_MAX;
+ memcg_wb_domain_size_changed(memcg);
}
#ifdef CONFIG_MMU
@@ -4757,6 +4857,7 @@ static int mem_cgroup_move_account(struct page *page,
{
unsigned long flags;
int ret;
+ bool anon;
VM_BUG_ON(from == to);
VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -4782,15 +4883,33 @@ static int mem_cgroup_move_account(struct page *page,
if (page->mem_cgroup != from)
goto out_unlock;
+ anon = PageAnon(page);
+
spin_lock_irqsave(&from->move_lock, flags);
- if (!PageAnon(page) && page_mapped(page)) {
+ if (!anon && page_mapped(page)) {
__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
nr_pages);
__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
nr_pages);
}
+ /*
+ * move_lock grabbed above and caller set from->moving_account, so
+ * mem_cgroup_update_page_stat() will serialize updates to PageDirty.
+ * So mapping should be stable for dirty pages.
+ */
+ if (!anon && PageDirty(page)) {
+ struct address_space *mapping = page_mapping(page);
+
+ if (mapping_cap_account_dirty(mapping)) {
+ __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_DIRTY],
+ nr_pages);
+ __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_DIRTY],
+ nr_pages);
+ }
+ }
+
if (PageWriteback(page)) {
__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
nr_pages);
@@ -5306,6 +5425,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
memcg->high = high;
+ memcg_wb_domain_size_changed(memcg);
return nbytes;
}
@@ -5338,6 +5458,7 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
if (err)
return err;
+ memcg_wb_domain_size_changed(memcg);
return nbytes;
}