Message-Id: <1498141404-18807-4-git-send-email-nborisov@suse.com>
Date:   Thu, 22 Jun 2017 17:23:23 +0300
From:   Nikolay Borisov <nborisov@...e.com>
To:     tj@...nel.org
Cc:     jbacik@...com, jack@...e.cz, jeffm@...e.com,
        chandan@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-btrfs@...r.kernel.org, axboe@...nel.dk,
        Nikolay Borisov <nborisov@...e.com>
Subject: [PATCH 3/4] writeback: add counters for metadata usage

From: Josef Bacik <jbacik@...com>

Btrfs has no bounds except memory on the amount of dirty memory that we have in
use for metadata.  Historically we have used a special inode so we could take
advantage of the balance_dirty_pages throttling that comes with using pagecache.
However as we'd like to support different blocksizes it would be nice to not
have to rely on pagecache, but still get the balance_dirty_pages throttling
without having to do it ourselves.

So introduce *METADATA_DIRTY_BYTES and *METADATA_WRITEBACK_BYTES.  These are
zone and bdi_writeback counters to keep track of how many bytes we have in
flight for METADATA.  We need to count in bytes as blocksizes could be
percentages of pagesize.  We simply convert the bytes to number of pages where
it is needed for the throttling.

Also introduce NR_METADATA_BYTES so we can keep track of the total amount of
pages used for metadata on the system.  This is also needed so things like dirty
throttling know that this is dirtyable memory as well and easily reclaimed.

This patch doesn't introduce any functional changes.

Signed-off-by: Josef Bacik <jbacik@...com>
Signed-off-by: Nikolay Borisov <nborisov@...e.com>
---

Changs since previous posting [1]: 
 
 - Forward ported to 4.12-rc6

 - Factored out the __add_wb_stats calls outside of irq-disable region 
 since it's already irq-safe. This was commented on by Tejun in the previous
 posting. 

 This patch had a Reviewed-by: Jan Kara <jack@...e.cz> tag but I've omitted
 it due to my changes. 

[1] https://patchwork.kernel.org/patch/9395205/

 drivers/base/node.c              |   8 ++
 fs/fs-writeback.c                |   2 +
 fs/proc/meminfo.c                |   6 ++
 include/linux/backing-dev-defs.h |   2 +
 include/linux/backing-dev.h      |   2 +
 include/linux/mm.h               |   9 +++
 include/linux/mmzone.h           |   3 +
 include/trace/events/writeback.h |  13 +++-
 mm/backing-dev.c                 |   4 +
 mm/page-writeback.c              | 157 +++++++++++++++++++++++++++++++++++----
 mm/page_alloc.c                  |  21 +++++-
 mm/util.c                        |   2 +
 mm/vmscan.c                      |  19 ++++-
 mm/vmstat.c                      |   3 +
 14 files changed, 229 insertions(+), 22 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index b6f563a3a3a9..65deb8ece4b9 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -50,6 +50,8 @@ static inline ssize_t node_read_cpulist(struct device *dev,
 static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
 static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
 
+#define BtoK(x) ((x) >> 10)
+
 static ssize_t node_read_meminfo(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
@@ -98,7 +100,10 @@ static ssize_t node_read_meminfo(struct device *dev,
 #endif
 	n += sprintf(buf + n,
 		       "Node %d Dirty:          %8lu kB\n"
+		       "Node %d MetadataDirty:	%8lu kB\n"
 		       "Node %d Writeback:      %8lu kB\n"
+		       "Node %d MetaWriteback:  %8lu kB\n"
+		       "Node %d Metadata:       %8lu kB\n"
 		       "Node %d FilePages:      %8lu kB\n"
 		       "Node %d Mapped:         %8lu kB\n"
 		       "Node %d AnonPages:      %8lu kB\n"
@@ -118,7 +123,10 @@ static ssize_t node_read_meminfo(struct device *dev,
 #endif
 			,
 		       nid, PtoK(node_page_state(pgdat, NR_FILE_DIRTY)),
+		       nid, BtoK(node_page_state(pgdat, NR_METADATA_DIRTY_BYTES)),
 		       nid, PtoK(node_page_state(pgdat, NR_WRITEBACK)),
+		       nid, BtoK(node_page_state(pgdat, NR_METADATA_WRITEBACK_BYTES)),
+		       nid, BtoK(node_page_state(pgdat, NR_METADATA_BYTES)),
 		       nid, PtoK(node_page_state(pgdat, NR_FILE_PAGES)),
 		       nid, PtoK(node_page_state(pgdat, NR_FILE_MAPPED)),
 		       nid, PtoK(node_page_state(pgdat, NR_ANON_MAPPED)),
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 309364aab2a5..c7b33d124f3d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1814,6 +1814,7 @@ static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb)
 	return work;
 }
 
+#define BtoP(x) ((x) >> PAGE_SHIFT)
 /*
  * Add in the number of potentially dirty inodes, because each inode
  * write can dirty pagecache in the underlying blockdev.
@@ -1822,6 +1823,7 @@ static unsigned long get_nr_dirty_pages(void)
 {
 	return global_node_page_state(NR_FILE_DIRTY) +
 		global_node_page_state(NR_UNSTABLE_NFS) +
+		BtoP(global_node_page_state(NR_METADATA_DIRTY_BYTES)) +
 		get_nr_dirty_inodes();
 }
 
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 8a428498d6b2..33eb566e04c5 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -71,6 +71,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "Buffers:        ", i.bufferram);
 	show_val_kb(m, "Cached:         ", cached);
 	show_val_kb(m, "SwapCached:     ", total_swapcache_pages());
+	show_val_kb(m, "Metadata:	",
+		    global_node_page_state(NR_METADATA_BYTES) >> PAGE_SHIFT);
 	show_val_kb(m, "Active:         ", pages[LRU_ACTIVE_ANON] +
 					   pages[LRU_ACTIVE_FILE]);
 	show_val_kb(m, "Inactive:       ", pages[LRU_INACTIVE_ANON] +
@@ -98,8 +100,12 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "SwapFree:       ", i.freeswap);
 	show_val_kb(m, "Dirty:          ",
 		    global_node_page_state(NR_FILE_DIRTY));
+	show_val_kb(m, "MetaDirty:	",
+		    global_node_page_state(NR_METADATA_DIRTY_BYTES) >> PAGE_SHIFT);
 	show_val_kb(m, "Writeback:      ",
 		    global_node_page_state(NR_WRITEBACK));
+	show_val_kb(m, "MetaWriteback:	",
+		    global_node_page_state(NR_METADATA_WRITEBACK_BYTES) >> PAGE_SHIFT);
 	show_val_kb(m, "AnonPages:      ",
 		    global_node_page_state(NR_ANON_MAPPED));
 	show_val_kb(m, "Mapped:         ",
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index ded45ac2cec7..78c65e2910dc 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -38,6 +38,8 @@ enum wb_stat_item {
 	WB_WRITEBACK,
 	WB_DIRTIED_BYTES,
 	WB_WRITTEN_BYTES,
+	WB_METADATA_DIRTY_BYTES,
+	WB_METADATA_WRITEBACK_BYTES,
 	NR_WB_STAT_ITEMS
 };
 
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 8b5a2e98b779..a73178b471e6 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -75,6 +75,8 @@ static inline void __add_wb_stat(struct bdi_writeback *wb,
 	switch (item) {
 	case WB_DIRTIED_BYTES:
 	case WB_WRITTEN_BYTES:
+	case WB_METADATA_DIRTY_BYTES:
+	case WB_METADATA_WRITEBACK_BYTES:
 		batch_size = WB_STAT_BATCH << PAGE_SHIFT;
 		break;
 	default:
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d8d80e2e9194..f506111896a3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -31,6 +31,7 @@ struct file_ra_state;
 struct user_struct;
 struct writeback_control;
 struct bdi_writeback;
+struct backing_dev_info;
 
 void init_mm_internals(void);
 
@@ -1388,6 +1389,14 @@ int redirty_page_for_writepage(struct writeback_control *wbc,
 void account_page_dirtied(struct page *page, struct address_space *mapping);
 void account_page_cleaned(struct page *page, struct address_space *mapping,
 			  struct bdi_writeback *wb);
+void account_metadata_dirtied(struct page *page, struct backing_dev_info *bdi,
+			      long bytes);
+void account_metadata_cleaned(struct page *page, struct backing_dev_info *bdi,
+			      long bytes);
+void account_metadata_writeback(struct page *page,
+				struct backing_dev_info *bdi, long bytes);
+void account_metadata_end_writeback(struct page *page,
+				    struct backing_dev_info *bdi, long bytes);
 int set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);
 void cancel_dirty_page(struct page *page);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index ef6a13b7bd3e..9ab6e3b255e7 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -173,6 +173,9 @@ enum node_stat_item {
 	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
 	NR_DIRTIED,		/* page dirtyings since bootup */
 	NR_WRITTEN,		/* page writings since bootup */
+	NR_METADATA_DIRTY_BYTES,	/* Metadata dirty bytes */
+	NR_METADATA_WRITEBACK_BYTES,	/* Metadata writeback bytes */
+	NR_METADATA_BYTES,	/* total metadata bytes in use. */
 	NR_VM_NODE_STAT_ITEMS
 };
 
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 7bd8783a590f..372feb725a00 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -390,6 +390,8 @@ TRACE_EVENT(writeback_queue_io,
 	)
 );
 
+#define BtoP(x) ((x) >> PAGE_SHIFT)
+
 TRACE_EVENT(global_dirty_state,
 
 	TP_PROTO(unsigned long background_thresh,
@@ -402,7 +404,9 @@ TRACE_EVENT(global_dirty_state,
 
 	TP_STRUCT__entry(
 		__field(unsigned long,	nr_dirty)
+		__field(unsigned long,	nr_metadata_dirty)
 		__field(unsigned long,	nr_writeback)
+		__field(unsigned long,	nr_metadata_writeback)
 		__field(unsigned long,	nr_unstable)
 		__field(unsigned long,	background_thresh)
 		__field(unsigned long,	dirty_thresh)
@@ -413,7 +417,9 @@ TRACE_EVENT(global_dirty_state,
 
 	TP_fast_assign(
 		__entry->nr_dirty	= global_node_page_state(NR_FILE_DIRTY);
+		__entry->nr_metadata_dirty = BtoP(global_node_page_state(NR_METADATA_DIRTY_BYTES));
 		__entry->nr_writeback	= global_node_page_state(NR_WRITEBACK);
+		__entry->nr_metadata_dirty = BtoP(global_node_page_state(NR_METADATA_WRITEBACK_BYTES));
 		__entry->nr_unstable	= global_node_page_state(NR_UNSTABLE_NFS);
 		__entry->nr_dirtied	= global_node_page_state(NR_DIRTIED);
 		__entry->nr_written	= global_node_page_state(NR_WRITTEN);
@@ -424,7 +430,8 @@ TRACE_EVENT(global_dirty_state,
 
 	TP_printk("dirty=%lu writeback=%lu unstable=%lu "
 		  "bg_thresh=%lu thresh=%lu limit=%lu "
-		  "dirtied=%lu written=%lu",
+		  "dirtied=%lu written=%lu metadata_dirty=%lu "
+		  "metadata_writeback=%lu",
 		  __entry->nr_dirty,
 		  __entry->nr_writeback,
 		  __entry->nr_unstable,
@@ -432,7 +439,9 @@ TRACE_EVENT(global_dirty_state,
 		  __entry->dirty_thresh,
 		  __entry->dirty_limit,
 		  __entry->nr_dirtied,
-		  __entry->nr_written
+		  __entry->nr_written,
+		  __entry->nr_metadata_dirty,
+		  __entry->nr_metadata_writeback
 	)
 );
 
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 2eef55428654..b4fbe1c015ae 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -76,6 +76,8 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 		   "BackgroundThresh:   %10lu kB\n"
 		   "BdiDirtiedBytes:    %10lu kB\n"
 		   "BdiWrittenBytes:    %10lu kB\n"
+		   "BdiMetadataDirty:   %10lu kB\n"
+		   "BdiMetaWriteback:	%10lu kB\n"
 		   "BdiWriteBandwidth:  %10lu kBps\n"
 		   "b_dirty:            %10lu\n"
 		   "b_io:               %10lu\n"
@@ -90,6 +92,8 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
 		   PtoK(background_thresh),
 		   (unsigned long) BtoK(wb_stat(wb, WB_DIRTIED_BYTES)),
 		   (unsigned long) BtoK(wb_stat(wb, WB_WRITTEN_BYTES)),
+		   (unsigned long) BtoK(wb_stat(wb, WB_METADATA_DIRTY_BYTES)),
+		   (unsigned long) BtoK(wb_stat(wb, WB_METADATA_WRITEBACK_BYTES)),
 		   (unsigned long) PtoK(wb->write_bandwidth),
 		   nr_dirty,
 		   nr_io,
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7e9fa012797f..62da1c255945 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -297,6 +297,7 @@ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
 
 	nr_pages += node_page_state(pgdat, NR_INACTIVE_FILE);
 	nr_pages += node_page_state(pgdat, NR_ACTIVE_FILE);
+	nr_pages += node_page_state(pgdat, NR_METADATA_BYTES) >> PAGE_SHIFT;
 
 	return nr_pages;
 }
@@ -373,6 +374,7 @@ static unsigned long global_dirtyable_memory(void)
 
 	x += global_node_page_state(NR_INACTIVE_FILE);
 	x += global_node_page_state(NR_ACTIVE_FILE);
+	x += global_node_page_state(NR_METADATA_BYTES) >> PAGE_SHIFT;
 
 	if (!vm_highmem_is_dirtyable)
 		x -= highmem_dirtyable_memory(x);
@@ -381,6 +383,30 @@ static unsigned long global_dirtyable_memory(void)
 }
 
 /**
+ * global_dirty_memory - the number of globally dirty pages
+ *
+ * Returns the global number of pages that are dirty in pagecache and metadata.
+ */
+static unsigned long global_dirty_memory(void)
+{
+	return global_node_page_state(NR_FILE_DIRTY) +
+		global_node_page_state(NR_UNSTABLE_NFS) +
+		(global_node_page_state(NR_METADATA_DIRTY_BYTES) >> PAGE_SHIFT);
+}
+
+/**
+ * global_writeback_memory - the number of pages under writeback globally
+ *
+ * Returns the global number of pages under writeback both in pagecache and in
+ * metadata.
+ */
+static unsigned long global_writeback_memory(void)
+{
+	return global_node_page_state(NR_WRITEBACK) +
+		(global_node_page_state(NR_METADATA_WRITEBACK_BYTES) >> PAGE_SHIFT);
+}
+
+/**
  * domain_dirty_limits - calculate thresh and bg_thresh for a wb_domain
  * @dtc: dirty_throttle_control of interest
  *
@@ -1514,7 +1540,7 @@ static long wb_min_pause(struct bdi_writeback *wb,
 static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
 {
 	struct bdi_writeback *wb = dtc->wb;
-	unsigned long wb_reclaimable;
+	unsigned long wb_reclaimable, wb_writeback;
 
 	/*
 	 * wb_thresh is not treated as some limiting factor as
@@ -1544,12 +1570,17 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
 	 * deltas.
 	 */
 	if (dtc->wb_thresh < 2 * wb_stat_error(wb)) {
-		wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE);
-		dtc->wb_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
+		wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE) +
+			(wb_stat_sum(wb, WB_METADATA_DIRTY_BYTES) >> PAGE_SHIFT);
+		wb_writeback = wb_stat_sum(wb, WB_WRITEBACK) +
+			(wb_stat_sum(wb, WB_METADATA_WRITEBACK_BYTES) >> PAGE_SHIFT);
 	} else {
-		wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE);
-		dtc->wb_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
+		wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE) +
+			(wb_stat(wb, WB_METADATA_DIRTY_BYTES) >> PAGE_SHIFT);
+		wb_writeback = wb_stat(wb, WB_WRITEBACK) +
+			(wb_stat(wb, WB_METADATA_WRITEBACK_BYTES) >> PAGE_SHIFT);
 	}
+	dtc->wb_dirty = wb_reclaimable + wb_writeback;
 }
 
 /*
@@ -1594,10 +1625,9 @@ static void balance_dirty_pages(struct bdi_writeback *wb,
 		 * written to the server's write cache, but has not yet
 		 * been flushed to permanent storage.
 		 */
-		nr_reclaimable = global_node_page_state(NR_FILE_DIRTY) +
-					global_node_page_state(NR_UNSTABLE_NFS);
+		nr_reclaimable = global_dirty_memory();
 		gdtc->avail = global_dirtyable_memory();
-		gdtc->dirty = nr_reclaimable + global_node_page_state(NR_WRITEBACK);
+		gdtc->dirty = nr_reclaimable + global_writeback_memory();
 
 		domain_dirty_limits(gdtc);
 
@@ -1929,20 +1959,22 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
 	struct dirty_throttle_control * const gdtc = &gdtc_stor;
 	struct dirty_throttle_control * const mdtc = mdtc_valid(&mdtc_stor) ?
 						     &mdtc_stor : NULL;
+	unsigned long wb_reclaimable;
 
 	/*
 	 * Similar to balance_dirty_pages() but ignores pages being written
 	 * as we're trying to decide whether to put more under writeback.
 	 */
 	gdtc->avail = global_dirtyable_memory();
-	gdtc->dirty = global_node_page_state(NR_FILE_DIRTY) +
-		      global_node_page_state(NR_UNSTABLE_NFS);
+	gdtc->dirty = global_dirty_memory();
 	domain_dirty_limits(gdtc);
 
 	if (gdtc->dirty > gdtc->bg_thresh)
 		return true;
 
-	if (wb_stat(wb, WB_RECLAIMABLE) >
+	wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE) +
+		(wb_stat(wb, WB_METADATA_DIRTY_BYTES) >> PAGE_SHIFT);
+	if (wb_reclaimable >
 	    wb_calc_thresh(gdtc->wb, gdtc->bg_thresh))
 		return true;
 
@@ -1957,7 +1989,7 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
 		if (mdtc->dirty > mdtc->bg_thresh)
 			return true;
 
-		if (wb_stat(wb, WB_RECLAIMABLE) >
+		if (wb_reclaimable >
 		    wb_calc_thresh(mdtc->wb, mdtc->bg_thresh))
 			return true;
 	}
@@ -1979,8 +2011,7 @@ int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
 void laptop_mode_timer_fn(unsigned long data)
 {
 	struct request_queue *q = (struct request_queue *)data;
-	int nr_pages = global_node_page_state(NR_FILE_DIRTY) +
-		global_node_page_state(NR_UNSTABLE_NFS);
+	int nr_pages = global_dirty_memory();
 	struct bdi_writeback *wb;
 
 	/*
@@ -2446,6 +2477,104 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 EXPORT_SYMBOL(account_page_dirtied);
 
 /*
+ * account_metadata_dirtied
+ * @page - the page being dirited
+ * @bdi - the bdi that owns this page
+ * @bytes - the number of bytes being dirtied
+ *
+ * Do the dirty page accounting for metadata pages that aren't backed by an
+ * address_space.
+ */
+void account_metadata_dirtied(struct page *page, struct backing_dev_info *bdi,
+			      long bytes)
+{
+	unsigned long flags;
+
+	__add_wb_stat(&bdi->wb, WB_DIRTIED_BYTES, bytes);
+	__add_wb_stat(&bdi->wb, WB_METADATA_DIRTY_BYTES, bytes);
+
+	local_irq_save(flags);
+	__mod_node_page_state(page_pgdat(page), NR_METADATA_DIRTY_BYTES,
+			      bytes);
+	current->nr_dirtied++;
+	task_io_account_write(bytes);
+	this_cpu_inc(bdp_ratelimits);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(account_metadata_dirtied);
+
+/*
+ * account_metadata_cleaned
+ * @page - the page being cleaned
+ * @bdi - the bdi that owns this page
+ * @bytes - the number of bytes cleaned
+ *
+ * Called on a no longer dirty metadata page.
+ */
+void account_metadata_cleaned(struct page *page, struct backing_dev_info *bdi,
+			      long bytes)
+{
+	unsigned long flags;
+
+	__add_wb_stat(&bdi->wb, WB_METADATA_DIRTY_BYTES, -bytes);
+
+	local_irq_save(flags);
+	__mod_node_page_state(page_pgdat(page), NR_METADATA_DIRTY_BYTES,
+			      -bytes);
+	task_io_account_cancelled_write(bytes);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(account_metadata_cleaned);
+
+/*
+ * account_metadata_writeback
+ * @page - the page being marked as writeback
+ * @bdi - the bdi that owns this page
+ * @bytes - the number of bytes we are submitting for writeback
+ *
+ * Called on a metadata page that has been marked writeback.
+ */
+void account_metadata_writeback(struct page *page,
+				struct backing_dev_info *bdi, long bytes)
+{
+	unsigned long flags;
+
+	__add_wb_stat(&bdi->wb, WB_METADATA_DIRTY_BYTES, -bytes);
+	__add_wb_stat(&bdi->wb, WB_METADATA_WRITEBACK_BYTES, bytes);
+
+	local_irq_save(flags);
+	__mod_node_page_state(page_pgdat(page), NR_METADATA_DIRTY_BYTES,
+					 -bytes);
+	__mod_node_page_state(page_pgdat(page), NR_METADATA_WRITEBACK_BYTES,
+					 bytes);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(account_metadata_writeback);
+
+/*
+ * account_metadata_end_writeback
+ * @page - the page we are ending writeback on
+ * @bdi - the bdi that owns this page
+ * @bytes - the number of bytes that just ended writeback
+ *
+ * Called on a metadata page that has completed writeback.
+ */
+void account_metadata_end_writeback(struct page *page,
+				    struct backing_dev_info *bdi, long bytes)
+{
+	unsigned long flags;
+
+	__add_wb_stat(&bdi->wb, WB_METADATA_WRITEBACK_BYTES, -bytes);
+
+	local_irq_save(flags);
+	__mod_node_page_state(page_pgdat(page), NR_METADATA_WRITEBACK_BYTES,
+					 -bytes);
+	__wb_writeout_add(&bdi->wb, bytes);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(account_metadata_end_writeback);
+
+/*
  * Helper function for deaccounting dirty page without writeback.
  *
  * Caller must hold lock_page_memcg().
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5785a2f8d7db..a59912f0a16e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4460,6 +4460,9 @@ static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask
 	return !node_isset(nid, *nodemask);
 }
 
+#define BtoK(x) ((x) >> 10)
+#define BtoP(x) ((x) >> PAGE_SHIFT)
+
 static void show_migration_types(unsigned char type)
 {
 	static const char types[MIGRATE_TYPES] = {
@@ -4513,10 +4516,11 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 
 	printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
 		" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
-		" unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
-		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
-		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
-		" free:%lu free_pcp:%lu free_cma:%lu\n",
+		" unevictable:%lu metadata:%lu dirty:%lu metadata_dirty:%lu\n"
+		" writeback:%lu unstable:%lu metadata_writeback:%lu\n"
+		" slab_reclaimable:%lu slab_unreclaimable:%lu mapped:%lu\n"
+		" shmem:%lu pagetables:%lu bounce:%lu free:%lu free_pcp:%lu\n"
+	        " free_cma:%lu\n",
 		global_node_page_state(NR_ACTIVE_ANON),
 		global_node_page_state(NR_INACTIVE_ANON),
 		global_node_page_state(NR_ISOLATED_ANON),
@@ -4524,9 +4528,12 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		global_node_page_state(NR_INACTIVE_FILE),
 		global_node_page_state(NR_ISOLATED_FILE),
 		global_node_page_state(NR_UNEVICTABLE),
+		BtoP(global_node_page_state(NR_METADATA_BYTES)),
 		global_node_page_state(NR_FILE_DIRTY),
+		BtoP(global_node_page_state(NR_METADATA_DIRTY_BYTES)),
 		global_node_page_state(NR_WRITEBACK),
 		global_node_page_state(NR_UNSTABLE_NFS),
+		BtoP(global_node_page_state(NR_METADATA_WRITEBACK_BYTES)),
 		global_page_state(NR_SLAB_RECLAIMABLE),
 		global_page_state(NR_SLAB_UNRECLAIMABLE),
 		global_node_page_state(NR_FILE_MAPPED),
@@ -4549,9 +4556,12 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 			" unevictable:%lukB"
 			" isolated(anon):%lukB"
 			" isolated(file):%lukB"
+			" metadata:%lukB"
 			" mapped:%lukB"
 			" dirty:%lukB"
+			" metadata_dirty:%lukB"
 			" writeback:%lukB"
+			" metadata_writeback:%lukB"
 			" shmem:%lukB"
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			" shmem_thp: %lukB"
@@ -4570,9 +4580,12 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 			PtoK(node_page_state(pgdat, NR_UNEVICTABLE)),
 			PtoK(node_page_state(pgdat, NR_ISOLATED_ANON)),
 			PtoK(node_page_state(pgdat, NR_ISOLATED_FILE)),
+			BtoK(node_page_state(pgdat, NR_METADATA_BYTES)),
 			PtoK(node_page_state(pgdat, NR_FILE_MAPPED)),
 			PtoK(node_page_state(pgdat, NR_FILE_DIRTY)),
+			BtoK(node_page_state(pgdat, NR_METADATA_DIRTY_BYTES)),
 			PtoK(node_page_state(pgdat, NR_WRITEBACK)),
+			BtoK(node_page_state(pgdat, NR_METADATA_WRITEBACK_BYTES)),
 			PtoK(node_page_state(pgdat, NR_SHMEM)),
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			PtoK(node_page_state(pgdat, NR_SHMEM_THPS) *
diff --git a/mm/util.c b/mm/util.c
index 26be6407abd7..c7f4e8f4ff71 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -617,6 +617,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 		 */
 		free += global_page_state(NR_SLAB_RECLAIMABLE);
 
+		free += global_page_state(NR_METADATA_BYTES) >> PAGE_SHIFT;
+
 		/*
 		 * Leave reserved pages. The pages are not for anonymous pages.
 		 */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8ad39bbc79e6..651a2279a0b5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -225,7 +225,8 @@ unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat)
 
 	nr = node_page_state_snapshot(pgdat, NR_ACTIVE_FILE) +
 	     node_page_state_snapshot(pgdat, NR_INACTIVE_FILE) +
-	     node_page_state_snapshot(pgdat, NR_ISOLATED_FILE);
+	     node_page_state_snapshot(pgdat, NR_ISOLATED_FILE) +
+	     (node_page_state_snapshot(pgdat, NR_METADATA_BYTES) >> PAGE_SHIFT);
 
 	if (get_nr_swap_pages() > 0)
 		nr += node_page_state_snapshot(pgdat, NR_ACTIVE_ANON) +
@@ -3741,6 +3742,7 @@ static inline unsigned long node_unmapped_file_pages(struct pglist_data *pgdat)
 static unsigned long node_pagecache_reclaimable(struct pglist_data *pgdat)
 {
 	unsigned long nr_pagecache_reclaimable;
+	unsigned long nr_metadata_reclaimable;
 	unsigned long delta = 0;
 
 	/*
@@ -3762,7 +3764,20 @@ static unsigned long node_pagecache_reclaimable(struct pglist_data *pgdat)
 	if (unlikely(delta > nr_pagecache_reclaimable))
 		delta = nr_pagecache_reclaimable;
 
-	return nr_pagecache_reclaimable - delta;
+	nr_metadata_reclaimable =
+		node_page_state(pgdat, NR_METADATA_BYTES) >> PAGE_SHIFT;
+	/*
+	 * We don't do writeout through the shrinkers so subtract any
+	 * dirty/writeback metadata bytes from the reclaimable count.
+	 */
+	if (nr_metadata_reclaimable) {
+		unsigned long unreclaimable =
+			node_page_state(pgdat, NR_METADATA_DIRTY_BYTES) +
+			node_page_state(pgdat, NR_METADATA_WRITEBACK_BYTES);
+		unreclaimable >>= PAGE_SHIFT;
+		nr_metadata_reclaimable -= unreclaimable;
+	}
+	return nr_metadata_reclaimable + nr_pagecache_reclaimable - delta;
 }
 
 /*
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 76f73670200a..0383cfd4320b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -972,6 +972,9 @@ const char * const vmstat_text[] = {
 	"nr_vmscan_immediate_reclaim",
 	"nr_dirtied",
 	"nr_written",
+	"nr_metadata_dirty_bytes",
+	"nr_metadata_writeback_bytes",
+	"nr_metadata_bytes",
 
 	/* enum writeback_stat_item counters */
 	"nr_dirty_threshold",
-- 
2.7.4

Powered by blists - more mailing lists