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From: Johannes Weiner <hannes@cmpxchg.org>
To: Josef Bacik <jbacik@fb.com>
Cc: linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	kernel-team@fb.com, jack@suse.com, viro@zeniv.linux.org.uk,
	dchinner@redhat.com, hch@lst.de, linux-mm@kvack.org
Subject: Re: [PATCH 2/4] writeback: allow for dirty metadata accounting
Date: Thu, 22 Sep 2016 15:48:29 -0400	[thread overview]
Message-ID: <20160922194829.GB6054@cmpxchg.org> (raw)
In-Reply-To: <1474405068-27841-3-git-send-email-jbacik@fb.com>

Hi Josef,

as we talked off line, I think the idea of maintaining a byte counter
and rounding in balance_dirty_pages() is the best way to do this. And
Jan spotted all the actual bugs, so I only have a few nitpicks :)

On Tue, Sep 20, 2016 at 04:57:46PM -0400, Josef Bacik wrote:
> @@ -44,12 +44,13 @@ void show_mem(unsigned int filter)
>  {
>  	struct zone *zone;
>  
> -	pr_err("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu free:%lu\n slab:%lu mapped:%lu pagetables:%lu bounce:%lu pagecache:%lu swap:%lu\n",
> +	pr_err("Active:%lu inactive:%lu dirty:%lu metadata_dirty:%lu writeback:%lu unstable:%lu free:%lu\n slab:%lu mapped:%lu pagetables:%lu bounce:%lu pagecache:%lu swap:%lu\n",
>  	       (global_node_page_state(NR_ACTIVE_ANON) +
>  		global_node_page_state(NR_ACTIVE_FILE)),
>  	       (global_node_page_state(NR_INACTIVE_ANON) +
>  		global_node_page_state(NR_INACTIVE_FILE)),
>  	       global_node_page_state(NR_FILE_DIRTY),
> +	       global_node_page_state(NR_METADATA_DIRTY),
>  	       global_node_page_state(NR_WRITEBACK),

Print NR_METADATA_WRITEBACK here as well?

> @@ -51,6 +51,8 @@ static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
>  static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);
>  
>  #define K(x) ((x) << (PAGE_SHIFT - 10))
> +#define BtoK(x) ((x) >> 10)
> +
>  static ssize_t node_read_meminfo(struct device *dev,
>  			struct device_attribute *attr, char *buf)
>  {
> @@ -99,7 +101,9 @@ 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"

Between the enums and stat printing, the naming is kind of all over
the place. How about NR_META_DIRTY_BYTES and NR_META_WRITEBACK_BYTES
as a separate group than the existing dirty & writeback stats?

 	n += sprintf(buf + n,
 		       "Node %d Dirty:          %8lu kB\n"
 		       "Node %d Writeback:      %8lu kB\n"
+		       "Node %d MetaDirty:	%8lu kB\n"
+		       "Node %d MetaWriteback:  %8lu kB\n"

>  		       "Node %d FilePages:      %8lu kB\n"
>  		       "Node %d Mapped:         %8lu kB\n"
>  		       "Node %d AnonPages:      %8lu kB\n"
> @@ -119,7 +123,9 @@ static ssize_t node_read_meminfo(struct device *dev,
>  #endif
>  			,
>  		       nid, K(node_page_state(pgdat, NR_FILE_DIRTY)),
> +		       nid, BtoK(node_page_state(pgdat, NR_METADATA_DIRTY_BYTES)),
>  		       nid, K(node_page_state(pgdat, NR_WRITEBACK)),
> +		       nid, BtoK(node_page_state(pgdat, NR_METADATA_WRITEBACK_BYTES)),
>  		       nid, K(node_page_state(pgdat, NR_FILE_PAGES)),
>  		       nid, K(node_page_state(pgdat, NR_FILE_MAPPED)),
>  		       nid, K(node_page_state(pgdat, NR_ANON_MAPPED)),
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 56c8fda..aafdb11 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -1801,6 +1801,7 @@ static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb)
>  	return work;
>  }
>  
> +#define BtoP(x) ((x) >> PAGE_SHIFT)

Might be more readable inline:

> @@ -1809,6 +1810,7 @@ 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)) +

		global_node_page_state(NR_META_DIRTY_BYTES) / PAGE_SIZE +

>  		get_nr_dirty_inodes();
>  }

> @@ -80,7 +81,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
>  		"SwapTotal:      %8lu kB\n"
>  		"SwapFree:       %8lu kB\n"
>  		"Dirty:          %8lu kB\n"
> +		"MetadataDirty:  %8lu kB\n"
>  		"Writeback:      %8lu kB\n"
> +		"MetaWriteback:  %8lu kB\n"

 		"Dirty:          %8lu kB\n"
 		"Writeback:      %8lu kB\n"
+		"MetaDirty:      %8lu kB\n"
+		"MetaWriteback:  %8lu kB\n"


>  		"AnonPages:      %8lu kB\n"
>  		"Mapped:         %8lu kB\n"
>  		"Shmem:          %8lu kB\n"
> @@ -139,7 +142,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
>  		K(i.totalswap),
>  		K(i.freeswap),
>  		K(global_node_page_state(NR_FILE_DIRTY)),
> +		BtoK(global_node_page_state(NR_METADATA_DIRTY_BYTES)),
>  		K(global_node_page_state(NR_WRITEBACK)),
> +		BtoK(global_node_page_state(NR_META_WRITEBACK_BYTES)),

		K(global_node_page_state(NR_META_WRITEBACK_BYTES / PAGE_SIZE)),

and drop BtoK?

> @@ -34,6 +34,8 @@ typedef int (congested_fn)(void *, int);
>  enum wb_stat_item {
>  	WB_RECLAIMABLE,
>  	WB_WRITEBACK,
> +	WB_METADATA_DIRTY_BYTES,
> +	WB_METADATA_WRITEBACK_BYTES,

	WB_META_DIRTY_BYTES,
	WB_META_WRITEBACK_BYTES,

etc.

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  parent reply	other threads:[~2016-09-22 19:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-20 20:57 [PATCH 0/4][V3] metadata throttling in writeback patches Josef Bacik
2016-09-20 20:57 ` [PATCH 1/4] remove mapping from balance_dirty_pages*() Josef Bacik
2016-09-20 20:57 ` [PATCH 2/4] writeback: allow for dirty metadata accounting Josef Bacik
2016-09-22 11:18   ` Jan Kara
2016-09-22 13:34     ` Josef Bacik
2016-09-22 19:48   ` Johannes Weiner [this message]
2016-09-20 20:57 ` [PATCH 3/4] writeback: convert WB_WRITTEN/WB_DIRITED counters to bytes Josef Bacik
2016-09-22 11:34   ` Jan Kara
2016-09-22 13:35     ` Josef Bacik
2016-09-20 20:57 ` [PATCH 4/4] writeback: introduce super_operations->write_metadata Josef Bacik
2016-09-22 11:48   ` Jan Kara
2016-09-22 13:36     ` Josef Bacik
2017-11-08 19:00 [PATCH 1/4] remove mapping from balance_dirty_pages*() Josef Bacik
2017-11-08 19:00 ` [PATCH 2/4] writeback: allow for dirty metadata accounting Josef Bacik
2017-11-09 10:32   ` Jan Kara
2017-11-09 14:28     ` Josef Bacik

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