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Commit 1edf2234 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm/page-writeback.c: make determine_dirtyable_memory static again 



The tracing ring-buffer used this function briefly, but not anymore.
Make it local to the writeback code again.

Also, move the function so that no forward declaration needs to be
reintroduced.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e4e11180

include/linux/writeback.h

+0 −2
Original line number Diff line number Diff line
@@ -138,8 +138,6 @@ extern int vm_highmem_is_dirtyable; 
extern int block_dump;

extern int laptop_mode;



extern unsigned long determine_dirtyable_memory(void);



extern int dirty_background_ratio_handler(struct ctl_table *table, int write,

		void __user *buffer, size_t *lenp,

		loff_t *ppos);

mm/page-writeback.c

+60 −62
Original line number Diff line number Diff line
@@ -129,6 +129,66 @@ unsigned long global_dirty_limit; 
 */

static struct prop_descriptor vm_completions;



/*

 * Work out the current dirty-memory clamping and background writeout

 * thresholds.

 *

 * The main aim here is to lower them aggressively if there is a lot of mapped

 * memory around.  To avoid stressing page reclaim with lots of unreclaimable

 * pages.  It is better to clamp down on writers than to start swapping, and

 * performing lots of scanning.

 *

 * We only allow 1/2 of the currently-unmapped memory to be dirtied.

 *

 * We don't permit the clamping level to fall below 5% - that is getting rather

 * excessive.

 *

 * We make sure that the background writeout level is below the adjusted

 * clamping level.

 */

static unsigned long highmem_dirtyable_memory(unsigned long total)

{

#ifdef CONFIG_HIGHMEM

	int node;

	unsigned long x = 0;



	for_each_node_state(node, N_HIGH_MEMORY) {

		struct zone *z =

			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];



		x += zone_page_state(z, NR_FREE_PAGES) +

		     zone_reclaimable_pages(z);

	}

	/*

	 * Make sure that the number of highmem pages is never larger

	 * than the number of the total dirtyable memory. This can only

	 * occur in very strange VM situations but we want to make sure

	 * that this does not occur.

	 */

	return min(x, total);

#else

	return 0;

#endif

}



/**

 * determine_dirtyable_memory - amount of memory that may be used

 *

 * Returns the numebr of pages that can currently be freed and used

 * by the kernel for direct mappings.

 */

static unsigned long determine_dirtyable_memory(void)

{

	unsigned long x;



	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();



	if (!vm_highmem_is_dirtyable)

		x -= highmem_dirtyable_memory(x);



	return x + 1;	/* Ensure that we never return 0 */

}



/*

 * couple the period to the dirty_ratio:

 *
@@ -196,7 +256,6 @@ int dirty_ratio_handler(struct ctl_table *table, int write, 
	return ret;

}





int dirty_bytes_handler(struct ctl_table *table, int write,

		void __user *buffer, size_t *lenp,

		loff_t *ppos)
@@ -291,67 +350,6 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio) 
}

EXPORT_SYMBOL(bdi_set_max_ratio);



/*

 * Work out the current dirty-memory clamping and background writeout

 * thresholds.

 *

 * The main aim here is to lower them aggressively if there is a lot of mapped

 * memory around.  To avoid stressing page reclaim with lots of unreclaimable

 * pages.  It is better to clamp down on writers than to start swapping, and

 * performing lots of scanning.

 *

 * We only allow 1/2 of the currently-unmapped memory to be dirtied.

 *

 * We don't permit the clamping level to fall below 5% - that is getting rather

 * excessive.

 *

 * We make sure that the background writeout level is below the adjusted

 * clamping level.

 */



static unsigned long highmem_dirtyable_memory(unsigned long total)

{

#ifdef CONFIG_HIGHMEM

	int node;

	unsigned long x = 0;



	for_each_node_state(node, N_HIGH_MEMORY) {

		struct zone *z =

			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];



		x += zone_page_state(z, NR_FREE_PAGES) +

		     zone_reclaimable_pages(z);

	}

	/*

	 * Make sure that the number of highmem pages is never larger

	 * than the number of the total dirtyable memory. This can only

	 * occur in very strange VM situations but we want to make sure

	 * that this does not occur.

	 */

	return min(x, total);

#else

	return 0;

#endif

}



/**

 * determine_dirtyable_memory - amount of memory that may be used

 *

 * Returns the numebr of pages that can currently be freed and used

 * by the kernel for direct mappings.

 */

unsigned long determine_dirtyable_memory(void)

{

	unsigned long x;



	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();



	if (!vm_highmem_is_dirtyable)

		x -= highmem_dirtyable_memory(x);



	return x + 1;	/* Ensure that we never return 0 */

}



static unsigned long dirty_freerun_ceiling(unsigned long thresh,

					   unsigned long bg_thresh)

{