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Commit 604ea906 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm thin: adjust max_sectors_kb based on thinp blocksize 



Allows for filesystems to submit bios that are a factor of the thinp
blocksize, improving dm-thinp efficiency (particularly when the data
volume is RAID).

Also set io_min to max_sectors_kb if it is a factor of the thinp
blocksize.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 7d327fe0

drivers/md/dm-thin.c

+31 −3
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/device-mapper.h>

#include <linux/dm-io.h>

#include <linux/dm-kcopyd.h>

#include <linux/log2.h>

#include <linux/list.h>

#include <linux/rculist.h>

#include <linux/init.h>
@@ -3242,14 +3243,41 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) 
{

	struct pool_c *pt = ti->private;

	struct pool *pool = pt->pool;

	uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;

	sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;



	/*

	 * Adjust max_sectors_kb to highest possible power-of-2

	 * factor of pool->sectors_per_block.

	 */

	if (limits->max_hw_sectors & (limits->max_hw_sectors - 1))

		limits->max_sectors = rounddown_pow_of_two(limits->max_hw_sectors);

	else

		limits->max_sectors = limits->max_hw_sectors;



	if (limits->max_sectors < pool->sectors_per_block) {

		while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {

			if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)

				limits->max_sectors--;

			limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);

		}

	} else if (block_size_is_power_of_two(pool)) {

		/* max_sectors_kb is >= power-of-2 thinp blocksize */

		while (!is_factor(limits->max_sectors, pool->sectors_per_block)) {

			if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)

				limits->max_sectors--;

			limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);

		}

	}



	/*

	 * If the system-determined stacked limits are compatible with the

	 * pool's blocksize (io_opt is a factor) do not override them.

	 */

	if (io_opt_sectors < pool->sectors_per_block ||

	    do_div(io_opt_sectors, pool->sectors_per_block)) {

	    !is_factor(io_opt_sectors, pool->sectors_per_block)) {

		if (is_factor(pool->sectors_per_block, limits->max_sectors))

			blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);

		else

			blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);

		blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);

	}