Commit 33863c21 authored by Nitin Gupta's avatar Nitin Gupta Committed by Greg Kroah-Hartman
Browse files

Staging: zram: Replace ioctls with sysfs interface 



Creates per-device sysfs nodes in /sys/block/zram<id>/
Currently following stats are exported:
 - disksize
 - num_reads
 - num_writes
 - invalid_io
 - zero_pages
 - orig_data_size
 - compr_data_size
 - mem_used_total

By default, disksize is set to 0. So, to start using
a zram device, fist write a disksize value and then
initialize device by writing any positive value to
initstate. For example:

        # initialize /dev/zram0 with 50MB disksize
        echo 50*1024*1024 | bc > /sys/block/zram0/disksize
        echo 1 > /sys/block/zram0/initstate

When done using a disk, issue reset to free its memory
by writing any positive value to reset node:

        echo 1 > /sys/block/zram0/reset

This change also obviates the need for 'rzscontrol' utility.

Signed-off-by: default avatarNitin Gupta <ngupta@vflare.org>
Acked-by: default avatarPekka Enberg <penberg@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e1a164d7

drivers/staging/zram/Kconfig

+0 −12
Original line number Diff line number Diff line
@@ -15,15 +15,3 @@ config ZRAM 


	  See zram.txt for more information.

	  Project home: http://compcache.googlecode.com/
 


config ZRAM_STATS

	bool "Enable statistics for compressed RAM disks"

	depends on ZRAM

	default y

	help

	  Enable statistics collection for compressed RAM devices. Statistics

	  are exported through ioctl interface, so you have to use zramconfig

	  program to get them. This adds only a minimal overhead.



	  If unsure, say Y.

drivers/staging/zram/Makefile

+1 −1
Original line number Diff line number Diff line 
zram-objs	:=	zram_drv.o xvmalloc.o

zram-objs	:=	zram_drv.o zram_sysfs.o xvmalloc.o



obj-$(CONFIG_ZRAM)	+=	zram.o

drivers/staging/zram/zram_drv.c

+53 −133
Original line number Diff line number Diff line
@@ -33,10 +33,39 @@ 


/* Globals */

static int zram_major;

static struct zram *devices;

struct zram *devices;



/* Module params (documentation at end) */

static unsigned int num_devices;

unsigned int num_devices;



static void zram_stat_inc(u32 *v)

{

	*v = *v + 1;

}



static void zram_stat_dec(u32 *v)

{

	*v = *v - 1;

}



static void zram_stat64_add(struct zram *zram, u64 *v, u64 inc)

{

	spin_lock(&zram->stat64_lock);

	*v = *v + inc;

	spin_unlock(&zram->stat64_lock);

}



static void zram_stat64_sub(struct zram *zram, u64 *v, u64 dec)

{

	spin_lock(&zram->stat64_lock);

	*v = *v - dec;

	spin_unlock(&zram->stat64_lock);

}



static void zram_stat64_inc(struct zram *zram, u64 *v)

{

	zram_stat64_add(zram, v, 1);

}



static int zram_test_flag(struct zram *zram, u32 index,

			enum zram_pageflags flag)
@@ -91,7 +120,7 @@ static void zram_set_disksize(struct zram *zram, size_t totalram_bytes) 
		"the disk when not in use so a huge zram is "

		"wasteful.\n"

		"\tMemory Size: %zu kB\n"

		"\tSize you selected: %zu kB\n"

		"\tSize you selected: %llu kB\n"

		"Continuing anyway ...\n",

		totalram_bytes >> 10, zram->disksize

		);
@@ -100,49 +129,6 @@ static void zram_set_disksize(struct zram *zram, size_t totalram_bytes) 
	zram->disksize &= PAGE_MASK;

}



static void zram_ioctl_get_stats(struct zram *zram,

			struct zram_ioctl_stats *s)

{

	s->disksize = zram->disksize;



#if defined(CONFIG_ZRAM_STATS)

	{

	struct zram_stats *rs = &zram->stats;

	size_t succ_writes, mem_used;

	unsigned int good_compress_perc = 0, no_compress_perc = 0;



	mem_used = xv_get_total_size_bytes(zram->mem_pool)

			+ (rs->pages_expand << PAGE_SHIFT);

	succ_writes = zram_stat64_read(zram, &rs->num_writes) -

			zram_stat64_read(zram, &rs->failed_writes);



	if (succ_writes && rs->pages_stored) {

		good_compress_perc = rs->good_compress * 100

					/ rs->pages_stored;

		no_compress_perc = rs->pages_expand * 100

					/ rs->pages_stored;

	}



	s->num_reads = zram_stat64_read(zram, &rs->num_reads);

	s->num_writes = zram_stat64_read(zram, &rs->num_writes);

	s->failed_reads = zram_stat64_read(zram, &rs->failed_reads);

	s->failed_writes = zram_stat64_read(zram, &rs->failed_writes);

	s->invalid_io = zram_stat64_read(zram, &rs->invalid_io);

	s->notify_free = zram_stat64_read(zram, &rs->notify_free);

	s->pages_zero = rs->pages_zero;



	s->good_compress_pct = good_compress_perc;

	s->pages_expand_pct = no_compress_perc;



	s->pages_stored = rs->pages_stored;

	s->pages_used = mem_used >> PAGE_SHIFT;

	s->orig_data_size = rs->pages_stored << PAGE_SHIFT;

	s->compr_data_size = rs->compr_size;

	s->mem_used_total = mem_used;

	}

#endif /* CONFIG_ZRAM_STATS */

}



static void zram_free_page(struct zram *zram, size_t index)

{

	u32 clen;
@@ -180,7 +166,7 @@ static void zram_free_page(struct zram *zram, size_t index) 
		zram_stat_dec(&zram->stats.good_compress);



out:

	zram->stats.compr_size -= clen;

	zram_stat64_sub(zram, &zram->stats.compr_size, clen);

	zram_stat_dec(&zram->stats.pages_stored);



	zram->table[index].page = NULL;
@@ -396,7 +382,7 @@ memstore: 
			kunmap_atomic(src, KM_USER0);



		/* Update stats */

		zram->stats.compr_size += clen;

		zram_stat64_add(zram, &zram->stats.compr_size, clen);

		zram_stat_inc(&zram->stats.pages_stored);

		if (clen <= PAGE_SIZE / 2)

			zram_stat_inc(&zram->stats.good_compress);
@@ -463,7 +449,7 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio) 
	return ret;

}



static void reset_device(struct zram *zram)

void zram_reset_device(struct zram *zram)

{

	size_t index;
@@ -506,7 +492,7 @@ static void reset_device(struct zram *zram) 
	zram->disksize = 0;

}



static int zram_ioctl_init_device(struct zram *zram)

int zram_init_device(struct zram *zram)

{

	int ret;

	size_t num_pages;
@@ -561,91 +547,12 @@ static int zram_ioctl_init_device(struct zram *zram) 
	return 0;



fail:

	reset_device(zram);

	zram_reset_device(zram);



	pr_err("Initialization failed: err=%d\n", ret);

	return ret;

}



static int zram_ioctl_reset_device(struct zram *zram)

{

	if (zram->init_done)

		reset_device(zram);



	return 0;

}



static int zram_ioctl(struct block_device *bdev, fmode_t mode,

			unsigned int cmd, unsigned long arg)

{

	int ret = 0;

	size_t disksize_kb;



	struct zram *zram = bdev->bd_disk->private_data;



	switch (cmd) {

	case ZRAMIO_SET_DISKSIZE_KB:

		if (zram->init_done) {

			ret = -EBUSY;

			goto out;

		}

		if (copy_from_user(&disksize_kb, (void *)arg,

						_IOC_SIZE(cmd))) {

			ret = -EFAULT;

			goto out;

		}

		zram->disksize = disksize_kb << 10;

		pr_info("Disk size set to %zu kB\n", disksize_kb);

		break;



	case ZRAMIO_GET_STATS:

	{

		struct zram_ioctl_stats *stats;

		if (!zram->init_done) {

			ret = -ENOTTY;

			goto out;

		}

		stats = kzalloc(sizeof(*stats), GFP_KERNEL);

		if (!stats) {

			ret = -ENOMEM;

			goto out;

		}

		zram_ioctl_get_stats(zram, stats);

		if (copy_to_user((void *)arg, stats, sizeof(*stats))) {

			kfree(stats);

			ret = -EFAULT;

			goto out;

		}

		kfree(stats);

		break;

	}

	case ZRAMIO_INIT:

		ret = zram_ioctl_init_device(zram);

		break;



	case ZRAMIO_RESET:

		/* Do not reset an active device! */

		if (bdev->bd_holders) {

			ret = -EBUSY;

			goto out;

		}



		/* Make sure all pending I/O is finished */

		if (bdev)

			fsync_bdev(bdev);



		ret = zram_ioctl_reset_device(zram);

		break;



	default:

		pr_info("Invalid ioctl %u\n", cmd);

		ret = -ENOTTY;

	}



out:

	return ret;

}



void zram_slot_free_notify(struct block_device *bdev, unsigned long index)

{

	struct zram *zram;
@@ -656,7 +563,6 @@ void zram_slot_free_notify(struct block_device *bdev, unsigned long index) 
}



static const struct block_device_operations zram_devops = {

	.ioctl = zram_ioctl,

	.swap_slot_free_notify = zram_slot_free_notify,

	.owner = THIS_MODULE

};
@@ -696,7 +602,7 @@ static int create_device(struct zram *zram, int device_id) 
	zram->disk->private_data = zram;

	snprintf(zram->disk->disk_name, 16, "zram%d", device_id);



	/* Actual capacity set using ZRAMIO_SET_DISKSIZE_KB ioctl */

	/* Actual capacity set using syfs (/sys/block/zram<id>/disksize */

	set_capacity(zram->disk, 0);



	/*
@@ -710,6 +616,15 @@ static int create_device(struct zram *zram, int device_id) 


	add_disk(zram->disk);



#ifdef CONFIG_SYSFS

	ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,

				&zram_disk_attr_group);

	if (ret < 0) {

		pr_warning("Error creating sysfs group");

		goto out;

	}

#endif



	zram->init_done = 0;



out:
@@ -718,6 +633,11 @@ out: 


static void destroy_device(struct zram *zram)

{

#ifdef CONFIG_SYSFS

	sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,

			&zram_disk_attr_group);

#endif



	if (zram->disk) {

		del_gendisk(zram->disk);

		put_disk(zram->disk);
@@ -785,7 +705,7 @@ static void __exit zram_exit(void) 


		destroy_device(zram);

		if (zram->init_done)

			reset_device(zram);

			zram_reset_device(zram);

	}



	unregister_blkdev(zram_major, "zram");

drivers/staging/zram/zram_drv.h

+10 −45
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ 
#include <linux/spinlock.h>

#include <linux/mutex.h>



#include "zram_ioctl.h"

#include "xvmalloc.h"



/*
@@ -85,11 +84,7 @@ struct table { 
} __attribute__((aligned(4)));



struct zram_stats {

	/* basic stats */

	size_t compr_size;	/* compressed size of pages stored -

				 * needed to enforce memlimit */

	/* more stats */

#if defined(CONFIG_ZRAM_STATS)

	u64 compr_size;		/* compressed size of pages stored */

	u64 num_reads;		/* failed + successful */

	u64 num_writes;		/* --do-- */

	u64 failed_reads;	/* should NEVER! happen */
@@ -100,7 +95,6 @@ struct zram_stats { 
	u32 pages_stored;	/* no. of pages currently stored */

	u32 good_compress;	/* % of pages with compression ratio<=50% */

	u32 pages_expand;	/* % of incompressible pages */

#endif

};



struct zram {
@@ -118,47 +112,18 @@ struct zram { 
	 * This is the limit on amount of *uncompressed* worth of data

	 * we can store in a disk.

	 */

	size_t disksize;	/* bytes */

	u64 disksize;	/* bytes */



	struct zram_stats stats;

};



/*-- */



/* Debugging and Stats */

#if defined(CONFIG_ZRAM_STATS)

static void zram_stat_inc(u32 *v)

{

	*v = *v + 1;

}



static void zram_stat_dec(u32 *v)

{

	*v = *v - 1;

}



static void zram_stat64_inc(struct zram *zram, u64 *v)

{

	spin_lock(&zram->stat64_lock);

	*v = *v + 1;

	spin_unlock(&zram->stat64_lock);

}



static u64 zram_stat64_read(struct zram *zram, u64 *v)

{

	u64 val;



	spin_lock(&zram->stat64_lock);

	val = *v;

	spin_unlock(&zram->stat64_lock);



	return val;

}

#else

#define zram_stat_inc(v)

#define zram_stat_dec(v)

#define zram_stat64_inc(r, v)

#define zram_stat64_read(r, v)

#endif /* CONFIG_ZRAM_STATS */

extern struct zram *devices;

extern unsigned int num_devices;

#ifdef CONFIG_SYSFS

extern struct attribute_group zram_disk_attr_group;

#endif



extern int zram_init_device(struct zram *zram);

extern void zram_reset_device(struct zram *zram);



#endif

drivers/staging/zram/zram_ioctl.h

deleted100644 → 0
+0 −41
Original line number Diff line number Diff line 
/*

 * Compressed RAM block device

 *

 * Copyright (C) 2008, 2009, 2010  Nitin Gupta

 *

 * This code is released using a dual license strategy: BSD/GPL

 * You can choose the licence that better fits your requirements.

 *

 * Released under the terms of 3-clause BSD License

 * Released under the terms of GNU General Public License Version 2.0

 *

 * Project home: http://compcache.googlecode.com

 */



#ifndef _ZRAM_IOCTL_H_

#define _ZRAM_IOCTL_H_



struct zram_ioctl_stats {

	u64 disksize;		/* disksize in bytes (user specifies in KB) */

	u64 num_reads;		/* failed + successful */

	u64 num_writes;		/* --do-- */

	u64 failed_reads;	/* should NEVER! happen */

	u64 failed_writes;	/* can happen when memory is too low */

	u64 invalid_io;		/* non-page-aligned I/O requests */

	u64 notify_free;	/* no. of swap slot free notifications */

	u32 pages_zero;		/* no. of zero filled pages */

	u32 good_compress_pct;	/* no. of pages with compression ratio<=50% */

	u32 pages_expand_pct;	/* no. of incompressible pages */

	u32 pages_stored;

	u32 pages_used;

	u64 orig_data_size;

	u64 compr_data_size;

	u64 mem_used_total;

} __attribute__ ((packed, aligned(4)));



#define ZRAMIO_SET_DISKSIZE_KB	_IOW('z', 0, size_t)

#define ZRAMIO_GET_STATS	_IOR('z', 1, struct zram_ioctl_stats)

#define ZRAMIO_INIT		_IO('z', 2)

#define ZRAMIO_RESET		_IO('z', 3)



#endif

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