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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: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
Nitin Gupta 2010-08-09 22:56:47 +05:30 committed by Greg Kroah-Hartman
parent e1a164d7a3
commit 33863c21e6
6 changed files with 305 additions and 231 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/staging/zram/Kconfig
View File

@ -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.

2
drivers/staging/zram/Makefile
View File

@ -1,3 +1,3 @@
zram-objs := zram_drv.o xvmalloc.o
zram-objs := zram_drv.o zram_sysfs.o xvmalloc.o
obj-$(CONFIG_ZRAM) += zram.o

186
drivers/staging/zram/zram_drv.c
View File

@ -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");

53
drivers/staging/zram/zram_drv.h
View File

@ -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;
};
/*-- */
extern struct zram *devices;
extern unsigned int num_devices;
#ifdef CONFIG_SYSFS
extern struct attribute_group zram_disk_attr_group;
#endif
/* 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 int zram_init_device(struct zram *zram);
extern void zram_reset_device(struct zram *zram);
#endif

41
drivers/staging/zram/zram_ioctl.h
View File

@ -1,41 +0,0 @@
/*
* 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

242
drivers/staging/zram/zram_sysfs.c 100644
View File

@ -0,0 +1,242 @@
/*
* 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/
*/
#include <linux/device.h>
#include <linux/genhd.h>
#include "zram_drv.h"
#ifdef CONFIG_SYSFS
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;
}
static struct zram *dev_to_zram(struct device *dev)
{
int i;
struct zram *zram = NULL;
for (i = 0; i < num_devices; i++) {
zram = &devices[i];
if (disk_to_dev(zram->disk) == dev)
break;
}
return zram;
}
static ssize_t disksize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n", zram->disksize);
}
static ssize_t disksize_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
struct zram *zram = dev_to_zram(dev);
if (zram->init_done)
return -EBUSY;
ret = strict_strtoull(buf, 10, &zram->disksize);
if (ret)
return ret;
zram->disksize &= PAGE_MASK;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
return len;
}
static ssize_t initstate_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%u\n", zram->init_done);
}
static ssize_t initstate_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
unsigned long do_init;
struct zram *zram = dev_to_zram(dev);
ret = strict_strtoul(buf, 10, &do_init);
if (ret)
return ret;
if (!do_init)
return -EINVAL;
zram_init_device(zram);
return len;
}
static ssize_t reset_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
unsigned long do_reset;
struct zram *zram;
struct block_device *bdev;
zram = dev_to_zram(dev);
bdev = bdget_disk(zram->disk, 0);
/* Do not reset an active device! */
if (bdev->bd_holders)
return -EBUSY;
ret = strict_strtoul(buf, 10, &do_reset);
if (ret)
return ret;
if (!do_reset)
return -EINVAL;
/* Make sure all pending I/O is finished */
if (bdev)
fsync_bdev(bdev);
if (zram->init_done)
zram_reset_device(zram);
return len;
}
static ssize_t num_reads_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
zram_stat64_read(zram, &zram->stats.num_reads));
}
static ssize_t num_writes_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
zram_stat64_read(zram, &zram->stats.num_writes));
}
static ssize_t invalid_io_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
zram_stat64_read(zram, &zram->stats.invalid_io));
}
static ssize_t notify_free_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
zram_stat64_read(zram, &zram->stats.notify_free));
}
static ssize_t zero_pages_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%u\n", zram->stats.pages_zero);
}
static ssize_t orig_data_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
(u64)(zram->stats.pages_stored) << PAGE_SHIFT);
}
static ssize_t compr_data_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return sprintf(buf, "%llu\n",
zram_stat64_read(zram, &zram->stats.compr_size));
}
static ssize_t mem_used_total_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
u64 val = 0;
struct zram *zram = dev_to_zram(dev);
if (zram->init_done) {
val = xv_get_total_size_bytes(zram->mem_pool) +
((u64)(zram->stats.pages_expand) << PAGE_SHIFT);
}
return sprintf(buf, "%llu\n", val);
}
static DEVICE_ATTR(disksize, S_IRUGO | S_IWUGO,
disksize_show, disksize_store);
static DEVICE_ATTR(initstate, S_IRUGO | S_IWUGO,
initstate_show, initstate_store);
static DEVICE_ATTR(reset, S_IWUGO, NULL, reset_store);
static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL);
static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL);
static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL);
static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL);
static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL);
static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL);
static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL);
static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL);
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
&dev_attr_initstate.attr,
&dev_attr_reset.attr,
&dev_attr_num_reads.attr,
&dev_attr_num_writes.attr,
&dev_attr_invalid_io.attr,
&dev_attr_notify_free.attr,
&dev_attr_zero_pages.attr,
&dev_attr_orig_data_size.attr,
&dev_attr_compr_data_size.attr,
&dev_attr_mem_used_total.attr,
NULL,
};
struct attribute_group zram_disk_attr_group = {
.attrs = zram_disk_attrs,
};
#endif /* CONFIG_SYSFS */