diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 8 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 24 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.c | 32 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.h | 2 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 37 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 1 |
6 files changed, 93 insertions, 11 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index 0da9ed6..70ec992 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -65,6 +65,14 @@ Description: number of backend's zcomp_strm compression streams (number of concurrent compress operations). +What: /sys/block/zram<id>/comp_algorithm +Date: February 2014 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The comp_algorithm file is read-write and lets to show + available and selected compression algorithms, change + compression algorithm selection. + What: /sys/block/zram<id>/notify_free Date: August 2010 Contact: Nitin Gupta <ngupta@vflare.org> diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index aadfe60..2604ffe 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -42,7 +42,21 @@ will not take any effect, because single stream compression backend implemented as a special case and does not support dynamic max_comp_streams. Only multi stream backend supports dynamic max_comp_streams adjustment. -3) Set Disksize +3) Select compression algorithm + Using comp_algorithm device attribute one can see available and + currently selected (shown in square brackets) compression algortithms, + change selected compression algorithm (once the device is initialised + there is no way to change compression algorithm). + + Examples: + #show supported compression algorithms + cat /sys/block/zram0/comp_algorithm + lzo [lz4] + + #select lzo compression algorithm + echo lzo > /sys/block/zram0/comp_algorithm + +4) Set Disksize Set disk size by writing the value to sysfs node 'disksize'. The value can be either in bytes or you can use mem suffixes. Examples: @@ -59,14 +73,14 @@ There is little point creating a zram of greater than twice the size of memory since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the size of the disk when not in use so a huge zram is wasteful. -4) Activate: +5) Activate: mkswap /dev/zram0 swapon /dev/zram0 mkfs.ext4 /dev/zram1 mount /dev/zram1 /tmp -5) Stats: +6) Stats: Per-device statistics are exported as various nodes under /sys/block/zram<id>/ disksize @@ -81,11 +95,11 @@ size of the disk when not in use so a huge zram is wasteful. compr_data_size mem_used_total -6) Deactivate: +7) Deactivate: swapoff /dev/zram0 umount /dev/zram1 -7) Reset: +8) Reset: Write any positive value to 'reset' sysfs node echo 1 > /sys/block/zram0/reset echo 1 > /sys/block/zram1/reset diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index ac276f7..aad533a 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -39,11 +39,20 @@ struct zcomp_strm_multi { wait_queue_head_t strm_wait; }; +static struct zcomp_backend *backends[] = { + &zcomp_lzo, + NULL +}; + static struct zcomp_backend *find_backend(const char *compress) { - if (strncmp(compress, "lzo", 3) == 0) - return &zcomp_lzo; - return NULL; + int i = 0; + while (backends[i]) { + if (sysfs_streq(compress, backends[i]->name)) + break; + i++; + } + return backends[i]; } static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) @@ -251,6 +260,23 @@ static int zcomp_strm_single_create(struct zcomp *comp) return 0; } +/* show available compressors */ +ssize_t zcomp_available_show(const char *comp, char *buf) +{ + ssize_t sz = 0; + int i = 0; + + while (backends[i]) { + if (sysfs_streq(comp, backends[i]->name)) + sz += sprintf(buf + sz, "[%s] ", backends[i]->name); + else + sz += sprintf(buf + sz, "%s ", backends[i]->name); + i++; + } + sz += sprintf(buf + sz, "\n"); + return sz; +} + int zcomp_set_max_streams(struct zcomp *comp, int num_strm) { return comp->set_max_streams(comp, num_strm); diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index bd11d59..8b8997f 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -50,6 +50,8 @@ struct zcomp { void (*destroy)(struct zcomp *comp); }; +ssize_t zcomp_available_show(const char *comp, char *buf); + struct zcomp *zcomp_create(const char *comp, int max_strm); void zcomp_destroy(struct zcomp *comp); diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 3a5f24c..15d46f2 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -141,6 +141,34 @@ static ssize_t max_comp_streams_store(struct device *dev, return len; } +static ssize_t comp_algorithm_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + size_t sz; + struct zram *zram = dev_to_zram(dev); + + down_read(&zram->init_lock); + sz = zcomp_available_show(zram->compressor, buf); + up_read(&zram->init_lock); + + return sz; +} + +static ssize_t comp_algorithm_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + struct zram *zram = dev_to_zram(dev); + down_write(&zram->init_lock); + if (init_done(zram)) { + up_write(&zram->init_lock); + pr_info("Can't change algorithm for initialized device\n"); + return -EBUSY; + } + strlcpy(zram->compressor, buf, sizeof(zram->compressor)); + up_write(&zram->init_lock); + return len; +} + /* flag operations needs meta->tb_lock */ static int zram_test_flag(struct zram_meta *meta, u32 index, enum zram_pageflags flag) @@ -572,10 +600,10 @@ static ssize_t disksize_store(struct device *dev, goto out_free_meta; } - zram->comp = zcomp_create(default_compressor, zram->max_comp_streams); + zram->comp = zcomp_create(zram->compressor, zram->max_comp_streams); if (!zram->comp) { pr_info("Cannot initialise %s compressing backend\n", - default_compressor); + zram->compressor); err = -EINVAL; goto out_free_meta; } @@ -735,6 +763,8 @@ static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); static DEVICE_ATTR(max_comp_streams, S_IRUGO | S_IWUSR, max_comp_streams_show, max_comp_streams_store); +static DEVICE_ATTR(comp_algorithm, S_IRUGO | S_IWUSR, + comp_algorithm_show, comp_algorithm_store); ZRAM_ATTR_RO(num_reads); ZRAM_ATTR_RO(num_writes); @@ -760,6 +790,7 @@ static struct attribute *zram_disk_attrs[] = { &dev_attr_compr_data_size.attr, &dev_attr_mem_used_total.attr, &dev_attr_max_comp_streams.attr, + &dev_attr_comp_algorithm.attr, NULL, }; @@ -820,7 +851,7 @@ static int create_device(struct zram *zram, int device_id) pr_warn("Error creating sysfs group"); goto out_free_disk; } - + strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); zram->meta = NULL; zram->max_comp_streams = 1; return 0; diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index ccf36d1..7f21c14 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -101,5 +101,6 @@ struct zram { u64 disksize; /* bytes */ int max_comp_streams; struct zram_stats stats; + char compressor[10]; }; #endif |
