diff options
| -rw-r--r-- | Documentation/ABI/obsolete/sysfs-block-zram | 119 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 16 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 15 |
3 files changed, 150 insertions, 0 deletions
diff --git a/Documentation/ABI/obsolete/sysfs-block-zram b/Documentation/ABI/obsolete/sysfs-block-zram new file mode 100644 index 000000000000..720ea92cfb2e --- /dev/null +++ b/Documentation/ABI/obsolete/sysfs-block-zram @@ -0,0 +1,119 @@ +What: /sys/block/zram<id>/num_reads +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The num_reads file is read-only and specifies the number of + reads (failed or successful) done on this device. + Now accessible via zram<id>/stat node. + +What: /sys/block/zram<id>/num_writes +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The num_writes file is read-only and specifies the number of + writes (failed or successful) done on this device. + Now accessible via zram<id>/stat node. + +What: /sys/block/zram<id>/invalid_io +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The invalid_io file is read-only and specifies the number of + non-page-size-aligned I/O requests issued to this device. + Now accessible via zram<id>/io_stat node. + +What: /sys/block/zram<id>/failed_reads +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The failed_reads file is read-only and specifies the number of + failed reads happened on this device. + Now accessible via zram<id>/io_stat node. + +What: /sys/block/zram<id>/failed_writes +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The failed_writes file is read-only and specifies the number of + failed writes happened on this device. + Now accessible via zram<id>/io_stat node. + +What: /sys/block/zram<id>/notify_free +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The notify_free file is read-only. Depending on device usage + scenario it may account a) the number of pages freed because + of swap slot free notifications or b) the number of pages freed + because of REQ_DISCARD requests sent by bio. The former ones + are sent to a swap block device when a swap slot is freed, which + implies that this disk is being used as a swap disk. The latter + ones are sent by filesystem mounted with discard option, + whenever some data blocks are getting discarded. + Now accessible via zram<id>/io_stat node. + +What: /sys/block/zram<id>/zero_pages +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The zero_pages file is read-only and specifies number of zero + filled pages written to this disk. No memory is allocated for + such pages. + Now accessible via zram<id>/mm_stat node. + +What: /sys/block/zram<id>/orig_data_size +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The orig_data_size file is read-only and specifies uncompressed + size of data stored in this disk. This excludes zero-filled + pages (zero_pages) since no memory is allocated for them. + Unit: bytes + Now accessible via zram<id>/mm_stat node. + +What: /sys/block/zram<id>/compr_data_size +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The compr_data_size file is read-only and specifies compressed + size of data stored in this disk. So, compression ratio can be + calculated using orig_data_size and this statistic. + Unit: bytes + Now accessible via zram<id>/mm_stat node. + +What: /sys/block/zram<id>/mem_used_total +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The mem_used_total file is read-only and specifies the amount + of memory, including allocator fragmentation and metadata + overhead, allocated for this disk. So, allocator space + efficiency can be calculated using compr_data_size and this + statistic. + Unit: bytes + Now accessible via zram<id>/mm_stat node. + +What: /sys/block/zram<id>/mem_used_max +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The mem_used_max file is read/write and specifies the amount + of maximum memory zram have consumed to store compressed data. + For resetting the value, you should write "0". Otherwise, + you could see -EINVAL. + Unit: bytes + Downgraded to write-only node: so it's possible to set new + value only; its current value is stored in zram<id>/mm_stat + node. + +What: /sys/block/zram<id>/mem_limit +Date: August 2015 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The mem_limit file is read/write and specifies the maximum + amount of memory ZRAM can use to store the compressed data. + The limit could be changed in run time and "0" means disable + the limit. No limit is the initial state. Unit: bytes + Downgraded to write-only node: so it's possible to set new + value only; its current value is stored in zram<id>/mm_stat + node. diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 7920f4026d36..48a183e29988 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -128,6 +128,22 @@ mem_limit RW the maximum amount of memory ZRAM can use to store num_migrated RO the number of objects migrated migrated by compaction +WARNING +======= +per-stat sysfs attributes are considered to be deprecated. +The basic strategy is: +-- the existing RW nodes will be downgraded to WO nodes (in linux 4.11) +-- deprecated RO sysfs nodes will eventually be removed (in linux 4.11) + +The list of deprecated attributes can be found here: +Documentation/ABI/obsolete/sysfs-block-zram + +Basically, every attribute that has its own read accessible sysfs node +(e.g. num_reads) *AND* is accessible via one of the stat files (zram<id>/stat +or zram<id>/io_stat or zram<id>/mm_stat) is considered to be deprecated. + +User space is advised to use the following files to read the device statistics. + File /sys/block/zram<id>/stat Represents block layer statistics. Read Documentation/block/stat.txt for diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index c94a1a98e301..4491787095a0 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -43,11 +43,22 @@ static const char *default_compressor = "lzo"; /* Module params (documentation at end) */ static unsigned int num_devices = 1; +static inline void deprecated_attr_warn(const char *name) +{ + pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n", + task_pid_nr(current), + current->comm, + name, + "See zram documentation."); +} + #define ZRAM_ATTR_RO(name) \ static ssize_t name##_show(struct device *d, \ struct device_attribute *attr, char *b) \ { \ struct zram *zram = dev_to_zram(d); \ + \ + deprecated_attr_warn(__stringify(name)); \ return scnprintf(b, PAGE_SIZE, "%llu\n", \ (u64)atomic64_read(&zram->stats.name)); \ } \ @@ -89,6 +100,7 @@ static ssize_t orig_data_size_show(struct device *dev, { struct zram *zram = dev_to_zram(dev); + deprecated_attr_warn("orig_data_size"); return scnprintf(buf, PAGE_SIZE, "%llu\n", (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT); } @@ -99,6 +111,7 @@ static ssize_t mem_used_total_show(struct device *dev, u64 val = 0; struct zram *zram = dev_to_zram(dev); + deprecated_attr_warn("mem_used_total"); down_read(&zram->init_lock); if (init_done(zram)) { struct zram_meta *meta = zram->meta; @@ -128,6 +141,7 @@ static ssize_t mem_limit_show(struct device *dev, u64 val; struct zram *zram = dev_to_zram(dev); + deprecated_attr_warn("mem_limit"); down_read(&zram->init_lock); val = zram->limit_pages; up_read(&zram->init_lock); @@ -159,6 +173,7 @@ static ssize_t mem_used_max_show(struct device *dev, u64 val = 0; struct zram *zram = dev_to_zram(dev); + deprecated_attr_warn("mem_used_max"); down_read(&zram->init_lock); if (init_done(zram)) val = atomic_long_read(&zram->stats.max_used_pages); |