diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/obsolete/sysfs-block-zram | 119 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 101 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 74 |
3 files changed, 40 insertions, 254 deletions
diff --git a/Documentation/ABI/obsolete/sysfs-block-zram b/Documentation/ABI/obsolete/sysfs-block-zram deleted file mode 100644 index 720ea92cfb2e..000000000000 --- a/Documentation/ABI/obsolete/sysfs-block-zram +++ /dev/null @@ -1,119 +0,0 @@ -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/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index 4518d30b8c2e..451b6d882b2c 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -22,41 +22,6 @@ Description: device. The reset operation frees all the memory associated with this device. -What: /sys/block/zram<id>/num_reads -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -Description: - The num_reads file is read-only and specifies the number of - reads (failed or successful) done on this device. - -What: /sys/block/zram<id>/num_writes -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -Description: - The num_writes file is read-only and specifies the number of - writes (failed or successful) done on this device. - -What: /sys/block/zram<id>/invalid_io -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -Description: - The invalid_io file is read-only and specifies the number of - non-page-size-aligned I/O requests issued to this device. - -What: /sys/block/zram<id>/failed_reads -Date: February 2014 -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. - -What: /sys/block/zram<id>/failed_writes -Date: February 2014 -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. - What: /sys/block/zram<id>/max_comp_streams Date: February 2014 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> @@ -73,74 +38,24 @@ Description: 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> -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. - -What: /sys/block/zram<id>/zero_pages -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -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. - -What: /sys/block/zram<id>/orig_data_size -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -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 - -What: /sys/block/zram<id>/compr_data_size -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -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 - -What: /sys/block/zram<id>/mem_used_total -Date: August 2010 -Contact: Nitin Gupta <ngupta@vflare.org> -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 - What: /sys/block/zram<id>/mem_used_max Date: August 2014 Contact: Minchan Kim <minchan@kernel.org> 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. + The mem_used_max file is write-only and is used to reset + the counter 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 What: /sys/block/zram<id>/mem_limit Date: August 2014 Contact: Minchan Kim <minchan@kernel.org> 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 + The mem_limit file is write-only 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 What: /sys/block/zram<id>/compact Date: August 2015 diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 0535ae1f73e5..1c0c08d9206b 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -161,42 +161,14 @@ Name access description disksize RW show and set the device's disk size initstate RO shows the initialization state of the device reset WO trigger device reset -num_reads RO the number of reads -failed_reads RO the number of failed reads -num_write RO the number of writes -failed_writes RO the number of failed writes -invalid_io RO the number of non-page-size-aligned I/O requests +mem_used_max WO reset the `mem_used_max' counter (see later) +mem_limit WO specifies the maximum amount of memory ZRAM can use + to store the compressed data max_comp_streams RW the number of possible concurrent compress operations comp_algorithm RW show and change the compression algorithm -notify_free RO the number of notifications to free pages (either - slot free notifications or REQ_DISCARD requests) -zero_pages RO the number of zero filled pages written to this disk -orig_data_size RO uncompressed size of data stored in this disk -compr_data_size RO compressed size of data stored in this disk -mem_used_total RO the amount of memory allocated for this disk -mem_used_max RW the maximum amount of memory zram have consumed to - store the data (to reset this counter to the actual - current value, write 1 to this attribute) -mem_limit RW the maximum amount of memory ZRAM can use to store - the compressed data -pages_compacted RO the number of pages freed during compaction - (available only via zram<id>/mm_stat node) compact WO trigger memory compaction debug_stat RO this file is used for zram debugging purposes -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. @@ -211,22 +183,40 @@ The stat file represents device's I/O statistics not accounted by block layer and, thus, not available in zram<id>/stat file. It consists of a single line of text and contains the following stats separated by whitespace: - failed_reads - failed_writes - invalid_io - notify_free + failed_reads the number of failed reads + failed_writes the number of failed writes + invalid_io the number of non-page-size-aligned I/O requests + notify_free 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. File /sys/block/zram<id>/mm_stat The stat file represents device's mm statistics. It consists of a single line of text and contains the following stats separated by whitespace: - orig_data_size - compr_data_size - mem_used_total - mem_limit - mem_used_max - zero_pages - num_migrated + orig_data_size uncompressed size of data stored in this disk. + This excludes zero-filled pages (zero_pages) since no + memory is allocated for them. + Unit: bytes + compr_data_size compressed size of data stored in this disk + mem_used_total the amount of memory allocated for this disk. This + includes 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 + mem_limit the maximum amount of memory ZRAM can use to store + the compressed data + mem_used_max the maximum amount of memory zram have consumed to + store the data + zero_pages the number of zero filled pages written to this disk. + No memory is allocated for such pages. + pages_compacted the number of pages freed during compaction 9) Deactivate: swapoff /dev/zram0 |