On (09/24/15 18:50), Sergey Senozhatsky wrote:
[..]
> +There are several ways to configure and manage zram device(-s):
> +a) using zram and zram_control sysfs attributes
> +b) using zramctl utility, provided by util-linux
> ([email protected]).
> +
> +In this document we will describe only 'manual' zram configuration steps,
> +IOW, zram and zram_control sysfs attributes.
> +
> +In order to get a better idea about zramctl please consult util-linux
> +documentation, zramctl man-page or `zramctl --help'. Please be informed
> +that zram maintainers do not develop/maintain util-linux or zramctl, should
> +you have a questions please contact [email protected]
^^^
d'oh! should have been "any"
I'll resend shortly. Sorry.
-ss
> Following shows a typical sequence of steps for using zram.
>
> +WARNING
> +=======
> +For the sake of simplicity we skip error checking parts in most of the
> +examples below. However, it is your sole responsibility to handle errors.
> +
> +zram sysfs attributes always return negative values in case of errors.
> +The list of possible return codes:
> +-EBUSY -- an attempt to modify an attribute that cannot be changed once
> +the device has been initialised. Please reset device first;
> +-ENOMEM -- zram was not able to allocate enough memory to fulfil your
> +needs;
> +-EINVAL -- invalid input has been provided.
> +
> +If you use 'echo', the returned value that is changed by 'echo' utility,
> +and, in general case, something like:
> +
> + echo 3 > /sys/block/zram0/max_comp_streams
> + if [ $? -ne 0 ];
> + handle_error
> + fi
> +
> +should suffice.
> +
> 1) Load Module:
> modprobe zram num_devices=4
> This creates 4 devices: /dev/zram{0,1,2,3}
> @@ -47,7 +82,7 @@ max_comp_streams adjustment.
>
> 3) Select compression algorithm
> Using comp_algorithm device attribute one can see available and
> - currently selected (shown in square brackets) compression algortithms,
> + currently selected (shown in square brackets) compression algorithms,
> change selected compression algorithm (once the device is initialised
> there is no way to change compression algorithm).
>
> @@ -119,7 +154,7 @@ execute
> 8) Stats:
> Per-device statistics are exported as various nodes under
> /sys/block/zram<id>/
>
> -A brief description of exported device attritbutes. For more details please
> +A brief description of exported device attributes. For more details please
> read Documentation/ABI/testing/sysfs-block-zram.
>
> Name access description
> @@ -140,8 +175,9 @@ 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 memory zram have consumed to
> - store compressed data
> +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
> --
> 2.5.3
>
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