Messages in this thread | | | Date | Thu, 24 Sep 2015 18:55:04 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH] zram: update documentation |
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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 (util-linux@vger.kernel.org). > + > +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 util-linux@vger.kernel.org ^^^ 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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