08 Sep, 2017
1 commit
-
Pull SCSI updates from James Bottomley:
"This is mostly updates of the usual suspects: lpfc, qla2xxx, hisi_sas,
megaraid_sas, zfcp and a host of minor updates.The major driver change here is the elimination of the block based
cciss driver in favour of the SCSI based hpsa driver (which now drives
all the legacy cases cciss used to be required for). Plus a reset
handler clean up and the redo of the SAS SMP handler to use bsg lib"* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (279 commits)
scsi: scsi-mq: Always unprepare before requeuing a request
scsi: Show .retries and .jiffies_at_alloc in debugfs
scsi: Improve requeuing behavior
scsi: Call scsi_initialize_rq() for filesystem requests
scsi: qla2xxx: Reset the logo flag, after target re-login.
scsi: qla2xxx: Fix slow mem alloc behind lock
scsi: qla2xxx: Clear fc4f_nvme flag
scsi: qla2xxx: add missing includes for qla_isr
scsi: qla2xxx: Fix an integer overflow in sysfs code
scsi: aacraid: report -ENOMEM to upper layer from aac_convert_sgraw2()
scsi: aacraid: get rid of one level of indentation
scsi: aacraid: fix indentation errors
scsi: storvsc: fix memory leak on ring buffer busy
scsi: scsi_transport_sas: switch to bsg-lib for SMP passthrough
scsi: smartpqi: remove the smp_handler stub
scsi: hpsa: remove the smp_handler stub
scsi: bsg-lib: pass the release callback through bsg_setup_queue
scsi: Rework handling of scsi_device.vpd_pg8[03]
scsi: Rework the code for caching Vital Product Data (VPD)
scsi: rcu: Introduce rcu_swap_protected()
...
07 Sep, 2017
1 commit
-
This patch adds document and kconfig for using of writeback feature.
Link: http://lkml.kernel.org/r/1498459987-24562-10-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim
Cc: Juneho Choi
Cc: Sergey Senozhatsky
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Aug, 2017
1 commit
-
The hpsa driver now has support for all boards the cciss driver
used to support, so this patch removes the cciss driver and
make hpsa an alias to cciss.Signed-off-by: Hannes Reinecke
Acked-by: Don Brace
Signed-off-by: Martin K. Petersen
15 Apr, 2017
1 commit
-
This drivers was added in 2008, but as far as a I can tell we never had a
single platform that actually registered resources for the platform driver.It's also been unmaintained for a long time and apparently has a ATA mode
that can be driven using the IDE/libata subsystem.Signed-off-by: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe
28 Feb, 2017
1 commit
-
Fix typos and add the following to the scripts/spelling.txt:
followings||following
While we are here, add a missing colon in the boilerplate in DT binding
documents. The "you SoC" in allwinner,sunxi-pinctrl.txt was fixed as
well.I reworded "as the followings:" to "as follows:" for
drivers/usb/gadget/udc/renesas_usb3.c.Link: http://lkml.kernel.org/r/1481573103-11329-32-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Feb, 2017
1 commit
-
The idea is that without doing more calculations we extend zero pages to
same element pages for zram. zero page is special case of same element
page with zero element.1. the test is done under android 7.0
2. startup too many applications circularly
3. sample the zero pages, same pages (none-zero element)
and total pages in function page_zero_filledthe result is listed as below:
ZERO SAME TOTAL
36214 17842 598196ZERO/TOTAL SAME/TOTAL (ZERO+SAME)/TOTAL ZERO/SAME
AVERAGE 0.060631909 0.024990816 0.085622726 2.663825038
STDEV 0.00674612 0.005887625 0.009707034 2.115881328
MAX 0.069698422 0.030046087 0.094975336 7.56043956
MIN 0.03959586 0.007332205 0.056055193 1.928985507from the above data, the benefit is about 2.5% and up to 3% of total
swapout pages.The defect of the patch is that when we recovery a page from non-zero
element the operations are low efficient for partial read.This patch extends zero_page to same_page so if there is any user to
have monitored zero_pages, he will be surprised if the number is
increased but it's not harmful, I believe.[minchan@kernel.org: do not free same element pages in zram_meta_free]
Link: http://lkml.kernel.org/r/20170207065741.GA2567@bbox
Link: http://lkml.kernel.org/r/1483692145-75357-1-git-send-email-zhouxianrong@huawei.com
Link: http://lkml.kernel.org/r/1486307804-27903-1-git-send-email-minchan@kernel.org
Signed-off-by: zhouxianrong
Signed-off-by: Minchan Kim
Cc: Sergey Senozhatsky
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Feb, 2017
1 commit
-
We had a deprecated_attr_warn() warning for 2 years and now the time has
come and we finally can do the cleanup.The plan was as follows:
: 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/stat or zram/io_stat or zram/mm_stat) is considered
: to be deprecated.The patch also removes `obsolete/sysfs-block-zram', clean ups
`testing/sysfs-block-zram' and tweaks zram.txt files.Link: http://lkml.kernel.org/r/20170118035838.11090-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Jonathan Corbet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Oct, 2016
1 commit
-
The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.Signed-off-by: Mauro Carvalho Chehab
22 Oct, 2016
1 commit
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This patch fix a spelling typo in cciss.txt
Signed-off-by: Masanari Iida
Acked-by: Don Brace
Signed-off-by: Jonathan Corbet
27 Jul, 2016
2 commits
-
zram documentation is a mix of different styles: spaces, tabs, tabs +
spaces, etc. Clean it up.Link: http://lkml.kernel.org/r/20160531122017.2878-6-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Joonsoo Kim
Cc: Jonathan Corbet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There is no way to get a string with all the crypto comp algorithms
supported by the crypto comp engine, so we need to maintain our own
backends list. At the same time we additionally need to use
crypto_has_comp() to make sure that the user has requested a compression
algorithm that is recognized by the crypto comp engine. Relying on
/proc/crypto is not an options here, because it does not show
not-yet-inserted compression modules.Example:
modprobe zram
cat /proc/crypto | grep -i lz4
modprobe lz4
cat /proc/crypto | grep -i lz4
name : lz4
driver : lz4-generic
module : lz4So the user can't tell exactly if the lz4 is really supported from
/proc/crypto output, unless someone or something has loaded it.This patch also adds crypto_has_comp() to zcomp_available_show(). We
store all the compression algorithms names in zcomp's `backends' array,
regardless the CONFIG_CRYPTO_FOO configuration, but show only those that
are also supported by crypto engine. This helps user to know the exact
list of compression algorithms that can be used.Example:
module lz4 is not loaded yet, but is supported by the crypto
engine. /proc/crypto has no information on this module, while
zram's `comp_algorithm' lists it:cat /proc/crypto | grep -i lz4
cat /sys/block/zram0/comp_algorithm
[lzo] lz4 deflate lz4hc 842We still use the `backends' array to determine if the requested
compression backend is known to crypto api. This array, however, may not
contain some entries, therefore as the last step we call crypto_has_comp()
function which attempts to insmod the requested compression algorithm to
determine if crypto api supports it. The advantage of this method is that
now we permit the usage of out-of-tree crypto compression modules
(implementing S/W or H/W compression).[sergey.senozhatsky@gmail.com: zram-use-crypto-api-to-check-alg-availability-v3]
Link: http://lkml.kernel.org/r/20160604024902.11778-4-sergey.senozhatsky@gmail.com
Link: http://lkml.kernel.org/r/20160531122017.2878-5-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Joonsoo Kim
Signed-off-by: Sergey Senozhatsky
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 May, 2016
2 commits
-
debug_stat sysfs is read-only and represents various debugging data that
zram developers may need. This file is not meant to be used by anyone
else: its content is not documented and will change any time w/o any
notice. Therefore, the output of debug_stat file contains a version
string. To avoid any confusion, we will increase the version number
every time we modify the output.At the moment this file exports only one value -- the number of
re-compressions, IOW, the number of times compression fast path has
failed. This stat is temporary any will be useful in case if any
per-cpu compression streams regressions will be reported.Link: http://lkml.kernel.org/r/20160513230834.GB26763@bbox
Link: http://lkml.kernel.org/r/20160511134553.12655-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky
Signed-off-by: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove the internal part of max_comp_streams interface, since we
switched to per-cpu streams. We will keep RW max_comp_streams attr
around, because:a) we may (silently) switch back to idle compression streams list and
don't want to disturb user spaceb) max_comp_streams attr must wait for the next 'lay off cycle'; we
give user space 2 years to adjust before we remove/downgrade the attr,
and there are already several attrs scheduled for removal in 4.11, so
it's too late for max_comp_streams.This slightly change a user visible behaviour:
- First, reading from max_comp_stream file now will always return the
number of online CPUs.- Second, writing to max_comp_stream will not take any effect.
Link: http://lkml.kernel.org/r/20160503165546.25201-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky
Cc: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Mar, 2016
1 commit
-
We disabled the ability to enable this driver back in October of 2013,
we should be able to safely remove it at this point. The initial goal
was to remove it in 3.15, so now is the time.Signed-off-by: Jens Axboe
25 Sep, 2015
1 commit
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Several documentation changes.
First, we never mentioned any errors and never required any
error checks in documentation.Second, mention that there is another way to configure and
manage zram devices -- zramctl, provided by util-linux.Third, add a bit of clarification on why `mem_used_max' attr
is RW and correct some typos.Signed-off-by: Sergey Senozhatsky
Signed-off-by: Jonathan Corbet
09 Sep, 2015
1 commit
-
Compaction returns back to zram the number of migrated objects, which is
quite uninformative -- we have objects of different sizes so user space
cannot obtain any valuable data from that number. Change compaction to
operate in terms of pages and return back to compaction issuer the
number of pages that were freed during compaction. So from now on we
will export more meaningful value in zram/mm_stat -- the number of
freed (compacted) pages.This requires:
(a) a rename of `num_migrated' to 'pages_compacted'
(b) a internal API change -- return first_page's fullness_group from
putback_zspage(), so we know when putback_zspage() did
free_zspage(). It helps us to account compaction stats correctly.Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Jun, 2015
3 commits
-
We currently don't support on-demand device creation. The one and only
way to have N zram devices is to specify num_devices module parameter
(default value: 1). IOW if, for some reason, at some point, user wants
to have N + 1 devies he/she must umount all the existing devices, unload
the module, load the module passing num_devices equals to N + 1. And do
this again, if needed.This patch introduces zram control sysfs class, which has two sysfs
attrs:
- hot_add -- add a new zram device
- hot_remove -- remove a specific (device_id) zram devicehot_add sysfs attr is read-only and has only automatic device id
assignment mode (as requested by Minchan Kim). read operation performed
on this attr creates a new zram device and returns back its device_id or
error status.Usage example:
# add a new specific zram device
cat /sys/class/zram-control/hot_add
2# remove a specific zram device
echo 4 > /sys/class/zram-control/hot_removeReturning zram_add() error code back to user (-ENOMEM in this case)
cat /sys/class/zram-control/hot_add
cat: /sys/class/zram-control/hot_add: Cannot allocate memoryNOTE, there might be users who already depend on the fact that at least
zram0 device gets always created by zram_init(). Preserve this behavior.[minchan@kernel.org: use zram->claim to avoid lockdep splat]
Signed-off-by: Sergey Senozhatsky
Cc: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Limiting the number of zram devices to 32 (default max_num_devices value)
is confusing, let's drop it. A user with 2TB or 4TB of RAM, for example,
can request as many devices as he can handle.Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We currently don't support zram on-demand device creation. The only way
to have N zram devices is to specify num_devices module parameter (default
value 1). That means that if, for some reason, at some point, user wants
to have N + 1 devies he/she must umount all the existing devices, unload
the module, load the module passing num_devices equals to N + 1.This patchset introduces zram-control sysfs class, which has two sysfs
attrs:- hot_add -- add a new zram device
- hot_remove -- remove a specific (device_id) zram deviceUsage example:
# add a new specific zram device
cat /sys/class/zram-control/hot_add
1# remove a specific zram device
echo 4 > /sys/class/zram-control/hot_removeThis patch (of 10):
Briefly describe missing `compact` sysfs entry.
Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Apr, 2015
1 commit
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Pull block driver updates from Jens Axboe:
"This is the block driver pull request for 4.1. As with the core bits,
this is a relatively slow round. This pull request contains:- Various fixes and cleanups for NVMe, from Alexey Khoroshilov, Chong
Yuan, myself, Keith Busch, and Murali Iyer.- Documentation and code cleanups for nbd from Markus Pargmann.
- Change of brd maintainer to me, from Ross Zwisler. At least the
email doesn't bounce anymore then.- Two xen-blkback fixes from Tao Chen"
* 'for-4.1/drivers' of git://git.kernel.dk/linux-block: (23 commits)
NVMe: Meta data handling through submit io ioctl
NVMe: Add translation for block limits
NVMe: Remove check for null
NVMe: Fix error handling of class_create("nvme")
xen-blkback: define pr_fmt macro to avoid the duplication of DRV_PFX
xen-blkback: enlarge the array size of blkback name
nbd: Return error pointer directly
nbd: Return error code directly
nbd: Remove fixme that was already fixed
nbd: Restructure debugging prints
nbd: Fix device bytesize type
nbd: Replace kthread_create with kthread_run
nbd: Remove kernel internal header
Documentation: nbd: Add list of module parameters
Documentation: nbd: Reformat to allow more documentation
NVMe: increase depth of admin queue
nvme: Fix PRP list calculation for non-4k system page size
NVMe: Fix blk-mq hot cpu notification
NVMe: embedded iod mask cleanup
NVMe: Freeze admin queue on device failure
...
16 Apr, 2015
4 commits
-
Add Documentation/ABI/obsolete/sysfs-block-zram file and list obsolete and
deprecated attributes there. The patch also adds additional information
to zram documentation and describes the basic strategy:- the existing RW nodes will be downgraded to WO nodes (in 4.11)
- deprecated RO sysfs nodes will eventually be removed (in 4.11)Users will be additionally notified about deprecated attr usage by
pr_warn_once() (added to every deprecated attr _show()), as suggested by
Minchan Kim.User space is advised to use zram/stat, zram/io_stat and
zram/mm_stat files.Signed-off-by: Sergey Senozhatsky
Reported-by: Minchan Kim
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Per-device `zram/mm_stat' file provides mm statistics of a particular
zram device in a format similar to block layer statistics. The file
consists of a single line and represents the following stats (separated by
whitespace):orig_data_size
compr_data_size
mem_used_total
mem_limit
mem_used_max
zero_pages
num_migratedSigned-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Per-device `zram/io_stat' file provides accumulated I/O statistics of
particular zram device in a format similar to block layer statistics. The
file consists of a single line and represents the following stats
(separated by whitespace):failed_reads
failed_writes
invalid_io
notify_freeSigned-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Briefly describe exported device stat attrs in zram documentation. We
will eventually get rid of per-stat sysfs nodes and, thus, clean up
Documentation/ABI/testing/sysfs-block-zram file, which is the only source
of information about device sysfs nodes.Add `num_migrated' description, since there is no independent
`num_migrated' sysfs node (and no corresponding sysfs-block-zram entry),
it will be exported via zram/mm_stat file.At this point we can provide minimal description, because sysfs-block-zram
still contains detailed information.Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Apr, 2015
2 commits
-
Add a list of available module parameters as attachment to the
documentation.Signed-off-by: Markus Pargmann
Signed-off-by: Jens Axboe -
Reformat the existing documentation to have more structure. This allows
for more documentation seperated from the existing paragraphs.Signed-off-by: Markus Pargmann
Signed-off-by: Jens Axboe
10 Oct, 2014
2 commits
-
Normally, zram user could get maximum memory usage zram consumed via
polling mem_used_total with sysfs in userspace.But it has a critical problem because user can miss peak memory usage
during update inverval of polling. For avoiding that, user should poll it
with shorter interval(ie, 0.0000000001s) with mlocking to avoid page fault
delay when memory pressure is heavy. It would be troublesome.This patch adds new knob "mem_used_max" so user could see the maximum
memory usage easily via reading the knob and reset it via "echo 0 >
/sys/block/zram0/mem_used_max".Signed-off-by: Minchan Kim
Reviewed-by: Dan Streetman
Cc: Sergey Senozhatsky
Cc: Jerome Marchand
Cc:
Cc:
Cc: Luigi Semenzato
Cc: Nitin Gupta
Cc: Seth Jennings
Reviewed-by: David Horner
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since zram has no control feature to limit memory usage, it makes hard to
manage system memrory.This patch adds new knob "mem_limit" via sysfs to set up the a limit so
that zram could fail allocation once it reaches the limit.In addition, user could change the limit in runtime so that he could
manage the memory more dynamically.Initial state is no limit so it doesn't break old behavior.
[akpm@linux-foundation.org: fix typo, per Sergey]
Signed-off-by: Minchan Kim
Cc: Dan Streetman
Cc: Sergey Senozhatsky
Cc: Jerome Marchand
Cc:
Cc:
Cc: Luigi Semenzato
Cc: Nitin Gupta
Cc: Seth Jennings
Cc: David Horner
Cc: Joonsoo Kim
Cc: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Apr, 2014
5 commits
-
When we initialized zcomp with single, we couldn't change
max_comp_streams without zram reset but current interface doesn't show
any error to user and even it changes max_comp_streams's value without
any effect so it would make user very confusing.This patch prevents max_comp_streams's change when zcomp was initialized
as single zcomp and emit the error to user(ex, echo).[akpm@linux-foundation.org: don't return with the lock held, per Sergey]
[fengguang.wu@intel.com: fix coccinelle warnings]
Signed-off-by: Minchan Kim
Cc: Nitin Gupta
Cc: Jerome Marchand
Acked-by: Sergey Senozhatsky
Signed-off-by: Fengguang Wu
Cc: Stephen Rothwell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add and document `comp_algorithm' device attribute. This attribute allows
to show supported compression and currently selected compression
algorithms:cat /sys/block/zram0/comp_algorithm
[lzo] lz4and change selected compression algorithm:
echo lzo > /sys/block/zram0/comp_algorithmSigned-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Jerome Marchand
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Existing zram (zcomp) implementation has only one compression stream
(buffer and algorithm private part), so in order to prevent data
corruption only one write (compress operation) can use this compression
stream, forcing all concurrent write operations to wait for stream lock
to be released. This patch changes zcomp to keep a compression streams
list of user-defined size (via sysfs device attr). Each write operation
still exclusively holds compression stream, the difference is that we
can have N write operations (depending on size of streams list)
executing in parallel. See TEST section later in commit message for
performance data.Introduce struct zcomp_strm_multi and a set of functions to manage
zcomp_strm stream access. zcomp_strm_multi has a list of idle
zcomp_strm structs, spinlock to protect idle list and wait queue, making
it possible to perform parallel compressions.The following set of functions added:
- zcomp_strm_multi_find()/zcomp_strm_multi_release()
find and release a compression stream, implement required locking
- zcomp_strm_multi_create()/zcomp_strm_multi_destroy()
create and destroy zcomp_strm_multizcomp ->strm_find() and ->strm_release() callbacks are set during
initialisation to zcomp_strm_multi_find()/zcomp_strm_multi_release()
correspondingly.Each time zcomp issues a zcomp_strm_multi_find() call, the following set
of operations performed:- spin lock strm_lock
- if idle list is not empty, remove zcomp_strm from idle list, spin
unlock and return zcomp stream pointer to caller
- if idle list is empty, current adds itself to wait queue. it will be
awaken by zcomp_strm_multi_release() caller.zcomp_strm_multi_release():
- spin lock strm_lock
- add zcomp stream to idle list
- spin unlock, wake up sleeperMinchan Kim reported that spinlock-based locking scheme has demonstrated
a severe perfomance regression for single compression stream case,
comparing to mutex-based (see https://lkml.org/lkml/2014/2/18/16)base spinlock mutex
==Initial write ==Initial write ==Initial write
records: 5 records: 5 records: 5
avg: 1642424.35 avg: 699610.40 avg: 1655583.71
std: 39890.95(2.43%) std: 232014.19(33.16%) std: 52293.96
max: 1690170.94 max: 1163473.45 max: 1697164.75
min: 1568669.52 min: 573429.88 min: 1553410.23
==Rewrite ==Rewrite ==Rewrite
records: 5 records: 5 records: 5
avg: 1611775.39 avg: 501406.64 avg: 1684419.11
std: 17144.58(1.06%) std: 15354.41(3.06%) std: 18367.42
max: 1641800.95 max: 531356.78 max: 1706445.84
min: 1593515.27 min: 488817.78 min: 1655335.73When only one compression stream available, mutex with spin on owner
tends to perform much better than frequent wait_event()/wake_up(). This
is why single stream implemented as a special case with mutex locking.Introduce and document zram device attribute max_comp_streams. This
attr shows and stores current zcomp's max number of zcomp streams
(max_strm). Extend zcomp's zcomp_create() with `max_strm' parameter.
`max_strm' limits the number of zcomp_strm structs in compression
backend's idle list (max_comp_streams).max_comp_streams used during initialisation as follows:
-- passing to zcomp_create() max_strm equals to 1 will initialise zcomp
using single compression stream zcomp_strm_single (mutex-based locking).
-- passing to zcomp_create() max_strm greater than 1 will initialise zcomp
using multi compression stream zcomp_strm_multi (spinlock-based locking).default max_comp_streams value is 1, meaning that zram with single stream
will be initialised.Later patch will introduce configuration knob to change max_comp_streams
on already initialised and used zcomp.TEST
iozone -t 3 -R -r 16K -s 60M -I +Ztest base 1 strm (mutex) 3 strm (spinlock)
-----------------------------------------------------------------------
Initial write 589286.78 583518.39 718011.05
Rewrite 604837.97 596776.38 1515125.72
Random write 584120.11 595714.58 1388850.25
Pwrite 535731.17 541117.38 739295.27
Fwrite 1418083.88 1478612.72 1484927.06Usage example:
set max_comp_streams to 4
echo 4 > /sys/block/zram0/max_comp_streamsshow current max_comp_streams (default value is 1).
cat /sys/block/zram0/max_comp_streamsSigned-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Jerome Marchand
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Document `failed_reads' and `failed_writes' device attributes.
Remove info about `discard' - there is no such zram attr.Signed-off-by: Sergey Senozhatsky
Cc: Minchan Kim
Cc: Jerome Marchand
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move zram warning about disksize and size of memory correlation to zram
documentation.Signed-off-by: Sergey Senozhatsky
Acked-by: Minchan Kim
Cc: Jerome Marchand
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Feb, 2014
1 commit
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The following commits will successively transform DRBD into the structure
described here.Signed-off-by: Andreas Gruenbacher
Signed-off-by: Philipp Reisner
31 Jan, 2014
2 commits
-
Remove the old private compcache project address so upcoming patches
should be sent to LKML because we Linux kernel community will take care.Signed-off-by: Minchan Kim
Cc: Nitin Gupta
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Zram has lived in staging for a LONG LONG time and have been
fixed/improved by many contributors so code is clean and stable now. Of
course, there are lots of product using zram in real practice.The major TV companys have used zram as swap since two years ago and
recently our production team released android smart phone with zram
which is used as swap, too and recently Android Kitkat start to use zram
for small memory smart phone. And there was a report Google released
their ChromeOS with zram, too and cyanogenmod have been used zram long
time ago. And I heard some disto have used zram block device for tmpfs.
In addition, I saw many report from many other peoples. For example,
Lubuntu start to use it.The benefit of zram is very clear. With my experience, one of the
benefit was to remove jitter of video application with backgroud memory
pressure. It would be effect of efficient memory usage by compression
but more issue is whether swap is there or not in the system. Recent
mobile platforms have used JAVA so there are many anonymous pages. But
embedded system normally are reluctant to use eMMC or SDCard as swap
because there is wear-leveling and latency issues so if we do not use
swap, it means we can't reclaim anoymous pages and at last, we could
encounter OOM kill. :(Although we have real storage as swap, it was a problem, too. Because
it sometime ends up making system very unresponsible caused by slow swap
storage performance.Quote from Luigi on Google
"Since Chrome OS was mentioned: the main reason why we don't use swap
to a disk (rotating or SSD) is because it doesn't degrade gracefully
and leads to a bad interactive experience. Generally we prefer to
manage RAM at a higher level, by transparently killing and restarting
processes. But we noticed that zram is fast enough to be competitive
with the latter, and it lets us make more efficient use of the
available RAM. " and he announced.
http://www.spinics.net/lists/linux-mm/msg57717.htmlOther uses case is to use zram for block device. Zram is block device
so anyone can format the block device and mount on it so some guys on
the internet start zram as /var/tmp.
http://forums.gentoo.org/viewtopic-t-838198-start-0.htmlLet's promote zram and enhance/maintain it instead of removing.
Signed-off-by: Minchan Kim
Reviewed-by: Konrad Rzeszutek Wilk
Acked-by: Nitin Gupta
Acked-by: Pekka Enberg
Cc: Bob Liu
Cc: Greg Kroah-Hartman
Cc: Hugh Dickins
Cc: Jens Axboe
Cc: Luigi Semenzato
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Seth Jennings
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Jan, 2014
1 commit
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- ramdisk_blocksize doesn't exist anymore
- Module parameters added to documentation
Signed-off-by: Fabian Frederick
Acked-by: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Nov, 2013
1 commit
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The options have to be passed space-separated and prefixed by "floppy=",
rather than separately and unprefixed.This fixes .
Signed-off-by: Ben Harris
Signed-off-by: Jiri Kosina
28 Feb, 2013
1 commit
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Documentation/blockdev/nbd.txt contained some documentation which was
horribly outdated and probably still dates from the original patch that
added NBD support to the kernel.This patch removes the useless and outdated bits. The tools on nbd.sf.net
are fully documented in manpages, which is where documentation for the
non-kernel bits should live.Additionally, add a reference to the MAINTAINERS file for the nbd-general
mailinglist that is used for discussion of the userland tools and the
kernel module already.Signed-off-by: Wouter Verhelst
Cc: Paul Clements
Cc: Paolo Bonzini
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 Mar, 2012
1 commit
-
Usage of /etc/modprobe.conf file was deprecated by module-init-tools and
is no longer parsed by new kmod tool. References to this file are
replaced in Documentation, comments and Kconfig according to the
context.There are also some references to the old /etc/modules.conf from 2.4
kernels that are being removed.Signed-off-by: Lucas De Marchi
Acked-by: Takashi Iwai
Acked-by: Mauro Carvalho Chehab
Signed-off-by: Randy Dunlap
Signed-off-by: Linus Torvalds
