aboutsummaryrefslogtreecommitdiff
path: root/Documentation/ABI
Commit message (Collapse)AuthorAgeFilesLines
* Finally eradicate CONFIG_HOTPLUGStephen Rothwell2017-12-221-4/+1
| | | | | | | | | | | | | | | | | | | Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"), it has been basically impossible to build a kernel with CONFIG_HOTPLUG turned off. Remove all the remaining references to it. Cc: Russell King <linux@arm.linux.org.uk> Cc: Doug Thompson <dougthompson@xmission.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* f2fs: introduce gc_urgent mode for background GCJaegeuk Kim2017-10-041-0/+12
| | | | | | | | | This patch adds a sysfs entry to control urgent mode for background GC. If this is set, background GC thread conducts GC with gc_urgent_sleep_time all the time. Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
* zram: introduce per-device debug_stat sysfs nodeSergey Senozhatsky2017-09-251-0/+9
| | | | | | | | | | | | | | | | | | | | | 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 <sergey.senozhatsky@gmail.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: add dynamic device add/remove functionalitySergey Senozhatsky2017-09-251-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 device hot_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_remove Returning 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 memory NOTE, 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 <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* block: zram: Backport from Linux 4.1Sultan Qasim Khan2017-09-251-17/+56
| | | | Change-Id: I23f6f75979077992298d848efd79a6efc0d776bd
* FROMLIST: f2fs: introduce discard_granularity sysfs entryChao Yu2017-09-081-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (url: https://patchwork.kernel.org/patch/9876921/) Commit d618ebaf0aa8 ("f2fs: enable small discard by default") enables f2fs to issue 4K size discard in real-time discard mode. However, issuing smaller discard may cost more lifetime but releasing less free space in flash device. Since f2fs has ability of separating hot/cold data and garbage collection, we can expect that small-sized invalid region would expand soon with OPU, deletion or garbage collection on valid datas, so it's better to delay or skip issuing smaller size discards, it could help to reduce overmuch consumption of IO bandwidth and lifetime of flash storage. This patch makes f2fs selectng 64K size as its default minimal granularity, and issue discard with the size which is not smaller than minimal granularity. Also it exposes discard granularity as sysfs entry for configuration in different scenario. Jaegeuk Kim: We must issue all the accumulated discard commands when fstrim is called. So, I've added pend_list_tag[] to indicate whether we should issue the commands or not. If tag sets P_ACTIVE or P_TRIM, we have to issue them. P_TRIM is set once at a time, given fstrim trigger. In addition, issue_discard_thread is calling too much due to the number of discard commands remaining in the pending list. I added a timer to control it likewise gc_thread. Change-Id: Ia90dd686c25cb27f144137ea3c9bcc1c943a9aea Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
* f2fs: introduce reserved_blocks in sysfsChao Yu2017-07-211-0/+18
| | | | | | | | | | | | | | | | In this patch, we add a new sysfs interface, with it, we can control number of reserved blocks in system which could not be used by user, it enable f2fs to let user to configure for adjusting over-provision ratio dynamically instead of changing it by mkfs. So we can expect it will help to reserve more free space for relieving GC in both filesystem and flash device. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Conflicts: Documentation/ABI/testing/sysfs-fs-f2fs
* f2fs: introduce lifetime write IO statisticsShuoran Liu2017-04-131-0/+6
| | | | | | | | | | | This patch introduces lifetime IO write statistics exposed to the sysfs interface. The write IO amount is obtained from block layer, accumulated in the file system and stored in the hot node summary of checkpoint. Signed-off-by: Shuoran Liu <liushuoran@huawei.com> Signed-off-by: Pengyang Hou <houpengyang@huawei.com> [Jaegeuk Kim: add sysfs documentation] Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
* f2fs: export dirty_nats_ratio in sysfsChao Yu2017-04-131-0/+8
| | | | | | | | | | | | This patch exports a new sysfs entry 'dirty_nat_ratio' to control threshold of dirty nat entries, if current ratio exceeds configured threshold, checkpoint will be triggered in f2fs_balance_fs_bg for flushing dirty nats. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Conflicts: Documentation/ABI/testing/sysfs-fs-f2fs
* f2fs: detect idle time depending on user behaviorJaegeuk Kim2017-04-131-0/+100
| | | | | | | | | | This patch adds last time that user requested filesystem operations. This information is used to detect whether system is idle or not later. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Conflicts: Documentation/ABI/testing/sysfs-fs-f2fs
* Power: Report suspend times from last_suspend_timejinqian2017-04-111-0/+16
| | | | | | | | | This node epxorts two values separated by space. From left to right: 1. time spent in suspend/resume process 2. time spent sleep in suspend state Change-Id: I2cb9a9408a5fd12166aaec11b935a0fd6a408c63
* zram: make compression algorithm selection possibleSergey Senozhatsky2016-12-111-0/+8
| | | | | | | | | | | | | | | | | | | 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] lz4 and change selected compression algorithm: echo lzo > /sys/block/zram0/comp_algorithm Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: add multi stream functionalitySergey Senozhatsky2016-12-111-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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_multi zcomp ->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 sleeper Minchan 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: 1655335.73 When 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 +Z test 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 1484927.06 Usage example: set max_comp_streams to 4 echo 4 > /sys/block/zram0/max_comp_streams show current max_comp_streams (default value is 1). cat /sys/block/zram0/max_comp_streams Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Conflicts: Documentation/ABI/testing/sysfs-block-zram
* first commitMeizu OpenSource2016-08-15178-0/+11294