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* mediatek drv_wlan: WLAN/WIFI RX EnhanceDerTeufel2016-12-191-1/+1
| | | | | dragonpt committed 9e6b229 2015-05-15
* net: dhcpv6: remove MTK_DHCPV6C_WIFI featureYingjoe Chen2016-12-198-58/+0
| | | | | | | | | | | | MTK extension MTK_DHCPV6C_WIFI is no longer necessary. Remove option and functionality. This reverts commit ccd52552b0ef ("HPV6: fix HPv6 onfig Error") and 4996bbf5c24b ("DHCPV6:Support DHCPV6 to Assign IPV6 Address") Change-Id: I3a1ea546bd4006546a301e0fc0fed721ae5c507f CR-Id: ALPS02210363 Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
* revert "Network: reset onnection by UID"Yingjoe Chen2016-12-194-142/+0
| | | | | | | | This reverts commit 3860aeacee01 ("Network:Reset Connection by UID") Change-Id: I842aec64f563ba9d0b2b6f460b6d683bde30361e CR-Id: ALPS02210363 Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
* tcp: Change default TCP Cong. to Westwoodcm2016-12-114-8/+52
| | | | tcp: Change default TCP Cong. to Westwood
* block: Adding ROW scheduling algorithmAndrei F2016-12-114-15/+154
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Squashed commit of the following: commit f49e14ccdcb6694ed27754e020057d27a8fcca07 Author: Andrei F <luxneb@gmail.com> Date: Thu Nov 26 22:40:38 2015 +0100 elevator: Fix a race in elevator switching commit d50235b7bc3ee0a0427984d763ea7534149531b4 upstream. There's a race between elevator switching and normal io operation. Because the allocation of struct elevator_queue and struct elevator_data don't in a atomic operation.So there are have chance to use NULL ->elevator_data. For example: Thread A: Thread B blk_queu_bio elevator_switch spin_lock_irq(q->queue_block) elevator_alloc elv_merge elevator_init_fn Because call elevator_alloc, it can't hold queue_lock and the ->elevator_data is NULL.So at the same time, threadA call elv_merge and nedd some info of elevator_data.So the crash happened. Move the elevator_alloc into func elevator_init_fn, it make the operations in a atomic operation. Using the follow method can easy reproduce this bug 1:dd if=/dev/sdb of=/dev/null 2:while true;do echo noop > scheduler;echo deadline > scheduler;done The test method also use this method. Signed-off-by: Jianpeng Ma <majianpeng@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Jonghwan Choi <jhbird.choi@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> commit daf22a727e64f1277b074442efb821366015ca72 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Jul 25 13:45:21 2013 +0300 block: row: Remove warning massage from add_request Regular priority queues is marked as "starved" if it skipped a dispatch due to being empty. When a new request is added to a "starved" queue it will be marked as urgent. The removed WARN_ON was warning about an impossible case when a regular priority (read) queue was marked as starved but wasn't empty. This is a possible case due to the bellow: If the device driver fetched a read request that is pending for transmission and an URGENT request arrives, the fetched read will be reinserted back to the scheduler. Its possible that the queue it will be reinserted to was marked as "starved" in the meanwhile due to being empty. CRs-fixed: 517800 Change-Id: Iaae642ea0ed9c817c41745b0e8ae2217cc684f0c Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit dca47e75f1413d58e4f97ef638e5d4456c55bdce Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Jul 2 14:43:13 2013 +0300 block: row: change hrtimer_cancel to hrtimer_try_to_cancel Calling hrtimer_cancel with interrupts disabled can result in a livelock. When flushing plug list in the block layer interrupts are disabled and an hrtimer is used when adding requests from that plug list to the scheduler. In this code flow, if the hrtimer (which is used for idling) is set, it's being canceled by calling hrtimer_cancel. hrtimer_cancel will perform the following in an endless loop: 1. try cancel the timer 2. if fails - rest_cpu the cancellation can fail if the timer function already started. Since interrupts are disabled it can never complete. This patch reduced the number of times the hrtimer lock is taken while interrupts are disabled by calling hrtimer_try_co_cancel. the later will try to cancel the timer just once and return with an error code if fails. CRs-fixed: 499887 Change-Id: I25f79c357426d72ad67c261ce7cb503ae97dc7b9 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit a6047b9d808eaa787e4df3107bea7536334856cd Author: Lee Susman <lsusman@codeaurora.org> Date: Sun Jun 23 16:27:40 2013 +0300 block: row-iosched idling triggered by readahead pages In the current implementation idling is triggered only by request insertion frequency. This heuristic is not very accurate and may hit random requests that shouldn't trigger idling. This patch uses the PG_readahead flag in struct page's flags, which indicates that the page is part of a readahead window, to start idling upon dispatch of a request associated with a readahead page. The above readehead flag is used together with the existing insertion-frequency trigger. The frequency timer will catch read requests which are not part of a readahead window, but are still part of a sequential stream (and therefore dispatched in small time intervals). Change-Id: Icb7145199c007408de3f267645ccb842e051fd00 Signed-off-by: Lee Susman <lsusman@codeaurora.org> commit e70e4e8e1d1f111023dd2b2d0fc9237240cab9ab Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Wed May 1 14:35:20 2013 +0300 block: urgent: Fix dispatching of URGENT mechanism There are cases when blk_peek_request is called not from blk_fetch_request thus the URGENT request may be started but the flag q->dispatched_urgent is not updated. Change-Id: I4fb588823f1b2949160cbd3907f4729767932e12 CRs-fixed: 471736 CRs-fixed: 473036 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 0e36870f6a436840eed1782d0e85b4adb300b59f Author: Maya Erez <merez@codeaurora.org> Date: Sun Apr 14 15:19:52 2013 +0300 block: row: Fix starvation tolerance values The current starvation tolerance values increase the boot time since high priority SW requests are delayed by regular priority requests. In order to overcome this, increase the starvation tolerance values. Change-Id: I9947fca9927cbd39a1d41d4bd87069df679d3103 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Signed-off-by: Maya Erez <merez@codeaurora.org> commit 3cab8d28e735fdad300eda3bed703129ba05d70a Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Apr 11 14:57:15 2013 +0300 block: urgent request: Update dispatch_urgent in case of requeue/reinsert The block layer implements a mechanism for verifying that the device driver won't be notified of an URGENT request if there is already an URGENT request in flight. This is due to the fact that interrupting an URGENT request isn't efficient. This patch fixes the above described mechanism in case the URGENT request was returned back to the block layer from some reason: by requeue or reinsert. CRs-fixed: 473376, 473036, 471736 Change-Id: Ie8b8208230a302d4526068531616984825f1050d Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit e052e4574bb928b44e660b9679d23e14011b0b9d Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Mar 21 11:04:02 2013 +0200 block: row: Update sysfs functions All ROW (time related) configurable parameters are stored in ms so there is no need to convert from/to ms when reading/updating them via sysfs. Change-Id: Ib6a1de54140b5d25696743da944c076dd6fc02ae Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Conflicts: block/row-iosched.c commit 2c3203650c2109c18abb3b17a5114d54bb22e683 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Mar 21 13:02:07 2013 +0200 block: row: Prevent starvation of regular priority by high priority At the moment all REGULAR and LOW priority requests are starved as long as there are HIGH priority requests to dispatch. This patch prevents the above starvation by setting a starvation limit the REGULAR\LOW priority requests can tolerate. Change-Id: Ibe24207982c2c55d75c0b0230f67e013d1106017 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit a5434f618d395a03fe19ef430a8c5747bad069f9 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Mar 12 21:02:33 2013 +0200 block: urgent request: remove unnecessary urgent marking An urgent request is marked by the scheduler in rq->cmd_flags with the REQ_URGENT flag. There is no need to add an additional marking by the block layer. Change-Id: I05d5e9539d2f6c1bfa80240b0671db197a5d3b3f Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 3928fb74c2f78578c57913938644acb704b77586 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Mar 12 21:17:18 2013 +0200 block: row: Re-design urgent request notification mechanism When ROW scheduler reports to the block layer that there is an urgent request pending, the device driver may decide to stop the transmission of the current request in order to handle the urgent one. This is done in order to reduce the latency of an urgent request. For example: long WRITE may be stopped to handle an urgent READ. This patch updates the ROW URGENT notification policy to apply with the below: - Don't notify URGENT if there is an un-completed URGENT request in driver - After notifying that URGENT request is present, the next request dispatched is the URGENT one. - At every given moment only 1 request can be marked as URGENT. Independent of it's location (driver or scheduler) Other changes to URGENT policy: - Only READ queues are allowed to notify of an URGENT request pending. CR fix: If a pending urgent request (A) gets merged with another request (B) A is removed from scheduler queue but is not removed from rd->pending_urgent_rq. CRs-Fixed: 453712 Change-Id: I321e8cf58e12a05b82edd2a03f52fcce7bc9a900 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 8912aa92e3d919ceabc72b2eddc829fc5e4bd7eb Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Jan 24 16:17:27 2013 +0200 block: row: Update initial values of ROW data structures This patch sets the initial values of internal ROW parameters. Change-Id: I38132062a7fcbe2e58b9cc757e55caac64d013dc Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> [smuckle@codeaurora.org: ported from msm-3.7] Signed-off-by: Steve Muckle <smuckle@codeaurora.org> commit b709e1a8a56784cb83c2c31a4e7df574a6b29802 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Jan 24 15:08:40 2013 +0200 block: row: Don't notify URGENT if there are un-completed urgent req When ROW scheduler reports to the block layer that there is an urgent request pending, the device driver may decide to stop the transmission of the current request in order to handle the urgent one. If the current transmitted request is an urgent request - we don't want it to be stopped. Due to the above ROW scheduler won't notify of an urgent request if there are urgent requests in flight. Change-Id: I2fa186d911b908ec7611682b378b9cdc48637ac7 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit eba966603cc8e6f8fb418bf702f5a6eca5f56f34 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Jan 24 04:01:59 2013 +0200 block: add REQ_URGENT to request flags This patch adds a new flag to be used in cmd_flags field of struct request for marking request as urgent. Urgent request is the one that should be given priority currently handled (regular) request by the device driver. The decision of a request urgency is taken by the scheduler. Change-Id: Ic20470987ef23410f1d0324f96f00578f7df8717 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Conflicts: include/linux/blk_types.h commit 7c865ab1a9ae626d023d0b03ed7fbe5c57bcbe7c Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Jan 17 20:56:07 2013 +0200 block: row: Idling mechanism re-factoring At the moment idling in ROW is implemented by delayed work that uses jiffies granularity which is not very accurate. This patch replaces current idling mechanism implementation with hrtime API, which gives nanosecond resolution (instead of jiffies). Change-Id: I86c7b1776d035e1d81571894b300228c8b8f2d92 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 72ea1d39c04734bf5eb52117968704148d2da42f Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Wed Jan 23 17:15:49 2013 +0200 block: row: Dispatch requests according to their io-priority This patch implements "application-hints" which is a way the issuing application can notify the scheduler on the priority of its request. This is done by setting the io-priority of the request. This patch reuses an already existing mechanism of io-priorities developed for CFQ. Please refer to kernel/Documentation/block/ioprio.txt for usage example and explanations. Change-Id: I228ec8e52161b424242bb7bb133418dc8b73925a Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 9f8f3d2757788477656b1d25a3055ae11d97cee4 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Sat Jan 12 16:23:18 2013 +0200 block: row: Aggregate row_queue parameters to one structure Each ROW queues has several parameters which default values are defined in separate arrays. This patch aggregates all default values into one array. The values in question are: - is idling enabled for the queue - queue quantum - can the queue notify on urgent request Change-Id: I3821b0a042542295069b340406a16b1000873ec6 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit d84ad45f3077661cab5984cd2fb7d5ef2ff06e39 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Sat Jan 12 16:21:47 2013 +0200 block: row: fix sysfs functions - idle_time conversion idle_time was updated to be stored in msec instead of jiffies. So there is no need to convert the value when reading from user or displaying the value to him. Change-Id: I58e074b204e90a90536d32199ac668112966e9cf Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 202b21e9daf7b8a097f97f764bb4ad4712c75fa7 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Sat Jan 12 16:21:12 2013 +0200 block: row: Insert dispatch_quantum into struct row_queue There is really no point in keeping the dispatch quantum of a queue outside of it. By inserting it to the row_queue structure we spare extra level in accessing it. Change-Id: Ic77571818b643e71f9aafbb2ca93d0a92158b199 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 58ca84f091faa6ff8c4f567b158be5d38f9a5c58 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Sun Jan 13 22:04:59 2013 +0200 block: row: Add some debug information on ROW queues 1. Add a counter for number of requests on queue. 2. Add function to print queues status (number requests currently on queue and number of already dispatched requests in current dispatch cycle). Change-Id: I1e98b9ca33853e6e6a8ddc53240f6cd6981e6024 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 1bbb2c7ada5a647cab1f2306458d6cf9b821ddf7 Author: Subhash Jadavani <subhashj@codeaurora.org> Date: Thu Jan 10 02:15:13 2013 +0530 block: blk-merge: don't merge the pages with non-contiguous descriptors blk_rq_map_sg() function merges the physically contiguous pages to use same scatter-gather node without checking if their page descriptors are contiguous or not. Now when dma_map_sg() is called on the scatter gather list, it would take the base page pointer from each node (one by one) and iterates through all of the pages in same sg node by keep incrementing the base page pointer with the assumption that physically contiguous pages will have their page descriptor address contiguous which may not be true if SPARSEMEM config is enabled. So here we may end referring to invalid page descriptor. Following table shows the example of physically contiguous pages but their page descriptor addresses non-contiguous. ------------------------------------------- | Page Descriptor | Physical Address | ------------------------------------------ | 0xc1e43fdc | 0xdffff000 | | 0xc2052000 | 0xe0000000 | ------------------------------------------- With this patch, relevant blk-merge functions will also check if the physically contiguous pages are having page descriptors address contiguous or not? If not then, these pages are separated to be in different scatter-gather nodes. CRs-Fixed: 392141 Change-Id: I3601565e5569a69f06fb3af99061c4d4c23af241 Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org> Conflicts: block/blk-merge.c commit 9a9b428480c932ef8434d8b9bd3b7bafdcac3f84 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Dec 20 19:23:58 2012 +0200 row: Add support for urgent request handling This patch adds support for handling urgent requests. ROW queue can be marked as "urgent" so if it was un-served in last dispatch cycle and a request was added to it - it will trigger issuing an urgent-request-notification to the block device driver. The block device driver may choose at stop the transmission of current ongoing request to handle the urgent one. Foe example: long WRITE may be stopped to handle an urgent READ. This decreases READ latency. Change-Id: I84954c13f5e3b1b5caeadc9fe1f9aa21208cb35e Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 8d5ec526b7e70307d3c4ce587b714349f44c0be8 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Dec 6 13:17:19 2012 +0200 block:row: fix idling mechanism in ROW This patch addresses the following issues found in the ROW idling mechanism: 1. Fix the delay passed to queue_delayed_work (pass actual delay and not the time when to start the work) 2. Change the idle time and the idling-trigger frequency to be HZ dependent (instead of using msec_to_jiffies()) 3. Destroy idle_workqueue() in queue_exit Change-Id: If86513ad6b4be44fb7a860f29bd2127197d8d5bf Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Conflicts: block/row-iosched.c commit c26a95811462b9ba8eca23b4ba2150e7b660ca40 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Oct 30 08:33:06 2012 +0200 row: Adding support for reinsert already dispatched req Add support for reinserting already dispatched request back to the schedulers internal data structures. The request will be reinserted back to the queue (head) it was dispatched from as if it was never dispatched. Change-Id: I70954df300774409c25b5821465fb3aa33d8feb5 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit a1a6f09cae0149d935bcea3f20d4acb6556d68f9 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Dec 4 16:04:15 2012 +0200 block: Add API for urgent request handling This patch add support in block & elevator layers for handling urgent requests. The decision if a request is urgent or not is taken by the scheduler. Urgent request notification is passed to the underlying block device driver (eMMC for example). Block device driver may decide to interrupt the currently running low priority request to serve the new urgent request. By doing so READ latency is greatly reduced in read&write collision scenarios. Note that if the current scheduler doesn't implement the urgent request mechanism, this code path is never activated. Change-Id: I8aa74b9b45c0d3a2221bd4e82ea76eb4103e7cfa Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Conflicts: block/blk-core.c commit 4e907d9d6079629d6ce61fbdfb1a629d3587e176 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Tue Dec 4 15:54:43 2012 +0200 block: Add support for reinsert a dispatched req Add support for reinserting a dispatched request back to the scheduler's internal data structures. This capability is used by the device driver when it chooses to interrupt the current request transmission and execute another (more urgent) pending request. For example: interrupting long write in order to handle pending read. The device driver re-inserts the remaining write request back to the scheduler, to be rescheduled for transmission later on. Add API for verifying whether the current scheduler supports reinserting requests mechanism. If reinsert mechanism isn't supported by the scheduler, this code path will never be activated. Change-Id: I5c982a66b651ebf544aae60063ac8a340d79e67f Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit 0675c27faab797f7149893b84cc357aadb37c697 Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Mon Oct 15 20:56:02 2012 +0200 block: ROW: Fix forced dispatch This patch fixes forced dispatch in the ROW scheduling algorithm. When the dispatch function is called with the forced flag on, we can't delay the dispatch of the requests that are in scheduler queues. Thus, when dispatch is called with forced turned on, we need to cancel idling, or not to idle at all. Change-Id: I3aa0da33ad7b59c0731c696f1392b48525b52ddc Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> commit ce6acf59662d1bbe5663a64aef9fe1695b8bbe1b Author: Tatyana Brokhman <tlinder@codeaurora.org> Date: Thu Sep 20 10:46:10 2012 +0300 block: Adding ROW scheduling algorithm This patch adds the implementation of a new scheduling algorithm - ROW. The policy of this algorithm is to prioritize READ requests over WRITE as much as possible without starving the WRITE requests. Change-Id: I4ed52ea21d43b0e7c0769b2599779a3d3869c519 Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org> Signed-off-by: Tkkg1994 <luca.grifo@outlook.com>
* mediatek: update asf driverfire8552016-12-1134-58/+3619
| | | | Backported from 3.18 MM kernel
* ALSA: usb-audio: Fix NULL dereference in create_fixed_stream_quirk()Takashi Iwai2016-12-111-0/+6
| | | | | | | | | | | | | create_fixed_stream_quirk() may cause a NULL-pointer dereference by accessing the non-existing endpoint when a USB device with a malformed USB descriptor is used. This patch avoids it simply by adding a sanity check of bNumEndpoints before the accesses. Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=971125 Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
* ipv6: add complete rcu protection around np->optEric Dumazet2016-12-1112-51/+118
| | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 45f6fad84cc305103b28d73482b344d7f5b76f39 ] This patch addresses multiple problems : UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions while socket is not locked : Other threads can change np->opt concurrently. Dmitry posted a syzkaller (http://github.com/google/syzkaller) program desmonstrating use-after-free. Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock() and dccp_v6_request_recv_sock() also need to use RCU protection to dereference np->opt once (before calling ipv6_dup_options()) This patch adds full RCU protection to np->opt BUG: 28746669 Change-Id: I207da29ac48bb6dd7c40d65f9e27c4e3ff508da0 Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Pierre Imai <imaipi@google.com>
* packet: fix race condition in packet_set_ringPhilip Pettersson2016-12-111-6/+12
| | | | | | | | | | | | | | | | | | | | | | When packet_set_ring creates a ring buffer it will initialize a struct timer_list if the packet version is TPACKET_V3. This value can then be raced by a different thread calling setsockopt to set the version to TPACKET_V1 before packet_set_ring has finished. This leads to a use-after-free on a function pointer in the struct timer_list when the socket is closed as the previously initialized timer will not be deleted. The bug is fixed by taking lock_sock(sk) in packet_setsockopt when changing the packet version while also taking the lock at the start of packet_set_ring. Change-Id: Iec8b20f499134e1edd0f9214aa4dde477d1674e1 Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.") Signed-off-by: Philip Pettersson <philip.pettersson@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> (cherry picked from commit 6d0f35f59efd6b9f83da10f15584f00c0797a51d)
* zram: correct offset usage in zram_bio_discardWeijie Yang2016-12-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to skip the physical block(PAGE_SIZE) which is partially covered by the discard bio, so we check the remaining size and subtract it if there is a need to goto the next physical block. The current offset usage in zram_bio_discard is incorrect, it will cause its upper filesystem breakdown. Consider the following scenario: On some architecture or config, PAGE_SIZE is 64K for example, filesystem is set up on zram disk without PAGE_SIZE aligned, a discard bio leads to a offset = 4K and size=72K, normally, it should not really discard any physical block as it partially cover two physical blocks. However, with the current offset usage, it will discard the second physical block and free its memory, which will cause filesystem breakdown. This patch corrects the offset usage in zram_bio_discard. Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: support REQ_DISCARDJoonsoo Kim2016-12-111-0/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | zram is ram based block device and can be used by backend of filesystem. When filesystem deletes a file, it normally doesn't do anything on data block of that file. It just marks on metadata of that file. This behavior has no problem on disk based block device, but has problems on ram based block device, since we can't free memory used for data block. To overcome this disadvantage, there is REQ_DISCARD functionality. If block device support REQ_DISCARD and filesystem is mounted with discard option, filesystem sends REQ_DISCARD to block device whenever some data blocks are discarded. All we have to do is to handle this request. This patch implements to flag up QUEUE_FLAG_DISCARD and handle this REQ_DISCARD request. With it, we can free memory used by zram if it isn't used. [akpm@linux-foundation.org: tweak comments] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* set number of streams to 3DerTeufel2016-12-111-1/+1
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* fix buildDerTeufel2016-12-113-2/+2
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* zram: use scnprintf() in attrs show() methodsSergey Senozhatsky2016-12-112-9/+11
| | | | | | | | | | | | | | | | | | | | | sysfs.txt documentation lists the following requirements: - The buffer will always be PAGE_SIZE bytes in length. On i386, this is 4096. - show() methods should return the number of bytes printed into the buffer. This is the return value of scnprintf(). - show() should always use scnprintf(). Use scnprintf() in show() functions. 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: propagate error to userMinchan Kim2016-12-114-15/+25
| | | | | | | | | | | | | | | | | | | | | 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 <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: return error-valued pointer from zcomp_create()Sergey Senozhatsky2016-12-112-15/+18
| | | | | | | | | | | | | | | | | | | | | Instead of returning just NULL, return ERR_PTR from zcomp_create() if compressing backend creation has failed. ERR_PTR(-EINVAL) for unsupported compression algorithm request, ERR_PTR(-ENOMEM) for allocation (zcomp or compression stream) error. Perform IS_ERR() check of returned from zcomp_create() value in disksize_store() and set return code to PTR_ERR(). Change suggested by Jerome Marchand. [akpm@linux-foundation.org: clean up error recovery flow] Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Jerome Marchand <jmarchan@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: move comp allocation out of init_lockSergey Senozhatsky2016-12-111-12/+15
| | | | | | | | | | | | | | | | | | While fixing lockdep spew of ->init_lock reported by Sasha Levin [1], Minchan Kim noted [2] that it's better to move compression backend allocation (using GPF_KERNEL) out of the ->init_lock lock, same way as with zram_meta_alloc(), in order to prevent the same lockdep spew. [1] https://lkml.org/lkml/2014/2/27/337 [2] https://lkml.org/lkml/2014/3/3/32 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Minchan Kim <minchan@kernel.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: add lz4 algorithm backendSergey Senozhatsky2016-12-115-0/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce LZ4 compression backend and make it available for selection. LZ4 support is optional and requires user to set ZRAM_LZ4_COMPRESS config option. The default compression backend is LZO. TEST (x86_64, core i5, 2 cores + 2 hyperthreading, zram disk size 1G, ext4 file system, 3 compression streams) iozone -t 3 -R -r 16K -s 60M -I +Z Test LZO LZ4 ---------------------------------------------- Initial write 1642744.62 1317005.09 Rewrite 2498980.88 1800645.16 Read 3957026.38 5877043.75 Re-read 3950997.38 5861847.00 Reverse Read 2937114.56 5047384.00 Stride read 2948163.19 4929587.38 Random read 3292692.69 4880793.62 Mixed workload 1545602.62 3502940.38 Random write 2448039.75 1758786.25 Pwrite 1670051.03 1338329.69 Pread 2530682.00 5097177.62 Fwrite 3232085.62 3275942.56 Fread 6306880.25 6645271.12 So on my system LZ4 is slower in write-only tests, while it performs better in read-only and mixed (reads + writes) tests. Official LZ4 benchmarks available here http://code.google.com/p/lz4/ (linux kernel uses revision r90). 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: make compression algorithm selection possibleSergey Senozhatsky2016-12-116-11/+93
| | | | | | | | | | | | | | | | | | | 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 set_max_streams knobSergey Senozhatsky2016-12-113-3/+41
| | | | | | | | | | | | | | | | | | | | | | | This patch allows to change max_comp_streams on initialised zcomp. Introduce zcomp set_max_streams() knob, zcomp_strm_multi_set_max_streams() and zcomp_strm_single_set_max_streams() callbacks to change streams limit for zcomp_strm_multi and zcomp_strm_single, accordingly. set_max_streams for single steam zcomp does nothing. If user has lowered the limit, then zcomp_strm_multi_set_max_streams() attempts to immediately free extra streams (as much as it can, depending on idle streams availability). Note, this patch does not allow to change stream 'policy' from single to multi stream (or vice versa) on already initialised compression backend. 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 Senozhatsky2016-12-116-10/+215
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* zram: factor out single stream compressionSergey Senozhatsky2016-12-112-10/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is preparation patch to add multi stream support to zcomp. Introduce struct zcomp_strm_single and a set of functions to manage zcomp_strm stream access. zcomp_strm_single implements single compession stream, same way as current zcomp implementation. This moves zcomp_strm stream control and locking from zcomp, so compressing backend zcomp is not aware of required locking. Single and multi streams require different locking schemes. Minchan Kim reported that spinlock-based locking scheme (which is used in multi stream implementation) has demonstrated a severe perfomance regression for single compression stream case, comparing to mutex-based. see https://lkml.org/lkml/2014/2/18/16 The following set of functions added: - zcomp_strm_single_find()/zcomp_strm_single_release() find and release a compression stream, implement required locking - zcomp_strm_single_create()/zcomp_strm_single_destroy() create and destroy zcomp_strm_single New ->strm_find() and ->strm_release() callbacks added to zcomp, which are set to zcomp_strm_single_find() and zcomp_strm_single_release() during initialisation. Instead of direct locking and zcomp_strm access from zcomp_strm_find() and zcomp_strm_release(), zcomp now calls ->strm_find() and ->strm_release() correspondingly. 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: use zcomp compressing backendsSergey Senozhatsky2016-12-113-43/+36
| | | | | | | | | | | | | | | | Do not perform direct LZO compress/decompress calls, initialise and use zcomp LZO backend (single compression stream) instead. [akpm@linux-foundation.org: resolve conflicts with zram-delete-zram_init_device-fix.patch] 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: drivers/block/zram/zram_drv.c
* zram: introduce compressing backend abstractionSergey Senozhatsky2016-12-114-0/+237
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ZRAM performs direct LZO compression algorithm calls, making it the one and only option. While LZO is generally performs well, LZ4 algorithm tends to have a faster decompression (see http://code.google.com/p/lz4/ for full report) Name Ratio C.speed D.speed MB/s MB/s LZ4 (r101) 2.084 422 1820 LZO 2.06 2.106 414 600 Thus, users who have mostly read (decompress) usage scenarious or mixed workflow (writes with relatively high read ops number) will benefit from using LZ4 compression backend. Introduce compressing backend abstraction zcomp in order to support multiple compression algorithms with the following set of operations: .create .destroy .compress .decompress Schematically zram write() usually contains the following steps: 0) preparation (decompression of partioal IO, etc.) 1) lock buffer_lock mutex (protects meta compress buffers) 2) compress (using meta compress buffers) 3) alloc and map zs_pool object 4) copy compressed data (from meta compress buffers) to object allocated by 3) 5) free previous pool page, assign a new one 6) unlock buffer_lock mutex As we can see, compressing buffers must remain untouched from 1) to 4), because, otherwise, concurrent write() can overwrite data. At the same time, zram_meta must be aware of a) specific compression algorithm memory requirements and b) necessary locking to protect compression buffers. To remove requirement a) new struct zcomp_strm introduced, which contains a compress/decompress `buffer' and compression algorithm `private' part. While struct zcomp implements zcomp_strm stream handling and locking and removes requirement b) from zram meta. zcomp ->create() and ->destroy(), respectively, allocate and deallocate algorithm specific zcomp_strm `private' part. Every zcomp has zcomp stream and mutex to protect its compression stream. Stream usage semantics remains the same -- only one write can hold stream lock and use its buffers. zcomp_strm_find() turns caller into exclusive user of a stream (holding stream mutex until zram release stream), and zcomp_strm_release() makes zcomp stream available (unlock the stream mutex). Hence no concurrent write (compression) operations possible at the moment. iozone -t 3 -R -r 16K -s 60M -I +Z test base patched -------------------------------------------------- Initial write 597992.91 591660.58 Rewrite 609674.34 616054.97 Read 2404771.75 2452909.12 Re-read 2459216.81 2470074.44 Reverse Read 1652769.66 1589128.66 Stride read 2202441.81 2202173.31 Random read 2236311.47 2276565.31 Mixed workload 1423760.41 1709760.06 Random write 579584.08 615933.86 Pwrite 597550.02 594933.70 Pread 1703672.53 1718126.72 Fwrite 1330497.06 1461054.00 Fread 3922851.00 3957242.62 Usage examples: comp = zcomp_create(NAME) /* NAME e.g. "lzo" */ which initialises compressing backend if requested algorithm is supported. Compress: zstrm = zcomp_strm_find(comp) zcomp_compress(comp, zstrm, src, &dst_len) [..] /* copy compressed data */ zcomp_strm_release(comp, zstrm) Decompress: zcomp_decompress(comp, src, src_len, dst); Free compessing backend and its zcomp stream: zcomp_destroy(comp) 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: delete zram_init_device()Sergey Senozhatsky2016-12-111-11/+5
| | | | | | | | | | | | | | | | | | allocate new `zram_meta' in disksize_store() only for uninitialised zram device, saving a number of allocations and deallocations in case if disksize_store() was called on currently used device. at the same time zram_meta stack variable is not necessary, because we can set ->meta directly. there is also no need in setting QUEUE_FLAG_NONROT queue on every disksize_store(), set it once during device creation. [minchan@kernel.org: handle zram->meta alloc fail case] [minchan@kernel.org: prevent lockdep spew of init_lock] Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: move zram size warning to documentationSergey Senozhatsky2016-12-112-15/+5
| | | | | | | | | | | | Move zram warning about disksize and size of memory correlation to zram documentation. 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: drop not used table `count' memberSergey Senozhatsky2016-12-111-1/+0
| | | | | | | | | | | struct table `count' member is not used. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Acked-by: 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: report failed read and write statsSergey Senozhatsky2016-12-111-0/+4
| | | | | | | | | | | | | zram accounted but did not report numbers of failed read and write queries. make these stats available as failed_reads and failed_writes attrs. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: 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: remove zram stats code duplicationSergey Senozhatsky2016-12-111-59/+23
| | | | | | | | | | | | Introduce ZRAM_ATTR_RO macro that generates device_attribute and default ATTR show() function for existing atomic64_t zram stats. 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: use atomic64_t for all zram statsSergey Senozhatsky2016-12-112-12/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | This is a preparation patch for stats code duplication removal. 1) use atomic64_t for `pages_zero' and `pages_stored' zram stats. 2) `compr_size' and `pages_zero' struct zram_stats members did not follow the existing device attr naming scheme: zram_stats.ATTR has ATTR_show() function. rename them: -- compr_size -> compr_data_size -- pages_zero -> zero_pages Minchan Kim's note: If we really have trouble with atomic stat operation, we could change it with percpu_counter so that it could solve atomic overhead and unnecessary memory space by introducing unsigned long instead of 64bit atomic_t. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: 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: remove good and bad compress statsSergey Senozhatsky2016-12-112-13/+0
| | | | | | | | | | | | | | | | | | Remove `good' and `bad' compressed sub-requests stats. RW request may cause a number of RW sub-requests. zram used to account `good' compressed sub-queries (with compressed size less than 50% of original size), `bad' compressed sub-queries (with compressed size greater that 75% of original size), leaving sub-requests with compression size between 50% and 75% of original size not accounted and not reported. zram already accounts each sub-request's compression size so we can calculate real device compression ratio. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: 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>
* CPU hotplug: Provide lockless versions of callback registration functionsSrivatsa S. Bhat2016-12-112-2/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following method of CPU hotplug callback registration is not safe due to the possibility of an ABBA deadlock involving the cpu_add_remove_lock and the cpu_hotplug.lock. get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); The deadlock is shown below: CPU 0 CPU 1 ----- ----- Acquire cpu_hotplug.lock [via get_online_cpus()] CPU online/offline operation takes cpu_add_remove_lock [via cpu_maps_update_begin()] Try to acquire cpu_add_remove_lock [via register_cpu_notifier()] CPU online/offline operation tries to acquire cpu_hotplug.lock [via cpu_hotplug_begin()] *** DEADLOCK! *** The problem here is that callback registration takes the locks in one order whereas the CPU hotplug operations take the same locks in the opposite order. To avoid this issue and to provide a race-free method to register CPU hotplug callbacks (along with initialization of already online CPUs), introduce new variants of the callback registration APIs that simply register the callbacks without holding the cpu_add_remove_lock during the registration. That way, we can avoid the ABBA scenario. However, we will need to hold the cpu_add_remove_lock throughout the entire critical section, to protect updates to the callback/notifier chain. This can be achieved by writing the callback registration code as follows: cpu_maps_update_begin(); [ or cpu_notifier_register_begin(); see below ] for_each_online_cpu(cpu) init_cpu(cpu); /* This doesn't take the cpu_add_remove_lock */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_maps_update_done(); [ or cpu_notifier_register_done(); see below ] Note that we can't use get_online_cpus() here instead of cpu_maps_update_begin() because the cpu_hotplug.lock is dropped during the invocation of CPU_POST_DEAD notifiers, and hence get_online_cpus() cannot provide the necessary synchronization to protect the callback/notifier chains against concurrent reads and writes. On the other hand, since the cpu_add_remove_lock protects the entire hotplug operation (including CPU_POST_DEAD), we can use cpu_maps_update_begin/done() to guarantee proper synchronization. Also, since cpu_maps_update_begin/done() is like a super-set of get/put_online_cpus(), the former naturally protects the critical sections from concurrent hotplug operations. Since the names cpu_maps_update_begin/done() don't make much sense in CPU hotplug callback registration scenarios, we'll introduce new APIs named cpu_notifier_register_begin/done() and map them to cpu_maps_update_begin/done(). In summary, introduce the lockless variants of un/register_cpu_notifier() and also export the cpu_notifier_register_begin/done() APIs for use by modules. This way, we provide a race-free way to register hotplug callbacks as well as perform initialization for the CPUs that are already online. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* zram: do not pass rw argument to __zram_make_request()Sergey Senozhatsky2016-12-111-17/+12
| | | | | | | | | | | | | | | | | | | | Do not pass rw argument down the __zram_make_request() -> zram_bvec_rw() chain, decode it in zram_bvec_rw() instead. Besides, this is the place where we distinguish READ and WRITE bio data directions, so account zram RW stats here, instead of __zram_make_request(). This also allows to account a real number of zram READ/WRITE operations, not just requests (single RW request may cause a number of zram RW ops with separate locking, compression/decompression, etc). Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: 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: drivers/block/zram/zram_drv.c
* mlog_logger.c: fix build after removing zram->init_done structDerTeufel2016-12-111-1/+1
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* zram: drop `init_done' struct zram memberSergey Senozhatsky2016-12-112-11/+11
| | | | | | | | | | | | | Introduce init_done() helper function which allows us to drop `init_done' struct zram member. init_done() uses the fact that ->init_done == 1 equals to ->meta != NULL. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: 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: avoid null access when fail to alloc metaMinchan Kim2016-12-111-0/+2
| | | | | | | | | | | zram_meta_alloc could fail so caller should check it. Otherwise, your system will hang. Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove zram->lock in read path and change it with mutexMinchan Kim2016-12-112-12/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Finally, we separated zram->lock dependency from 32bit stat/ table handling so there is no reason to use rw_semaphore between read and write path so this patch removes the lock from read path totally and changes rw_semaphore with mutex. So, we could do old: read-read: OK read-write: NO write-write: NO Now: read-read: OK read-write: OK write-write: NO The below data proves mixed workload performs well 11 times and there is also enhance on write-write path because current rw-semaphore doesn't support SPIN_ON_OWNER. It's side effect but anyway good thing for us. Write-related tests perform better (from 61% to 1058%) but read path has good/bad(from -2.22% to 1.45%) but they are all marginal within stddev. CPU 12 iozone -t -T -l 12 -u 12 -r 16K -s 60M -I +Z -V 0 ==Initial write ==Initial write records: 10 records: 10 avg: 516189.16 avg: 839907.96 std: 22486.53 (4.36%) std: 47902.17 (5.70%) max: 546970.60 max: 909910.35 min: 481131.54 min: 751148.38 ==Rewrite ==Rewrite records: 10 records: 10 avg: 509527.98 avg: 1050156.37 std: 45799.94 (8.99%) std: 40695.44 (3.88%) max: 611574.27 max: 1111929.26 min: 443679.95 min: 980409.62 ==Read ==Read records: 10 records: 10 avg: 4408624.17 avg: 4472546.76 std: 281152.61 (6.38%) std: 163662.78 (3.66%) max: 4867888.66 max: 4727351.03 min: 4058347.69 min: 4126520.88 ==Re-read ==Re-read records: 10 records: 10 avg: 4462147.53 avg: 4363257.75 std: 283546.11 (6.35%) std: 247292.63 (5.67%) max: 4912894.44 max: 4677241.75 min: 4131386.50 min: 4035235.84 ==Reverse Read ==Reverse Read records: 10 records: 10 avg: 4565865.97 avg: 4485818.08 std: 313395.63 (6.86%) std: 248470.10 (5.54%) max: 5232749.16 max: 4789749.94 min: 4185809.62 min: 3963081.34 ==Stride read ==Stride read records: 10 records: 10 avg: 4515981.80 avg: 4418806.01 std: 211192.32 (4.68%) std: 212837.97 (4.82%) max: 4889287.28 max: 4686967.22 min: 4210362.00 min: 4083041.84 ==Random read ==Random read records: 10 records: 10 avg: 4410525.23 avg: 4387093.18 std: 236693.22 (5.37%) std: 235285.23 (5.36%) max: 4713698.47 max: 4669760.62 min: 4057163.62 min: 3952002.16 ==Mixed workload ==Mixed workload records: 10 records: 10 avg: 243234.25 avg: 2818677.27 std: 28505.07 (11.72%) std: 195569.70 (6.94%) max: 288905.23 max: 3126478.11 min: 212473.16 min: 2484150.69 ==Random write ==Random write records: 10 records: 10 avg: 555887.07 avg: 1053057.79 std: 70841.98 (12.74%) std: 35195.36 (3.34%) max: 683188.28 max: 1096125.73 min: 437299.57 min: 992481.93 ==Pwrite ==Pwrite records: 10 records: 10 avg: 501745.93 avg: 810363.09 std: 16373.54 (3.26%) std: 19245.01 (2.37%) max: 518724.52 max: 833359.70 min: 464208.73 min: 765501.87 ==Pread ==Pread records: 10 records: 10 avg: 4539894.60 avg: 4457680.58 std: 197094.66 (4.34%) std: 188965.60 (4.24%) max: 4877170.38 max: 4689905.53 min: 4226326.03 min: 4095739.72 Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove workqueue for freeing removed pending slotMinchan Kim2016-12-112-58/+6
| | | | | | | | | | | | | | | | | Commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity") introduced free request pending code to avoid scheduling by mutex under spinlock and it was a mess which made code lenghty and increased overhead. Now, we don't need zram->lock any more to free slot so this patch reverts it and then, tb_lock should protect it. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: introduce zram->tb_lockMinchan Kim2016-12-112-6/+23
| | | | | | | | | | | | | | | | | | | | | Currently, the zram table is protected by zram->lock but it's rather coarse-grained lock and it makes hard for scalibility. Let's use own rwlock instead of depending on zram->lock. This patch adds new locking so obviously, it would make slow but this patch is just prepartion for removing coarse-grained rw_semaphore(ie, zram->lock) which is hurdle about zram scalability. Final patch in this patchset series will remove the lock from read-path and change rw_semaphore with mutex in write path. With bonus, we could drop pending slot free mess in next patch. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: use atomic operation for statMinchan Kim2016-12-112-20/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some of fields in zram->stats are protected by zram->lock which is rather coarse-grained so let's use atomic operation without explict locking. This patch is ready for removing dependency of zram->lock in read path which is very coarse-grained rw_semaphore. Of course, this patch adds new atomic operation so it might make slow but my 12CPU test couldn't spot any regression. All gain/lose is marginal within stddev. iozone -t -T -l 12 -u 12 -r 16K -s 60M -I +Z -V 0 ==Initial write ==Initial write records: 50 records: 50 avg: 412875.17 avg: 415638.23 std: 38543.12 (9.34%) std: 36601.11 (8.81%) max: 521262.03 max: 502976.72 min: 343263.13 min: 351389.12 ==Rewrite ==Rewrite records: 50 records: 50 avg: 416640.34 avg: 397914.33 std: 60798.92 (14.59%) std: 46150.42 (11.60%) max: 543057.07 max: 522669.17 min: 304071.67 min: 316588.77 ==Read ==Read records: 50 records: 50 avg: 4147338.63 avg: 4070736.51 std: 179333.25 (4.32%) std: 223499.89 (5.49%) max: 4459295.28 max: 4539514.44 min: 3753057.53 min: 3444686.31 ==Re-read ==Re-read records: 50 records: 50 avg: 4096706.71 avg: 4117218.57 std: 229735.04 (5.61%) std: 171676.25 (4.17%) max: 4430012.09 max: 4459263.94 min: 2987217.80 min: 3666904.28 ==Reverse Read ==Reverse Read records: 50 records: 50 avg: 4062763.83 avg: 4078508.32 std: 186208.46 (4.58%) std: 172684.34 (4.23%) max: 4401358.78 max: 4424757.22 min: 3381625.00 min: 3679359.94 ==Stride read ==Stride read records: 50 records: 50 avg: 4094933.49 avg: 4082170.22 std: 185710.52 (4.54%) std: 196346.68 (4.81%) max: 4478241.25 max: 4460060.97 min: 3732593.23 min: 3584125.78 ==Random read ==Random read records: 50 records: 50 avg: 4031070.04 avg: 4074847.49 std: 192065.51 (4.76%) std: 206911.33 (5.08%) max: 4356931.16 max: 4399442.56 min: 3481619.62 min: 3548372.44 ==Mixed workload ==Mixed workload records: 50 records: 50 avg: 149925.73 avg: 149675.54 std: 7701.26 (5.14%) std: 6902.09 (4.61%) max: 191301.56 max: 175162.05 min: 133566.28 min: 137762.87 ==Random write ==Random write records: 50 records: 50 avg: 404050.11 avg: 393021.47 std: 58887.57 (14.57%) std: 42813.70 (10.89%) max: 601798.09 max: 524533.43 min: 325176.99 min: 313255.34 ==Pwrite ==Pwrite records: 50 records: 50 avg: 411217.70 avg: 411237.96 std: 43114.99 (10.48%) std: 33136.29 (8.06%) max: 530766.79 max: 471899.76 min: 320786.84 min: 317906.94 ==Pread ==Pread records: 50 records: 50 avg: 4154908.65 avg: 4087121.92 std: 151272.08 (3.64%) std: 219505.04 (5.37%) max: 4459478.12 max: 4435857.38 min: 3730512.41 min: 3101101.67 Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove unnecessary freeMinchan Kim2016-12-111-8/+0
| | | | | | | | | | | | | | | Commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity") introduced pending zram slot free in zram's write path in case of missing slot free by memory allocation failure in zram_slot_free_notify but it is not necessary because we have already freed the slot right before overwriting. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: delay pending free request in read pathMinchan Kim2016-12-111-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Sergey reported we don't need to handle pending free request every I/O so that this patch removes it in read path while we remain it in write path. Let's consider below example. Swap subsystem ask to zram "A" block free by swap_slot_free_notify but zram had been pended it without real freeing. Swap subsystem allocates "A" block for new data but request pended for a long time just handled and zram blindly free new data on the "A" block. :( That's why we couldn't remove handle pending free request right before zram-write. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: fix race between reset and flushing pending workMinchan Kim2016-12-111-2/+2
| | | | | | | | | | | | | | | | | | | Dan and Sergey reported that there is a racy between reset and flushing of pending work so that it could make oops by freeing zram->meta in reset while zram_slot_free can access zram->meta if new request is adding during the race window. This patch moves flush after taking init_lock so it prevents new request so that it closes the race. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: add copyrightMinchan Kim2016-12-112-0/+2
| | | | | | | | | | | | Add my copyright to the zram source code which I maintain. Signed-off-by: Minchan Kim <minchan@kernel.org> 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: drivers/block/zram/zram_drv.h
* zram: remove old private project commentMinchan Kim2016-12-114-9/+0
| | | | | | | | | | | | | 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 <minchan@kernel.org> 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: drivers/block/zram/zram_drv.h
* zsmalloc: Fix CPU hotplug callback registrationSrivatsa S. Bhat2016-12-111-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the zsmalloc code by using this latter form of callback registration. Cc: Nitin Gupta <ngupta@vflare.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* defconfig: add PGTABLE_MAPPINGMister Oyster2016-12-113-0/+3
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* zsmalloc: add copyrightMinchan Kim2016-12-112-0/+2
| | | | | | | | | Add my copyright to the zsmalloc source code which I maintain. Signed-off-by: Minchan Kim <minchan@kernel.org> 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: promote zram from stagingMinchan Kim2016-12-1110-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.html Other 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.html Let's promote zram and enhance/maintain it instead of removing. Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Nitin Gupta <ngupta@vflare.org> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Bob Liu <bob.liu@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Conflicts: drivers/block/Makefile
* zsmalloc: move it under mmMinchan Kim2016-12-1110-35/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves zsmalloc under mm directory. Before that, description will explain why we have needed custom allocator. Zsmalloc is a new slab-based memory allocator for storing compressed pages. It is designed for low fragmentation and high allocation success rate on large object, but <= PAGE_SIZE allocations. zsmalloc differs from the kernel slab allocator in two primary ways to achieve these design goals. zsmalloc never requires high order page allocations to back slabs, or "size classes" in zsmalloc terms. Instead it allows multiple single-order pages to be stitched together into a "zspage" which backs the slab. This allows for higher allocation success rate under memory pressure. Also, zsmalloc allows objects to span page boundaries within the zspage. This allows for lower fragmentation than could be had with the kernel slab allocator for objects between PAGE_SIZE/2 and PAGE_SIZE. With the kernel slab allocator, if a page compresses to 60% of it original size, the memory savings gained through compression is lost in fragmentation because another object of the same size can't be stored in the leftover space. This ability to span pages results in zsmalloc allocations not being directly addressable by the user. The user is given an non-dereferencable handle in response to an allocation request. That handle must be mapped, using zs_map_object(), which returns a pointer to the mapped region that can be used. The mapping is necessary since the object data may reside in two different noncontigious pages. The zsmalloc fulfills the allocation needs for zram perfectly [sjenning@linux.vnet.ibm.com: borrow Seth's quote] Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Nitin Gupta <ngupta@vflare.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Pekka Enberg <penberg@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Conflicts: mm/Kconfig mm/Makefile
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