- 24 7月, 2014 1 次提交
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由 Minchan Kim 提交于
Sasha reported lockdep warning [1] introduced by [2]. It could be fixed by doing disk revalidation out of the init_lock. It's okay because disk capacity change is protected by init_lock so that revalidate_disk always sees up-to-date value so there is no race. [1] https://lkml.org/lkml/2014/7/3/735 [2] zram: revalidate disk after capacity change Fixes 2e32baea ("zram: revalidate disk after capacity change"). Signed-off-by: NMinchan Kim <minchan@kernel.org> Reported-by: NSasha Levin <sasha.levin@oracle.com> Cc: "Alexander E. Patrakov" <patrakov@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> CC: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 7月, 2014 1 次提交
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由 Minchan Kim 提交于
Alexander reported mkswap on /dev/zram0 is failed if other process is opening the block device file. Step is as follows, 0. Reset the unused zram device. 1. Use a program that opens /dev/zram0 with O_RDWR and sleeps until killed. 2. While that program sleeps, echo the correct value to /sys/block/zram0/disksize. 3. Verify (e.g. in /proc/partitions) that the disk size is applied correctly. It is. 4. While that program still sleeps, attempt to mkswap /dev/zram0. This fails: mkswap: error: swap area needs to be at least 40 KiB When I investigated, the size get by ioctl(fd, BLKGETSIZE64, xxx) on mkswap to get a size of blockdev was zero although zram0 has right size by 2. The reason is zram didn't revalidate disk after changing capacity so that size of blockdev's inode is not uptodate until all of file is close. This patch should fix the BUG. Signed-off-by: NMinchan Kim <minchan@kernel.org> Reported-by: NAlexander E. Patrakov <patrakov@gmail.com> Tested-by: NAlexander E. Patrakov <patrakov@gmail.com> Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 6月, 2014 1 次提交
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由 Weijie Yang 提交于
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: NWeijie Yang <weijie.yang@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: NJoonsoo 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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 4月, 2014 17 次提交
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由 Joonsoo Kim 提交于
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: NJoonsoo 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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Acked-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: NFengguang Wu <fengguang.wu@intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: NJerome 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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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/2014/3/3/32Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: NMinchan Kim <minchan@kernel.org> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Acked-by: NJerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
Move zram warning about disksize and size of memory correlation to zram documentation. Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
Introduce ZRAM_ATTR_RO macro that generates device_attribute and default ATTR show() function for existing atomic64_t zram stats. Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sergey Senozhatsky 提交于
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: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 3月, 2014 1 次提交
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由 Minchan Kim 提交于
zram_meta_alloc could fail so caller should check it. Otherwise, your system will hang. Signed-off-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 31 1月, 2014 10 次提交
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
Commit a0c516cb ("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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
Commit a0c516cb ("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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Reported-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Reported-by: NDan Carpenter <dan.carpenter@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
Add my copyright to the zram source code which I maintain. Signed-off-by: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
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: NMinchan Kim <minchan@kernel.org> Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: NNitin Gupta <ngupta@vflare.org> Acked-by: NPekka 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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 11月, 2013 1 次提交
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由 Rashika Kheria 提交于
As suggested by Minchan Kim and Jerome Marchand "The code in reset_store get the block device (bdget_disk()) but it does not put it (bdput()) when it's done using it. The usage count is therefore incremented but never decremented." This patch also puts bdput() for all error cases. Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 24 11月, 2013 2 次提交
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由 Kent Overstreet 提交于
More prep work for immutable biovecs - with immutable bvecs drivers won't be able to use the biovec directly, they'll need to use helpers that take into account bio->bi_iter.bi_bvec_done. This updates callers for the new usage without changing the implementation yet. Signed-off-by: NKent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Paul Clements <Paul.Clements@steeleye.com> Cc: Jim Paris <jim@jtan.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com> Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Cc: support@lsi.com Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Quoc-Son Anh <quoc-sonx.anh@intel.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jan Kara <jack@suse.cz> Cc: linux-m68k@lists.linux-m68k.org Cc: linuxppc-dev@lists.ozlabs.org Cc: drbd-user@lists.linbit.com Cc: nbd-general@lists.sourceforge.net Cc: cbe-oss-dev@lists.ozlabs.org Cc: xen-devel@lists.xensource.com Cc: virtualization@lists.linux-foundation.org Cc: linux-raid@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: DL-MPTFusionLinux@lsi.com Cc: linux-scsi@vger.kernel.org Cc: devel@driverdev.osuosl.org Cc: linux-fsdevel@vger.kernel.org Cc: cluster-devel@redhat.com Cc: linux-mm@kvack.org Acked-by: NGeoff Levand <geoff@infradead.org>
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由 Kent Overstreet 提交于
Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: NKent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
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- 31 10月, 2013 2 次提交
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由 Rashika Kheria 提交于
This patch fixes the bug in reset_store caused by accessing NULL pointer. The bdev gets its value from bdget_disk() which could fail when memory pressure is severe and hence can return NULL because allocation of inode in bdget could fail. Hence, this patch introduces a check for bdev to prevent reference to a NULL pointer in the later part of the code. It also removes unnecessary check of bdev for fsync_bdev(). Cc: stable <stable@vger.kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com> Acked-by: NMinchan Kim <minchan@kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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由 Rashika Kheria 提交于
This patch fixes the following Smatch warning in zram_drv.c- drivers/staging/zram/zram_drv.c:899 destroy_device() warn: variable dereferenced before check 'zram->disk' (see line 896) Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJerome Marchand <jmarchan@redhat.com> Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 17 9月, 2013 1 次提交
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由 Greg Kroah-Hartman 提交于
This reverts commit c70bda99. It's incorrect, Kay writes: Please just remove it. "devname" is meant to be used for single-instance devices with a static dev_t, never for things like zramX. It will not do anything useful here, it does nothing really without a statically assigned dev_t, and it should not be used for devices of this kind anyway. Reported-by: NTom Gundersen <teg@jklm.no> Reported-by: NKay Sievers <kay@vrfy.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 13 8月, 2013 3 次提交
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由 Minchan Kim 提交于
[1] introduced down_write in zram_slot_free_notify to prevent race between zram_slot_free_notify and zram_bvec_[read|write]. The race could happen if somebody who has right permission to open swap device is reading swap device while it is used by swap in parallel. However, zram_slot_free_notify is called with holding spin_lock of swap layer so we shouldn't avoid holing mutex. Otherwise, lockdep warns it. This patch adds new list to handle free slot and workqueue so zram_slot_free_notify just registers slot index to be freed and registers the request to workqueue. If workqueue is expired, it holds mutex_lock so there is no problem any more. If any I/O is issued, zram handles pending slot-free request caused by zram_slot_free_notify right before handling issued request because workqueue wouldn't be expired yet so zram I/O request handling function can miss it. Lastly, when zram is reset, flush_work could handle all of pending free request so we shouldn't have memory leak. NOTE: If zram_slot_free_notify's kmalloc with GFP_ATOMIC would be failed, the slot will be freed when next write I/O write the slot. [1] [57ab0485, zram: use zram->lock to protect zram_free_page() in swap free notify path] * from v2 * refactoring * from v1 * totally redesign Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: NMinchan Kim <minchan@kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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由 Minchan Kim 提交于
[1] tried to fix invalid memory access on zram->disk but it didn't fix properly because get_disk failed during module exit path. Actually, we don't need to reset zram->disk's capacity to zero in module exit path so that this patch introduces new argument "reset_capacity" on zram_reset_divice and it only reset it when reset_store is called. [1] 6030ea9b, zram: avoid invalid memory access in zram_exit() Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: NMinchan Kim <minchan@kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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由 Kumar Gaurav 提交于
Fixed by removing trailing whitespace Signed-off-by: NKumar Gaurav <kumargauravgupta3@gmail.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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