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2022-05-19zswap: memcg accountingJohannes Weiner1-7/+30
Applications can currently escape their cgroup memory containment when zswap is enabled. This patch adds per-cgroup tracking and limiting of zswap backend memory to rectify this. The existing cgroup2 memory.stat file is extended to show zswap statistics analogous to what's in meminfo and vmstat. Furthermore, two new control files, memory.zswap.current and memory.zswap.max, are added to allow tuning zswap usage on a per-workload basis. This is important since not all workloads benefit from zswap equally; some even suffer compared to disk swap when memory contents don't compress well. The optimal size of the zswap pool, and the threshold for writeback, also depends on the size of the workload's warm set. The implementation doesn't use a traditional page_counter transaction. zswap is unconventional as a memory consumer in that we only know the amount of memory to charge once expensive compression has occurred. If zwap is disabled or the limit is already exceeded we obviously don't want to compress page upon page only to reject them all. Instead, the limit is checked against current usage, then we compress and charge. This allows some limit overrun, but not enough to matter in practice. [hannes@cmpxchg.org: fix for CONFIG_SLOB builds] Link: https://lkml.kernel.org/r/YnwD14zxYjUJPc2w@cmpxchg.org [hannes@cmpxchg.org: opt out of cgroups v1] Link: https://lkml.kernel.org/r/Yn6it9mBYFA+/lTb@cmpxchg.org Link: https://lkml.kernel.org/r/20220510152847.230957-7-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-19mm: zswap: add basic meminfo and vmstat coverageJohannes Weiner1-7/+6
Currently it requires poking at debugfs to figure out the size and population of the zswap cache on a host. There are no counters for reads and writes against the cache. As a result, it's difficult to understand zswap behavior on production systems. Print zswap memory consumption and how many pages are zswapped out in /proc/meminfo. Count zswapouts and zswapins in /proc/vmstat. Link: https://lkml.kernel.org/r/20220510152847.230957-6-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-09mm: create new mm/swap.h header fileNeilBrown1-0/+2
Patch series "MM changes to improve swap-over-NFS support". Assorted improvements for swap-via-filesystem. This is a resend of these patches, rebased on current HEAD. The only substantial changes is that swap_dirty_folio has replaced swap_set_page_dirty. Currently swap-via-fs (SWP_FS_OPS) doesn't work for any filesystem. It has previously worked for NFS but that broke a few releases back. This series changes to use a new ->swap_rw rather than ->readpage and ->direct_IO. It also makes other improvements. There is a companion series already in linux-next which fixes various issues with NFS. Once both series land, a final patch is needed which changes NFS over to use ->swap_rw. This patch (of 10): Many functions declared in include/linux/swap.h are only used within mm/ Create a new "mm/swap.h" and move some of these declarations there. Remove the redundant 'extern' from the function declarations. [akpm@linux-foundation.org: mm/memory-failure.c needs mm/swap.h] Link: https://lkml.kernel.org/r/164859751830.29473.5309689752169286816.stgit@noble.brown Link: https://lkml.kernel.org/r/164859778120.29473.11725907882296224053.stgit@noble.brown Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-03-22mm/zswap.c: allow handling just same-value filled pagesMaciej S. Szmigiero1-1/+14
Zswap has an ability to efficiently store same-value filled pages, which can be turned on and off using the "same_filled_pages_enabled" parameter. However, there is currently no way to enable just this (lightweight) functionality, while not making use of the whole compressed page storage machinery. Add a "non_same_filled_pages_enabled" parameter which allows disabling handling of pages that aren't same-value filled. This way zswap can be run in such lightweight same-value filled pages only mode. Link: https://lkml.kernel.org/r/7dbafa963e8bab43608189abbe2067f4b9287831.1641247624.git.maciej.szmigiero@oracle.com Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-22frontswap: remove support for multiple opsChristoph Hellwig1-2/+6
There is only a single instance of frontswap ops in the kernel, so simplify the frontswap code by removing support for multiple operations. Link: https://lkml.kernel.org/r/20211224062246.1258487-13-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Hugh Dickins <hughd@google.com> Cc: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: fix two bugs in zswap_writeback_entry()Miaohe Lin1-10/+7
In the ZSWAP_SWAPCACHE_FAIL and ZSWAP_SWAPCACHE_EXIST case, we forgot to call zpool_unmap_handle() when zpool can't sleep. And we might sleep in zswap_get_swap_cache_page() while zpool can't sleep. To fix all of these, zpool_unmap_handle() should be done before zswap_get_swap_cache_page() when zpool can't sleep. Link: https://lkml.kernel.org/r/20210522092242.3233191-4-linmiaohe@huawei.com Fixes: fc6697a89f56 ("mm/zswap: add the flag can_sleep_mapped") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Seth Jennings <sjenning@redhat.com> Cc: Tian Tao <tiantao6@hisilicon.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: avoid unnecessary copy-in at map timeMiaohe Lin1-1/+1
The buf mapped via zpool_map_handle() is only used to store compressed page buffer and there is no information to extract from it. So we could use ZPOOL_MM_WO instead to avoid unnecessary copy-in at map time. Link: https://lkml.kernel.org/r/20210522092242.3233191-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Seth Jennings <sjenning@redhat.com> Cc: Tian Tao <tiantao6@hisilicon.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: remove unused function zswap_debugfs_exit()Miaohe Lin1-7/+0
Patch series "Cleanup and fixup for zswap". This series contains cleanups to remove unused function and avoid unnecessary copy-in at map time. Also this fixes two bugs in the function zswap_writeback_entry(). More details can be found in the respective changelogs. This patch (of 3): zswap_debugfs_exit() is unused, remove it. Link: https://lkml.kernel.org/r/20210522092242.3233191-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210522092242.3233191-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Tian Tao <tiantao6@hisilicon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-05mm/zswap.c: switch from strlcpy to strscpyZhiyuan Dai1-1/+1
strlcpy is marked as deprecated in Documentation/process/deprecated.rst, and there is no functional difference when the caller expects truncation (when not checking the return value). strscpy is relatively better as it also avoids scanning the whole source string. Link: https://lkml.kernel.org/r/1614227981-20367-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26mm/zswap: add the flag can_sleep_mappedTian Tao1-5/+46
Patch series "Fix the compatibility of zsmalloc and zswap". Patch #1 adds a flag to zpool, then zswap used to determine if zpool drivers such as zbud/z3fold/zsmalloc will enter an atomic context after mapping. The difference between zbud/z3fold and zsmalloc is that zsmalloc requires an atomic context that since its map function holds a preempt-disabled, but zbud/z3fold don't require an atomic context. So patch #2 sets flag sleep_mapped to true indicating that zbud/z3fold can sleep after mapping. zsmalloc didn't support sleep after mapping, so don't set that flag to true. This patch (of 2): Add a flag to zpool, named is "can_sleep_mapped", and have it set true for zbud/z3fold, not set this flag for zsmalloc, so its default value is false. Then zswap could go the current path if the flag is true; and if it's false, copy data from src to a temporary buffer, then unmap the handle, take the mutex, process the buffer instead of src to avoid sleeping function called from atomic context. [natechancellor@gmail.com: add return value in zswap_frontswap_load] Link: https://lkml.kernel.org/r/20210121214804.926843-1-natechancellor@gmail.com [tiantao6@hisilicon.com: fix potential memory leak] Link: https://lkml.kernel.org/r/1611538365-51811-1-git-send-email-tiantao6@hisilicon.com [colin.king@canonical.com: fix potential uninitialized pointer read on tmp] Link: https://lkml.kernel.org/r/20210128141728.639030-1-colin.king@canonical.com [tiantao6@hisilicon.com: fix variable 'entry' is uninitialized when used] Link: https://lkml.kernel.org/r/1611223030-58346-1-git-send-email-tiantao6@hisilicon.comLink: https://lkml.kernel.org/r/1611035683-12732-1-git-send-email-tiantao6@hisilicon.com Link: https://lkml.kernel.org/r/1611035683-12732-2-git-send-email-tiantao6@hisilicon.com Signed-off-by: Tian Tao <tiantao6@hisilicon.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by: Mike Galbraith <efault@gmx.de> Cc: Barry Song <song.bao.hua@hisilicon.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26mm: zswap: clean up confusing commentRandy Dunlap1-3/+3
Correct wording and change one duplicated word (it) to "it is". Link: https://lkml.kernel.org/r/20201221042848.13980-1-rdunlap@infradead.org Fixes: 0ab0abcf5115 ("mm/zswap: refactor the get/put routines") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Weijie Yang <weijie.yang@samsung.com> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15mm/zswap: move to use crypto_acomp API for hardware accelerationBarry Song1-46/+137
Right now, all new ZIP drivers are adapted to crypto_acomp APIs rather than legacy crypto_comp APIs. Tradiontal ZIP drivers like lz4,lzo etc have been also wrapped into acomp via scomp backend. But zswap.c is still using the old APIs. That means zswap won't be able to work on any new ZIP drivers in kernel. This patch moves to use cryto_acomp APIs to fix the disconnected bridge between new ZIP drivers and zswap. It is probably the first real user to use acomp but perhaps not a good example to demonstrate how multiple acomp requests can be executed in parallel in one acomp instance. frontswap is doing page load and store page by page synchronously. swap_writepage() depends on the completion of frontswap_store() to decide if it should call __swap_writepage() to swap to disk. However this patch creates multiple acomp instances, so multiple threads running on multiple different cpus can actually do (de)compression parallelly, leveraging the power of multiple ZIP hardware queues. This is also consistent with frontswap's page management model. The old zswap code uses atomic context and avoids the race conditions while shared resources like zswap_dstmem are accessed. Here since acomp can sleep, per-cpu mutex is used to replace preemption-disable. While it is possible to make mm/page_io.c and mm/frontswap.c support async (de)compression in some way, the entire design requires careful thinking and performance evaluation. For the first step, the base with fixed connection between ZIP drivers and zswap should be built. Link: https://lkml.kernel.org/r/20201107065332.26992-1-song.bao.hua@hisilicon.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Acked-by: Vitaly Wool <vitalywool@gmail.com> Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David S. Miller <davem@davemloft.net> Cc: Mahipal Challa <mahipalreddy2006@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Zhou Wang <wangzhou1@hisilicon.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15mm/zswap: fix passing zero to 'PTR_ERR' warningYueHaibing1-1/+1
Fix smatch warning: mm/zswap.c:425 zswap_cpu_comp_prepare() warn: passing zero to 'PTR_ERR' crypto_alloc_comp() never return NULL, use IS_ERR instead of IS_ERR_OR_NULL to fix this. Link: https://lkml.kernel.org/r/20201031055615.28080-1-yuehaibing@huawei.com Fixes: f1c54846ee45 ("zswap: dynamic pool creation") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15mm/zswap: make struct kernel_param_ops definitions constJoe Perches1-3/+3
These should be const, so make it so. Link: https://lkml.kernel.org/r/1791535ee0b00f4a5c68cc4a8adada06593ad8f1.1601770305.git.joe@perches.com Signed-off-by: Joe Perches <joe@perches.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zswap: allow setting default status, compressor and allocator in KconfigMaciej S. Szmigiero1-12/+12
The compressed cache for swap pages (zswap) currently needs from 1 to 3 extra kernel command line parameters in order to make it work: it has to be enabled by adding a "zswap.enabled=1" command line parameter and if one wants a different compressor or pool allocator than the default lzo / zbud combination then these choices also need to be specified on the kernel command line in additional parameters. Using a different compressor and allocator for zswap is actually pretty common as guides often recommend using the lz4 / z3fold pair instead of the default one. In such case it is also necessary to remember to enable the appropriate compression algorithm and pool allocator in the kernel config manually. Let's avoid the need for adding these kernel command line parameters and automatically pull in the dependencies for the selected compressor algorithm and pool allocator by adding an appropriate default switches to Kconfig. The default values for these options match what the code was using previously as its defaults. Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Link: http://lkml.kernel.org/r/20200202000112.456103-1-mail@maciej.szmigiero.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31zswap: potential NULL dereference on error in init_zswap()Dan Carpenter1-1/+2
The "pool" pointer can be NULL at the end of the init_zswap(). (We would allocate a new pool later in that situation) So in the error handling then we need to make sure pool is a valid pointer before calling "zswap_pool_destroy(pool);" because that function dereferences the argument. Link: http://lkml.kernel.org/r/20200114050902.og32fkllkod5ycf5@kili.mountain Fixes: 93d4dfa9fbd0 ("mm/zswap.c: add allocation hysteresis if pool limit is hit") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31mm/zswap.c: add allocation hysteresis if pool limit is hitVitaly Wool1-31/+54
zswap will always try to shrink pool when zswap is full. If there is a high pressure on zswap it will result in flipping pages in and out zswap pool without any real benefit, and the overall system performance will drop. The previous discussion on this subject [1] ended up with a suggestion to implement a sort of hysteresis to refuse taking pages into zswap pool until it has sufficient space if the limit has been hit. This is my take on this. Hysteresis is controlled with a sysfs-configurable parameter (namely, /sys/kernel/debug/zswap/accept_threhsold_percent). It specifies the threshold at which zswap would start accepting pages again after it became full. Setting this parameter to 100 disables the hysteresis and sets the zswap behavior to pre-hysteresis state. [1] https://lkml.org/lkml/2019/11/8/949 Link: http://lkml.kernel.org/r/20200108200118.15563-1-vitaly.wool@konsulko.com Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24zswap: do not map same object twiceVitaly Wool1-4/+3
zswap_writeback_entry() maps a handle to read swpentry first, and then in the most common case it would map the same handle again. This is ok when zbud is the backend since its mapping callback is plain and simple, but it slows things down for z3fold. Since there's hardly a point in unmapping a handle _that_ fast as zswap_writeback_entry() does when it reads swpentry, the suggestion is to keep the handle mapped till the end. Link: http://lkml.kernel.org/r/20190916004640.b453167d3556c4093af4cf7d@gmail.com Signed-off-by: Vitaly Wool <vitalywool@gmail.com> Reviewed-by: Dan Streetman <ddstreet@ieee.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitalywool@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24zswap: use movable memory if zpool support allocate movable memoryHui Zhu1-3/+5
This is the third version that was updated according to the comments from Sergey Senozhatsky https://lkml.org/lkml/2019/5/29/73 and Shakeel Butt https://lkml.org/lkml/2019/6/4/973 zswap compresses swap pages into a dynamically allocated RAM-based memory pool. The memory pool should be zbud, z3fold or zsmalloc. All of them will allocate unmovable pages. It will increase the number of unmovable page blocks that will bad for anti-fragment. zsmalloc support page migration if request movable page: handle = zs_malloc(zram->mem_pool, comp_len, GFP_NOIO | __GFP_HIGHMEM | __GFP_MOVABLE); And commit "zpool: Add malloc_support_movable to zpool_driver" add zpool_malloc_support_movable check malloc_support_movable to make sure if a zpool support allocate movable memory. This commit let zswap allocate block with gfp __GFP_HIGHMEM | __GFP_MOVABLE if zpool support allocate movable memory. Following part is test log in a pc that has 8G memory and 2G swap. Without this commit: ~# echo lz4 > /sys/module/zswap/parameters/compressor ~# echo zsmalloc > /sys/module/zswap/parameters/zpool ~# echo 1 > /sys/module/zswap/parameters/enabled ~# swapon /swapfile ~# cd /home/teawater/kernel/vm-scalability/ /home/teawater/kernel/vm-scalability# export unit_size=$((9 * 1024 * 1024 * 1024)) /home/teawater/kernel/vm-scalability# ./case-anon-w-seq 2717908992 bytes / 4826062 usecs = 549973 KB/s 2717908992 bytes / 4864201 usecs = 545661 KB/s 2717908992 bytes / 4867015 usecs = 545346 KB/s 2717908992 bytes / 4915485 usecs = 539968 KB/s 397853 usecs to free memory 357820 usecs to free memory 421333 usecs to free memory 420454 usecs to free memory /home/teawater/kernel/vm-scalability# cat /proc/pagetypeinfo Page block order: 9 Pages per block: 512 Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 1 1 1 0 2 1 1 0 1 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 1 3 Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type Unmovable 6 5 8 6 6 5 4 1 1 1 0 Node 0, zone DMA32, type Movable 25 20 20 19 22 15 14 11 11 5 767 Node 0, zone DMA32, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Unmovable 4753 5588 5159 4613 3712 2520 1448 594 188 11 0 Node 0, zone Normal, type Movable 16 3 457 2648 2143 1435 860 459 223 224 296 Node 0, zone Normal, type Reclaimable 0 0 44 38 11 2 0 0 0 0 0 Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate Node 0, zone DMA 1 7 0 0 0 0 Node 0, zone DMA32 4 1652 0 0 0 0 Node 0, zone Normal 931 1485 15 0 0 0 With this commit: ~# echo lz4 > /sys/module/zswap/parameters/compressor ~# echo zsmalloc > /sys/module/zswap/parameters/zpool ~# echo 1 > /sys/module/zswap/parameters/enabled ~# swapon /swapfile ~# cd /home/teawater/kernel/vm-scalability/ /home/teawater/kernel/vm-scalability# export unit_size=$((9 * 1024 * 1024 * 1024)) /home/teawater/kernel/vm-scalability# ./case-anon-w-seq 2717908992 bytes / 4689240 usecs = 566020 KB/s 2717908992 bytes / 4760605 usecs = 557535 KB/s 2717908992 bytes / 4803621 usecs = 552543 KB/s 2717908992 bytes / 5069828 usecs = 523530 KB/s 431546 usecs to free memory 383397 usecs to free memory 456454 usecs to free memory 224487 usecs to free memory /home/teawater/kernel/vm-scalability# cat /proc/pagetypeinfo Page block order: 9 Pages per block: 512 Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 1 1 1 0 2 1 1 0 1 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 1 3 Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type Unmovable 10 8 10 9 10 4 3 2 3 0 0 Node 0, zone DMA32, type Movable 18 12 14 16 16 11 9 5 5 6 775 Node 0, zone DMA32, type Reclaimable 0 0 0 0 0 0 0 0 0 0 1 Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA32, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Unmovable 2669 1236 452 118 37 14 4 1 2 3 0 Node 0, zone Normal, type Movable 3850 6086 5274 4327 3510 2494 1520 934 438 220 470 Node 0, zone Normal, type Reclaimable 56 93 155 124 47 31 17 7 3 0 0 Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0 Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate Node 0, zone DMA 1 7 0 0 0 0 Node 0, zone DMA32 4 1650 2 0 0 0 Node 0, zone Normal 79 2326 26 0 0 0 You can see that the number of unmovable page blocks is decreased when the kernel has this commit. Link: http://lkml.kernel.org/r/20190605100630.13293-2-teawaterz@linux.alibaba.com Signed-off-by: Hui Zhu <teawaterz@linux.alibaba.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitalywool@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-03zswap: ignore debugfs_create_dir() return valueGreg Kroah-Hartman1-2/+0
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Cc: Seth Jennings <sjenning@redhat.com> Cc: linux-mm@kvack.org Acked-by: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157Thomas Gleixner1-10/+1
Based on 3 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-28mm: convert totalram_pages and totalhigh_pages variables to atomicArun KS1-2/+2
totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-26zswap: re-check zswap_is_full() after do zswap_shrink()Li Wang1-0/+9
/sys/../zswap/stored_pages keeps rising in a zswap test with "zswap.max_pool_percent=0" parameter. But it should not compress or store pages any more since there is no space in the compressed pool. Reproduce steps: 1. Boot kernel with "zswap.enabled=1" 2. Set the max_pool_percent to 0 # echo 0 > /sys/module/zswap/parameters/max_pool_percent 3. Do memory stress test to see if some pages have been compressed # stress --vm 1 --vm-bytes $mem_available"M" --timeout 60s 4. Watching the 'stored_pages' number increasing or not The root cause is: When zswap_max_pool_percent is set to 0 via kernel parameter, zswap_is_full() will always return true due to zswap_shrink(). But if the shinking is able to reclain a page successfully the code then proceeds to compressing/storing another page, so the value of stored_pages will keep changing. To solve the issue, this patch adds a zswap_is_full() check again after zswap_shrink() to make sure it's now under the max_pool_percent, and to not compress/store if we reached the limit. Link: http://lkml.kernel.org/r/20180530103936.17812-1-liwang@redhat.com Signed-off-by: Li Wang <liwang@redhat.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Huang Ying <huang.ying.caritas@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-15mm: use octal not symbolic permissionsJoe Perches1-19/+19
mm/*.c files use symbolic and octal styles for permissions. Using octal and not symbolic permissions is preferred by many as more readable. https://lkml.org/lkml/2016/8/2/1945 Prefer the direct use of octal for permissions. Done using $ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c and some typing. Before: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l 44 After: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l 86 Miscellanea: o Whitespace neatening around these conversions. Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.com Signed-off-by: Joe Perches <joe@perches.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-21mm, swap, frontswap: fix THP swap if frontswap enabledHuang Ying1-0/+6
It was reported by Sergey Senozhatsky that if THP (Transparent Huge Page) and frontswap (via zswap) are both enabled, when memory goes low so that swap is triggered, segfault and memory corruption will occur in random user space applications as follow, kernel: urxvt[338]: segfault at 20 ip 00007fc08889ae0d sp 00007ffc73a7fc40 error 6 in libc-2.26.so[7fc08881a000+1ae000] #0 0x00007fc08889ae0d _int_malloc (libc.so.6) #1 0x00007fc08889c2f3 malloc (libc.so.6) #2 0x0000560e6004bff7 _Z14rxvt_wcstoutf8PKwi (urxvt) #3 0x0000560e6005e75c n/a (urxvt) #4 0x0000560e6007d9f1 _ZN16rxvt_perl_interp6invokeEP9rxvt_term9hook_typez (urxvt) #5 0x0000560e6003d988 _ZN9rxvt_term9cmd_parseEv (urxvt) #6 0x0000560e60042804 _ZN9rxvt_term6pty_cbERN2ev2ioEi (urxvt) #7 0x0000560e6005c10f _Z17ev_invoke_pendingv (urxvt) #8 0x0000560e6005cb55 ev_run (urxvt) #9 0x0000560e6003b9b9 main (urxvt) #10 0x00007fc08883af4a __libc_start_main (libc.so.6) #11 0x0000560e6003f9da _start (urxvt) After bisection, it was found the first bad commit is bd4c82c22c36 ("mm, THP, swap: delay splitting THP after swapped out"). The root cause is as follows: When the pages are written to swap device during swapping out in swap_writepage(), zswap (fontswap) is tried to compress the pages to improve performance. But zswap (frontswap) will treat THP as a normal page, so only the head page is saved. After swapping in, tail pages will not be restored to their original contents, causing memory corruption in the applications. This is fixed by refusing to save page in the frontswap store functions if the page is a THP. So that the THP will be swapped out to swap device. Another choice is to split THP if frontswap is enabled. But it is found that the frontswap enabling isn't flexible. For example, if CONFIG_ZSWAP=y (cannot be module), frontswap will be enabled even if zswap itself isn't enabled. Frontswap has multiple backends, to make it easy for one backend to enable THP support, the THP checking is put in backend frontswap store functions instead of the general interfaces. Link: http://lkml.kernel.org/r/20180209084947.22749-1-ying.huang@intel.com Fixes: bd4c82c22c367e068 ("mm, THP, swap: delay splitting THP after swapped out") Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Suggested-by: Minchan Kim <minchan@kernel.org> [put THP checking in backend] Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Shaohua Li <shli@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Shakeel Butt <shakeelb@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: <stable@vger.kernel.org> [4.14] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31zswap: only save zswap header when necessaryYu Zhao1-10/+10
We waste sizeof(swp_entry_t) for zswap header when using zsmalloc as zpool driver because zsmalloc doesn't support eviction. Add zpool_evictable() to detect if zpool is potentially evictable, and use it in zswap to avoid waste memory for zswap header. [yuzhao@google.com: The zpool->" prefix is a result of copy & paste] Link: http://lkml.kernel.org/r/20180110225626.110330-1-yuzhao@google.com Link: http://lkml.kernel.org/r/20180110224741.83751-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31zswap: same-filled pages handlingSrividya Desireddy1-5/+66
Zswap is a cache which compresses the pages that are being swapped out and stores them into a dynamically allocated RAM-based memory pool. Experiments have shown that around 10-20% of pages stored in zswap are same-filled pages (i.e. contents of the page are all same), but these pages are handled as normal pages by compressing and allocating memory in the pool. This patch adds a check in zswap_frontswap_store() to identify same-filled page before compression of the page. If the page is a same-filled page, set zswap_entry.length to zero, save the same-filled value and skip the compression of the page and alloction of memory in zpool. In zswap_frontswap_load(), check if value of zswap_entry.length is zero corresponding to the page to be loaded. If zswap_entry.length is zero, fill the page with same-filled value. This saves the decompression time during load. On a ARM Quad Core 32-bit device with 1.5GB RAM by launching and relaunching different applications, out of ~64000 pages stored in zswap, ~11000 pages were same-value filled pages (including zero-filled pages) and ~9000 pages were zero-filled pages. An average of 17% of pages(including zero-filled pages) in zswap are same-value filled pages and 14% pages are zero-filled pages. An average of 3% of pages are same-filled non-zero pages. The below table shows the execution time profiling with the patch. Baseline With patch % Improvement ----------------------------------------------------------------- *Zswap Store Time 26.5ms 18ms 32% (of same value pages) *Zswap Load Time (of same value pages) 25.5ms 13ms 49% ----------------------------------------------------------------- On Ubuntu PC with 2GB RAM, while executing kernel build and other test scripts and running multimedia applications, out of 360000 pages stored in zswap 78000(~22%) of pages were found to be same-value filled pages (including zero-filled pages) and 64000(~17%) are zero-filled pages. So an average of %5 of pages are same-filled non-zero pages. The below table shows the execution time profiling with the patch. Baseline With patch % Improvement ----------------------------------------------------------------- *Zswap Store Time 91ms 74ms 19% (of same value pages) *Zswap Load Time 50ms 7.5ms 85% (of same value pages) ----------------------------------------------------------------- *The execution times may vary with test device used. Dan said: : I did test this patch out this week, and I added some instrumentation to : check the performance impact, and tested with a small program to try to : check the best and worst cases. : : When doing a lot of swap where all (or almost all) pages are same-value, I : found this patch does save both time and space, significantly. The exact : improvement in time and space depends on which compressor is being used, : but roughly agrees with the numbers you listed. : : In the worst case situation, where all (or almost all) pages have the : same-value *except* the final long (meaning, zswap will check each long on : the entire page but then still have to pass the page to the compressor), : the same-value check is around 10-15% of the total time spent in : zswap_frontswap_store(). That's a not-insignificant amount of time, but : it's not huge. Considering that most systems will probably be swapping : pages that aren't similar to the worst case (although I don't have any : data to know that), I'd say the improvement is worth the possible : worst-case performance impact. [srividya.dr@samsung.com: add memset_l instead of for loop] Link: http://lkml.kernel.org/r/20171018104832epcms5p1b2232e2236258de3d03d1344dde9fce0@epcms5p1 Signed-off-by: Srividya Desireddy <srividya.dr@samsung.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Dinakar Reddy Pathireddy <dinakar.p@samsung.com> Cc: SHARAN ALLUR <sharan.allur@samsung.com> Cc: RAJIB BASU <rajib.basu@samsung.com> Cc: JUHUN KIM <juhunkim@samsung.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Timofey Titovets <nefelim4ag@gmail.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06mm/zswap.c: delete an error message for a failed memory allocation in ↵Markus Elfring1-3/+2
zswap_dstmem_prepare() Omit an extra message for a memory allocation failure in this function. This issue was detected by using the Coccinelle software. Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf Link: http://lkml.kernel.org/r/bae25b04-2ce2-7137-a71c-50d7b4f06431@users.sourceforge.net Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06mm/zswap.c: improve a size determination in zswap_frontswap_init()Markus Elfring1-1/+1
Replace the specification of a data structure by a pointer dereference as the parameter for the operator "sizeof" to make the corresponding size determination a bit safer according to the Linux coding style convention. Link: http://lkml.kernel.org/r/19f9da22-092b-f867-bdf6-f4dbad7ccf1f@users.sourceforge.net Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-06mm/zswap.c: delete an error message for a failed memory allocation in ↵Markus Elfring1-3/+1
zswap_pool_create() Omit an extra message for a memory allocation failure in this function. This issue was detected by using the Coccinelle software. Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf Link: http://lkml.kernel.org/r/2345aabc-ae98-1d31-afba-40a02c5baf3d@users.sourceforge.net Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27zswap: don't param_set_charp while holding spinlockDan Streetman1-7/+13
Change the zpool/compressor param callback function to release the zswap_pools_lock spinlock before calling param_set_charp, since that function may sleep when it calls kmalloc with GFP_KERNEL. While this problem has existed for a while, I wasn't able to trigger it using a tight loop changing either/both the zpool and compressor params; I think it's very unlikely to be an issue on the stable kernels, especially since most zswap users will change the compressor and/or zpool from sysfs only one time each boot - or zero times, if they add the params to the kernel boot. Fixes: c99b42c3529e ("zswap: use charp for zswap param strings") Link: http://lkml.kernel.org/r/20170126155821.4545-1-ddstreet@ieee.org Signed-off-by: Dan Streetman <dan.streetman@canonical.com> Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27zswap: clear compressor or zpool param if invalid at initDan Streetman1-12/+37
If either the compressor and/or zpool param are invalid at boot, and their default value is also invalid, set the param to the empty string to indicate there is no compressor and/or zpool configured. This allows users to check the sysfs interface to see which param needs changing. Link: http://lkml.kernel.org/r/20170124200259.16191-4-ddstreet@ieee.org Signed-off-by: Dan Streetman <dan.streetman@canonical.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27zswap: allow initialization at boot without poolDan Streetman1-12/+34
Allow zswap to initialize at boot even if it can't create its pool due to a failure to create a zpool and/or compressor. Allow those to be created later, from the sysfs module param interface. Link: http://lkml.kernel.org/r/20170124200259.16191-3-ddstreet@ieee.org Signed-off-by: Dan Streetman <dan.streetman@canonical.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03zswap: disable changing params if init failsDan Streetman1-1/+29
Add zswap_init_failed bool that prevents changing any of the module params, if init_zswap() fails, and set zswap_enabled to false. Change 'enabled' param to a callback, and check zswap_init_failed before allowing any change to 'enabled', 'zpool', or 'compressor' params. Any driver that is built-in to the kernel will not be unloaded if its init function returns error, and its module params remain accessible for users to change via sysfs. Since zswap uses param callbacks, which assume that zswap has been initialized, changing the zswap params after a failed initialization will result in WARNING due to the param callbacks expecting a pool to already exist. This prevents that by immediately exiting any of the param callbacks if initialization failed. This was reported here: https://marc.info/?l=linux-mm&m=147004228125528&w=4 And fixes this WARNING: [ 429.723476] WARNING: CPU: 0 PID: 5140 at mm/zswap.c:503 __zswap_pool_current+0x56/0x60 The warning is just noise, and not serious. However, when init fails, zswap frees all its percpu dstmem pages and its kmem cache. The kmem cache might be serious, if kmem_cache_alloc(NULL, gfp) has problems; but the percpu dstmem pages are definitely a problem, as they're used as temporary buffer for compressed pages before copying into place in the zpool. If the user does get zswap enabled after an init failure, then zswap will likely Oops on the first page it tries to compress (or worse, start corrupting memory). Fixes: 90b0fc26d5db ("zswap: change zpool/compressor at runtime") Link: http://lkml.kernel.org/r/20170124200259.16191-2-ddstreet@ieee.org Signed-off-by: Dan Streetman <dan.streetman@canonical.com> Reported-by: Marcin Miroslaw <marcin@mejor.pl> Cc: Seth Jennings <sjenning@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-02mm/zswap: Convert pool to hotplug state machineSebastian Andrzej Siewior1-65/+34
Install the callbacks via the state machine. Multi state is used to address the per-pool notifier. Uppon adding of the intance the callback is invoked for all online CPUs so the manual init can go. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-mm@kvack.org Cc: Seth Jennings <sjenning@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161126231350.10321-13-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-02mm/zswap: Convert dst-mem to hotplug state machineSebastian Andrzej Siewior1-56/+17
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-mm@kvack.org Cc: Seth Jennings <sjenning@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161126231350.10321-12-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-05-20mm/zswap: use workqueue to destroy poolDan Streetman1-4/+8
Add a work_struct to struct zswap_pool, and change __zswap_pool_empty to use the workqueue instead of using call_rcu(). When zswap destroys a pool no longer in use, it uses call_rcu() to perform the destruction/freeing. Since that executes in softirq context, it must not sleep. However, actually destroying the pool involves freeing the per-cpu compressors (which requires locking the cpu_add_remove_lock mutex) and freeing the zpool, for which the implementation may sleep (e.g. zsmalloc calls kmem_cache_destroy, which locks the slab_mutex). So if either mutex is currently taken, or any other part of the compressor or zpool implementation sleeps, it will result in a BUG(). It's not easy to reproduce this when changing zswap's params normally. In testing with a loaded system, this does not fail: $ cd /sys/module/zswap/parameters $ echo lz4 > compressor ; echo zsmalloc > zpool nor does this: $ while true ; do > echo lzo > compressor ; echo zbud > zpool > sleep 1 > echo lz4 > compressor ; echo zsmalloc > zpool > sleep 1 > done although it's still possible either of those might fail, depending on whether anything else besides zswap has locked the mutexes. However, changing a parameter with no delay immediately causes the schedule while atomic BUG: $ while true ; do > echo lzo > compressor ; echo lz4 > compressor > done This is essentially the same as Yu Zhao's proposed patch to zsmalloc, but moved to zswap, to cover compressor and zpool freeing. Fixes: f1c54846ee45 ("zswap: dynamic pool creation") Signed-off-by: Dan Streetman <ddstreet@ieee.org> Reported-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Dan Streetman <dan.streetman@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-05mm/zswap: provide unique zpool nameDan Streetman1-1/+7
Instead of using "zswap" as the name for all zpools created, add an atomic counter and use "zswap%x" with the counter number for each zpool created, to provide a unique name for each new zpool. As zsmalloc, one of the zpool implementations, requires/expects a unique name for each pool created, zswap should provide a unique name. The zsmalloc pool creation does not fail if a new pool with a conflicting name is created, unless CONFIG_ZSMALLOC_STAT is enabled; in that case, zsmalloc pool creation fails with -ENOMEM. Then zswap will be unable to change its compressor parameter if its zpool is zsmalloc; it also will be unable to change its zpool parameter back to zsmalloc, if it has any existing old zpool using zsmalloc with page(s) in it. Attempts to change the parameters will result in failure to create the zpool. This changes zswap to provide a unique name for each zpool creation. Fixes: f1c54846ee45 ("zswap: dynamic pool creation") Signed-off-by: Dan Streetman <ddstreet@ieee.org> Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Dan Streetman <dan.streetman@canonical.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-2/+2
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-12-18mm/zswap: change incorrect strncmp use to strcmpDan Streetman1-3/+3
Change the use of strncmp in zswap_pool_find_get() to strcmp. The use of strncmp is no longer correct, now that zswap_zpool_type is not an array; sizeof() will return the size of a pointer, which isn't the right length to compare. We don't need to use strncmp anyway, because the existing params and the passed in params are all guaranteed to be null terminated, so strcmp should be used. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Reported-by: Weijie Yang <weijie.yang@samsung.com> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06zswap: use charp for zswap param stringsDan Streetman1-40/+40
Instead of using a fixed-length string for the zswap params, use charp. This simplifies the code and uses less memory, as most zswap param strings will be less than the current maximum length. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06mm/zswap.c: remove unneeded initialization to NULL in zswap_entry_find_get()Alexey Klimov1-1/+1
On the next line entry variable will be re-initialized so no need to init it with NULL. Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06mm, page_alloc: distinguish between being unable to sleep, unwilling to ↵Mel Gorman1-2/+3
sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10zswap: change zpool/compressor at runtimeDan Streetman1-13/+129
Update the zpool and compressor parameters to be changeable at runtime. When changed, a new pool is created with the requested zpool/compressor, and added as the current pool at the front of the pool list. Previous pools remain in the list only to remove existing compressed pages from. The old pool(s) are removed once they become empty. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10zswap: dynamic pool creationDan Streetman1-143/+405
Add dynamic creation of pools. Move the static crypto compression per-cpu transforms into each pool. Add a pointer to zswap_entry to the pool it's in. This is required by the following patch which enables changing the zswap zpool and compressor params at runtime. [akpm@linux-foundation.org: fix merge snafus] Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm: zpool: constify the zpool_opsKrzysztof Kozlowski1-1/+1
The structure zpool_ops is not modified so make the pointer to it a pointer to const. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm: swap: zswap: maybe_preload & refactoringDmitry Safonov1-67/+6
zswap_get_swap_cache_page and read_swap_cache_async have pretty much the same code with only significant difference in return value and usage of swap_readpage. I a helper __read_swap_cache_async() with the common code. Behavior change: now zswap_get_swap_cache_page will use radix_tree_maybe_preload instead radix_tree_preload. Looks like, this wasn't changed only by the reason of code duplication. Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25zswap: runtime enable/disableDan Streetman1-7/+5
Change the "enabled" parameter to be configurable at runtime. Remove the enabled check from init(), and move it to the frontswap store() function; when enabled, pages will be stored, and when disabled, pages won't be stored. This is almost identical to Seth's patch from 2 years ago: http://lkml.iu.edu/hypermail/linux/kernel/1307.2/04289.html [akpm@linux-foundation.org: tweak documentation] Signed-off-by: Dan Streetman <ddstreet@ieee.org> Suggested-by: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-12mm/zpool: add name argument to create zpoolGanesh Mahendran1-2/+3
Currently the underlay of zpool: zsmalloc/zbud, do not know who creates them. There is not a method to let zsmalloc/zbud find which caller they belong to. Now we want to add statistics collection in zsmalloc. We need to name the debugfs dir for each pool created. The way suggested by Minchan Kim is to use a name passed by caller(such as zram) to create the zsmalloc pool. /sys/kernel/debug/zsmalloc/zram0 This patch adds an argument `name' to zs_create_pool() and other related functions. Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-13mm/zswap: delete unnecessary check before calling free_percpu()Markus Elfring1-2/+1
free_percpu() tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 06:19:42 +0000