summaryrefslogtreecommitdiff
path: root/drivers/md/bcache/btree.c
AgeCommit message (Collapse)Author
2024-06-24bcache: remove heap-related macros and switch to generic min_heapKuan-Wei Chiu
Drop the heap-related macros from bcache and replacing them with the generic min_heap implementation from include/linux. By doing so, code readability is improved by using functions instead of macros. Moreover, the min_heap implementation in include/linux adopts a bottom-up variation compared to the textbook version currently used in bcache. This bottom-up variation allows for approximately 50% reduction in the number of comparison operations during heap siftdown, without changing the number of swaps, thus making it more efficient. Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu Link: https://lkml.kernel.org/r/20240524152958.919343-16-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Reviewed-by: Ian Rogers <irogers@google.com> Acked-by: Coly Li <colyli@suse.de> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Brian Foster <bfoster@redhat.com> Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Sakai <msakai@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-28bcache: allow allocator to invalidate bucket in gcDongsheng Yang
Currently, if the gc is running, when the allocator found free_inc is empty, allocator has to wait the gc finish. Before that, the IO is blocked. But actually, there would be some buckets is reclaimable before gc, and gc will never mark this kind of bucket to be unreclaimable. So we can put these buckets into free_inc in gc running to avoid IO being blocked. Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20240528120914.28705-2-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-08bcache: fix variable length array abuse in btree_iterMatthew Mirvish
btree_iter is used in two ways: either allocated on the stack with a fixed size MAX_BSETS, or from a mempool with a dynamic size based on the specific cache set. Previously, the struct had a fixed-length array of size MAX_BSETS which was indexed out-of-bounds for the dynamically-sized iterators, which causes UBSAN to complain. This patch uses the same approach as in bcachefs's sort_iter and splits the iterator into a btree_iter with a flexible array member and a btree_iter_stack which embeds a btree_iter as well as a fixed-length data array. Cc: stable@vger.kernel.org Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039368 Signed-off-by: Matthew Mirvish <matthew@mm12.xyz> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20240509011117.2697-3-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-12-02Merge tag 'block-6.7-2023-12-01' of git://git.kernel.dk/linuxLinus Torvalds
Pull block fixes from Jens Axboe: - NVMe pull request via Keith: - Invalid namespace identification error handling (Marizio Ewan, Keith) - Fabrics keep-alive tuning (Mark) - Fix for a bad error check regression in bcache (Markus) - Fix for a performance regression with O_DIRECT (Ming) - Fix for a flush related deadlock (Ming) - Make the read-only warn on per-partition (Yu) * tag 'block-6.7-2023-12-01' of git://git.kernel.dk/linux: nvme-core: check for too small lba shift blk-mq: don't count completed flush data request as inflight in case of quiesce block: Document the role of the two attribute groups block: warn once for each partition in bio_check_ro() block: move .bd_inode into 1st cacheline of block_device nvme: check for valid nvme_identify_ns() before using it nvme-core: fix a memory leak in nvme_ns_info_from_identify() nvme: fine-tune sending of first keep-alive bcache: revert replacing IS_ERR_OR_NULL with IS_ERR
2023-12-02Merge tag 'bcachefs-2023-11-29' of https://evilpiepirate.org/git/bcachefsLinus Torvalds
Pull more bcachefs bugfixes from Kent Overstreet: - bcache & bcachefs were broken with CFI enabled; patch for closures to fix type punning - mark erasure coding as extra-experimental; there are incompatible disk space accounting changes coming for erasure coding, and I'm still seeing checksum errors in some tests - several fixes for durability-related issues (durability is a device specific setting where we can tell bcachefs that data on a given device should be counted as replicated x times) - a fix for a rare livelock when a btree node merge then updates a parent node that is almost full - fix a race in the device removal path, where dropping a pointer in a btree node to a device would be clobbered by an in flight btree write updating the btree node key on completion - fix one SRCU lock hold time warning in the btree gc code - ther's still a bunch more of these to fix - fix a rare race where we'd start copygc before initializing the "are we rw" percpu refcount; copygc would think we were already ro and die immediately * tag 'bcachefs-2023-11-29' of https://evilpiepirate.org/git/bcachefs: (23 commits) bcachefs: Extra kthread_should_stop() calls for copygc bcachefs: Convert gc_alloc_start() to for_each_btree_key2() bcachefs: Fix race between btree writes and metadata drop bcachefs: move journal seq assertion bcachefs: -EROFS doesn't count as move_extent_start_fail bcachefs: trace_move_extent_start_fail() now includes errcode bcachefs: Fix split_race livelock bcachefs: Fix bucket data type for stripe buckets bcachefs: Add missing validation for jset_entry_data_usage bcachefs: Fix zstd compress workspace size bcachefs: bpos is misaligned on big endian bcachefs: Fix ec + durability calculation bcachefs: Data update path won't accidentaly grow replicas bcachefs: deallocate_extra_replicas() bcachefs: Proper refcounting for journal_keys bcachefs: preserve device path as device name bcachefs: Fix an endianness conversion bcachefs: Start gc, copygc, rebalance threads after initing writes ref bcachefs: Don't stop copygc thread on device resize bcachefs: Make sure bch2_move_ratelimit() also waits for move_ops ...
2023-11-24bcache: revert replacing IS_ERR_OR_NULL with IS_ERRMarkus Weippert
Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") replaced IS_ERR_OR_NULL by IS_ERR. This leads to a NULL pointer dereference. BUG: kernel NULL pointer dereference, address: 0000000000000080 Call Trace: ? __die_body.cold+0x1a/0x1f ? page_fault_oops+0xd2/0x2b0 ? exc_page_fault+0x70/0x170 ? asm_exc_page_fault+0x22/0x30 ? btree_node_free+0xf/0x160 [bcache] ? up_write+0x32/0x60 btree_gc_coalesce+0x2aa/0x890 [bcache] ? bch_extent_bad+0x70/0x170 [bcache] btree_gc_recurse+0x130/0x390 [bcache] ? btree_gc_mark_node+0x72/0x230 [bcache] bch_btree_gc+0x5da/0x600 [bcache] ? cpuusage_read+0x10/0x10 ? bch_btree_gc+0x600/0x600 [bcache] bch_gc_thread+0x135/0x180 [bcache] The relevant code starts with: new_nodes[0] = NULL; for (i = 0; i < nodes; i++) { if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key))) goto out_nocoalesce; // ... out_nocoalesce: // ... for (i = 0; i < nodes; i++) if (!IS_ERR(new_nodes[i])) { // IS_ERR_OR_NULL before 028ddcac477b btree_node_free(new_nodes[i]); // new_nodes[0] is NULL rw_unlock(true, new_nodes[i]); } This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this. Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") Link: https://lore.kernel.org/all/3DF4A87A-2AC1-4893-AE5F-E921478419A9@suse.de/ Cc: stable@vger.kernel.org Cc: Zheng Wang <zyytlz.wz@163.com> Cc: Coly Li <colyli@suse.de> Signed-off-by: Markus Weippert <markus@gekmihesg.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-11-24closures: CLOSURE_CALLBACK() to fix type punningKent Overstreet
Control flow integrity is now checking that type signatures match on indirect function calls. That breaks closures, which embed a work_struct in a closure in such a way that a closure_fn may also be used as a workqueue fn by the underlying closure code. So we have to change closure fns to take a work_struct as their argument - but that results in a loss of clarity, as closure fns have different semantics from normal workqueue functions (they run owning a ref on the closure, which must be released with continue_at() or closure_return()). Thus, this patc introduces CLOSURE_CALLBACK() and closure_type() macros as suggested by Kees, to smooth things over a bit. Suggested-by: Kees Cook <keescook@chromium.org> Cc: Coly Li <colyli@suse.de> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-11-20bcache: add code comments for bch_btree_node_get() and __bch_btree_node_alloc()Coly Li
This patch adds code comments to bch_btree_node_get() and __bch_btree_node_alloc() that NULL pointer will not be returned and it is unnecessary to check NULL pointer by the callers of these routines. Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20231120052503.6122-10-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-11-20bcache: replace a mistaken IS_ERR() by IS_ERR_OR_NULL() in btree_gc_coalesce()Coly Li
Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") do the following change inside btree_gc_coalesce(), 31 @@ -1340,7 +1340,7 @@ static int btree_gc_coalesce( 32 memset(new_nodes, 0, sizeof(new_nodes)); 33 closure_init_stack(&cl); 34 35 - while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b)) 36 + while (nodes < GC_MERGE_NODES && !IS_ERR(r[nodes].b)) 37 keys += r[nodes++].keys; 38 39 blocks = btree_default_blocks(b->c) * 2 / 3; At line 35 the original r[nodes].b is not always allocatored from __bch_btree_node_alloc(), and possibly initialized as NULL pointer by caller of btree_gc_coalesce(). Therefore the change at line 36 is not correct. This patch replaces the mistaken IS_ERR() by IS_ERR_OR_NULL() to avoid potential issue. Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in node allocations") Cc: <stable@vger.kernel.org> # 6.5+ Cc: Zheng Wang <zyytlz.wz@163.com> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20231120052503.6122-9-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-11-20bcache: check return value from btree_node_alloc_replacement()Coly Li
In btree_gc_rewrite_node(), pointer 'n' is not checked after it returns from btree_gc_rewrite_node(). There is potential possibility that 'n' is a non NULL ERR_PTR(), referencing such error code is not permitted in following code. Therefore a return value checking is necessary after 'n' is back from btree_node_alloc_replacement(). Signed-off-by: Coly Li <colyli@suse.de> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20231120052503.6122-3-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-10-04bcache: dynamically allocate the md-bcache shrinkerQi Zheng
In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the md-bcache shrinker, so that it can be freed asynchronously via RCU. Then it doesn't need to wait for RCU read-side critical section when releasing the struct cache_set. Link: https://lkml.kernel.org/r/20230911094444.68966-27-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Acked-by: Muchun Song <songmuchun@bytedance.com> Cc: Coly Li <colyli@suse.de> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Anna Schumaker <anna@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bob Peterson <rpeterso@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Carlos Llamas <cmllamas@google.com> Cc: Chandan Babu R <chandan.babu@oracle.com> Cc: Chao Yu <chao@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christian Koenig <christian.koenig@amd.com> Cc: Chuck Lever <cel@kernel.org> Cc: Dai Ngo <Dai.Ngo@oracle.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Airlie <airlied@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Cc: Gao Xiang <hsiangkao@linux.alibaba.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Huang Rui <ray.huang@amd.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Jason Wang <jasowang@redhat.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Jeffle Xu <jefflexu@linux.alibaba.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kirill Tkhai <tkhai@ya.ru> Cc: Marijn Suijten <marijn.suijten@somainline.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Mike Snitzer <snitzer@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Neil Brown <neilb@suse.de> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Olga Kornievskaia <kolga@netapp.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rob Clark <robdclark@gmail.com> Cc: Rob Herring <robh@kernel.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Sean Paul <sean@poorly.run> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Song Liu <song@kernel.org> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Cc: Tom Talpey <tom@talpey.com> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Yue Hu <huyue2@coolpad.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-27Merge tag 'locking-core-2023-06-27' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double() The cmpxchg128() family of functions is basically & functionally the same as cmpxchg_double(), but with a saner interface. Instead of a 6-parameter horror that forced u128 - u64/u64-halves layout details on the interface and exposed users to complexity, fragility & bugs, use a natural 3-parameter interface with u128 types. - Restructure the generated atomic headers, and add kerneldoc comments for all of the generic atomic{,64,_long}_t operations. The generated definitions are much cleaner now, and come with documentation. - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when taking multiple locks of the same type. This gets rid of one use of lockdep_set_novalidate_class() in the bcache code. - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable shadowing generating garbage code on Clang on certain ARM builds. * tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits) locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg() locking/atomic: treewide: delete arch_atomic_*() kerneldoc locking/atomic: docs: Add atomic operations to the driver basic API documentation locking/atomic: scripts: generate kerneldoc comments docs: scripts: kernel-doc: accept bitwise negation like ~@var locking/atomic: scripts: simplify raw_atomic*() definitions locking/atomic: scripts: simplify raw_atomic_long*() definitions locking/atomic: scripts: split pfx/name/sfx/order locking/atomic: scripts: restructure fallback ifdeffery locking/atomic: scripts: build raw_atomic_long*() directly locking/atomic: treewide: use raw_atomic*_<op>() locking/atomic: scripts: add trivial raw_atomic*_<op>() locking/atomic: scripts: factor out order template generation locking/atomic: scripts: remove leftover "${mult}" locking/atomic: scripts: remove bogus order parameter locking/atomic: xtensa: add preprocessor symbols locking/atomic: x86: add preprocessor symbols locking/atomic: sparc: add preprocessor symbols locking/atomic: sh: add preprocessor symbols ...
2023-06-15bcache: fixup btree_cache_wait list damageMingzhe Zou
We get a kernel crash about "list_add corruption. next->prev should be prev (ffff9c801bc01210), but was ffff9c77b688237c. (next=ffffae586d8afe68)." crash> struct list_head 0xffff9c801bc01210 struct list_head { next = 0xffffae586d8afe68, prev = 0xffffae586d8afe68 } crash> struct list_head 0xffff9c77b688237c struct list_head { next = 0x0, prev = 0x0 } crash> struct list_head 0xffffae586d8afe68 struct list_head struct: invalid kernel virtual address: ffffae586d8afe68 type: "gdb_readmem_callback" Cannot access memory at address 0xffffae586d8afe68 [230469.019492] Call Trace: [230469.032041] prepare_to_wait+0x8a/0xb0 [230469.044363] ? bch_btree_keys_free+0x6c/0xc0 [escache] [230469.056533] mca_cannibalize_lock+0x72/0x90 [escache] [230469.068788] mca_alloc+0x2ae/0x450 [escache] [230469.080790] bch_btree_node_get+0x136/0x2d0 [escache] [230469.092681] bch_btree_check_thread+0x1e1/0x260 [escache] [230469.104382] ? finish_wait+0x80/0x80 [230469.115884] ? bch_btree_check_recurse+0x1a0/0x1a0 [escache] [230469.127259] kthread+0x112/0x130 [230469.138448] ? kthread_flush_work_fn+0x10/0x10 [230469.149477] ret_from_fork+0x35/0x40 bch_btree_check_thread() and bch_dirty_init_thread() may call mca_cannibalize() to cannibalize other cached btree nodes. Only one thread can do it at a time, so the op of other threads will be added to the btree_cache_wait list. We must call finish_wait() to remove op from btree_cache_wait before free it's memory address. Otherwise, the list will be damaged. Also should call bch_cannibalize_unlock() to release the btree_cache_alloc_lock and wake_up other waiters. Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded") Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded") Cc: stable@vger.kernel.org Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20230615121223.22502-7-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-15bcache: Fix __bch_btree_node_alloc to make the failure behavior consistentZheng Wang
In some specific situations, the return value of __bch_btree_node_alloc may be NULL. This may lead to a potential NULL pointer dereference in caller function like a calling chain : btree_split->bch_btree_node_alloc->__bch_btree_node_alloc. Fix it by initializing the return value in __bch_btree_node_alloc. Fixes: cafe56359144 ("bcache: A block layer cache") Cc: stable@vger.kernel.org Signed-off-by: Zheng Wang <zyytlz.wz@163.com> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-15bcache: Remove unnecessary NULL point check in node allocationsZheng Wang
Due to the previous fix of __bch_btree_node_alloc, the return value will never be a NULL pointer. So IS_ERR is enough to handle the failure situation. Fix it by replacing IS_ERR_OR_NULL check by an IS_ERR check. Fixes: cafe56359144 ("bcache: A block layer cache") Cc: stable@vger.kernel.org Signed-off-by: Zheng Wang <zyytlz.wz@163.com> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20230615121223.22502-5-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-24bcache: Convert to lock_cmp_fnKent Overstreet
Replace one of bcache's lockdep_set_novalidate_class() usage with the newly introduced custom lock nesting annotation. [peterz: changelog] Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Coly Li <colyli@suse.de> Link: https://lkml.kernel.org/r/20230509195847.1745548-2-kent.overstreet@linux.dev
2022-07-03mm: shrinkers: provide shrinkers with namesRoman Gushchin
Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs. This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name. In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided. The expected format is: <subsystem>-<shrinker_type>[:<instance>]-<id> For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair. After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40 [roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot <lkp@intel.com> Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-27bcache: memset on stack variables in bch_btree_check() and ↵Coly Li
bch_sectors_dirty_init() The local variables check_state (in bch_btree_check()) and state (in bch_sectors_dirty_init()) should be fully filled by 0, because before allocating them on stack, they were dynamically allocated by kzalloc(). Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20220527152818.27545-2-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-24bcache: improve multithreaded bch_btree_check()Coly Li
Commit 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded") makes bch_btree_check() to be much faster when checking all btree nodes during cache device registration. But it isn't in ideal shap yet, still can be improved. This patch does the following thing to improve current parallel btree nodes check by multiple threads in bch_btree_check(), - Add read lock to root node while checking all the btree nodes with multiple threads. Although currently it is not mandatory but it is good to have a read lock in code logic. - Remove local variable 'char name[32]', and generate kernel thread name string directly when calling kthread_run(). - Allocate local variable "struct btree_check_state check_state" on the stack and avoid unnecessary dynamic memory allocation for it. - Reduce BCH_BTR_CHKTHREAD_MAX from 64 to 12 which is enough indeed. - Increase check_state->started to count created kernel thread after it succeeds to create. - When wait for all checking kernel threads to finish, use wait_event() to replace wait_event_interruptible(). With this change, the code is more clear, and some potential error conditions are avoided. Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded") Signed-off-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220524102336.10684-2-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-03-06bcache: fixup multiple threads crashMingzhe Zou
When multiple threads to check btree nodes in parallel, the main thread wait for all threads to stop or CACHE_SET_IO_DISABLE flag: wait_event_interruptible(check_state->wait, atomic_read(&check_state->started) == 0 || test_bit(CACHE_SET_IO_DISABLE, &c->flags)); However, the bch_btree_node_read and bch_btree_node_read_done maybe call bch_cache_set_error, then the CACHE_SET_IO_DISABLE will be set. If the flag already set, the main thread return error. At the same time, maybe some threads still running and read NULL pointer, the kernel will crash. This patch change the event wait condition, the main thread must wait for all threads to stop. Fixes: 8e7102273f597 ("bcache: make bch_btree_check() to be multithreaded") Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn> Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Coly Li <colyli@suse.de>
2021-11-08bcache: Revert "bcache: use bvec_virt"Coly Li
This reverts commit 2fd3e5efe791946be0957c8e1eed9560b541fe46. The above commit replaces page_address(bv->bv_page) by bvec_virt(bv) to avoid directly access to bv->bv_page, but in situation bv->bv_offset is not zero and page_address(bv->bv_page) is not equal to bvec_virt(bv). In such case a memory corruption may happen because memory in next page is tainted by following line in do_btree_node_write(), memcpy(bvec_virt(bv), addr, PAGE_SIZE); This patch reverts the mentioned commit to avoid the memory corruption. Fixes: 2fd3e5efe791 ("bcache: use bvec_virt") Signed-off-by: Coly Li <colyli@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org # 5.15 Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20211103151041.70516-1-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20bcache: remove bch_crc64_updateChristoph Hellwig
bch_crc64_update is an entirely pointless wrapper around crc64_be. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20211020143812.6403-9-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-16bcache: use bvec_virtChristoph Hellwig
Use bvec_virt instead of open coding it. Note that the existing code is fine despite ignoring bv_offset as the bio is known to contain exactly one page from the page allocator per bio_vec. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20210804095634.460779-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-04-11bcache: remove PTR_CACHEChristoph Hellwig
Remove the PTR_CACHE inline and replace it with a direct dereference of c->cache. (Coly Li: fix the typo from PTR_BUCKET to PTR_CACHE in commit log) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Coly Li <colyli@suse.de> Link: https://lore.kernel.org/r/20210411134316.80274-3-colyli@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10bcache: Give btree_io_wq correct semantics againKai Krakow
Before killing `btree_io_wq`, the queue was allocated using `create_singlethread_workqueue()` which has `WQ_MEM_RECLAIM`. After killing it, it no longer had this property but `system_wq` is not single threaded. Let's combine both worlds and make it multi threaded but able to reclaim memory. Cc: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Kai Krakow <kai@kaishome.de> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10Revert "bcache: Kill btree_io_wq"Kai Krakow
This reverts commit 56b30770b27d54d68ad51eccc6d888282b568cee. With the btree using the `system_wq`, I seem to see a lot more desktop latency than I should. After some more investigation, it looks like the original assumption of 56b3077 no longer is true, and bcache has a very high potential of congesting the `system_wq`. In turn, this introduces laggy desktop performance, IO stalls (at least with btrfs), and input events may be delayed. So let's revert this. It's important to note that the semantics of using `system_wq` previously mean that `btree_io_wq` should be created before and destroyed after other bcache wqs to keep the same assumptions. Cc: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Kai Krakow <kai@kaishome.de> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-02bcache: remove embedded struct cache_sb from struct cache_setColy Li
Since bcache code was merged into mainline kerrnel, each cache set only as one single cache in it. The multiple caches framework is here but the code is far from completed. Considering the multiple copies of cached data can also be stored on e.g. md raid1 devices, it is unnecessary to support multiple caches in one cache set indeed. The previous preparation patches fix the dependencies of explicitly making a cache set only have single cache. Now we don't have to maintain an embedded partial super block in struct cache_set, the in-memory super block can be directly referenced from struct cache. This patch removes the embedded struct cache_sb from struct cache_set, and fixes all locations where the superb lock was referenced from this removed super block by referencing the in-memory super block of struct cache. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-02bcache: only use block_bytes() on struct cacheColy Li
Because struct cache_set and struct cache both have struct cache_sb, therefore macro block_bytes() can be used on both of them. When removing the embedded struct cache_sb from struct cache_set, this macro won't be used on struct cache_set anymore. This patch unifies all block_bytes() usage only on struct cache, this is one of the preparation to remove the embedded struct cache_sb from struct cache_set. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-02bcache: remove for_each_cache()Coly Li
Since now each cache_set explicitly has single cache, for_each_cache() is unnecessary. This patch removes this macro, and update all locations where it is used, and makes sure all code logic still being consistent. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-02bcache: remove 'int n' from parameter list of bch_bucket_alloc_set()Coly Li
The parameter 'int n' from bch_bucket_alloc_set() is not cleared defined. From the code comments n is the number of buckets to alloc, but from the code itself 'n' is the maximum cache to iterate. Indeed all the locations where bch_bucket_alloc_set() is called, 'n' is alwasy 1. This patch removes the confused and unnecessary 'int n' from parameter list of bch_bucket_alloc_set(), and explicitly allocates only 1 bucket for its caller. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-02bcache: check c->root with IS_ERR_OR_NULL() in mca_reserve()Dongsheng Yang
In mca_reserve(c) macro, we are checking root whether is NULL or not. But that's not enough, when we read the root node in run_cache_set(), if we got an error in bch_btree_node_read_done(), we will return ERR_PTR(-EIO) to c->root. And then we will go continue to unregister, but before calling unregister_shrinker(&c->shrink), there is a possibility to call bch_mca_count(), and we would get a crash with call trace like that: [ 2149.876008] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b5 ... ... [ 2150.598931] Call trace: [ 2150.606439] bch_mca_count+0x58/0x98 [escache] [ 2150.615866] do_shrink_slab+0x54/0x310 [ 2150.624429] shrink_slab+0x248/0x2d0 [ 2150.632633] drop_slab_node+0x54/0x88 [ 2150.640746] drop_slab+0x50/0x88 [ 2150.648228] drop_caches_sysctl_handler+0xf0/0x118 [ 2150.657219] proc_sys_call_handler.isra.18+0xb8/0x110 [ 2150.666342] proc_sys_write+0x40/0x50 [ 2150.673889] __vfs_write+0x48/0x90 [ 2150.681095] vfs_write+0xac/0x1b8 [ 2150.688145] ksys_write+0x6c/0xd0 [ 2150.695127] __arm64_sys_write+0x24/0x30 [ 2150.702749] el0_svc_handler+0xa0/0x128 [ 2150.710296] el0_svc+0x8/0xc Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-25bcache: handle cache set verify_ondisk properly for bucket size > 8MBColy Li
In bch_btree_cache_alloc() when CONFIG_BCACHE_DEBUG is configured, allocate memory for c->verify_ondisk may fail if the bucket size > 8MB, which will require __get_free_pages() to allocate continuous pages with order > 11 (the default MAX_ORDER of Linux buddy allocator). Such over size allocation will fail, and cause 2 problems, - When CONFIG_BCACHE_DEBUG is configured, bch_btree_verify() does not work, because c->verify_ondisk is NULL and bch_btree_verify() returns immediately. - bch_btree_cache_alloc() will fail due to c->verify_ondisk allocation failed, then the whole cache device registration fails. And because of this failure, the first problem of bch_btree_verify() has no chance to be triggered. This patch fixes the above problem by two means, 1) If pages allocation of c->verify_ondisk fails, set it to NULL and returns bch_btree_cache_alloc() with -ENOMEM. 2) When calling __get_free_pages() to allocate c->verify_ondisk pages, use ilog2(meta_bucket_pages(&c->sb)) to make sure ilog2() will always generate a pages order <= MAX_ORDER (or CONFIG_FORCE_MAX_ZONEORDER). Then the buddy system won't directly reject the allocation request. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-25bcache: allocate meta data pages as compound pagesColy Li
There are some meta data of bcache are allocated by multiple pages, and they are used as bio bv_page for I/Os to the cache device. for example cache_set->uuids, cache->disk_buckets, journal_write->data, bset_tree->data. For such meta data memory, all the allocated pages should be treated as a single memory block. Then the memory management and underlying I/O code can treat them more clearly. This patch adds __GFP_COMP flag to all the location allocating >0 order pages for the above mentioned meta data. Then their pages are treated as compound pages now. Signed-off-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01block: rename generic_make_request to submit_bio_noacctChristoph Hellwig
generic_make_request has always been very confusingly misnamed, so rename it to submit_bio_noacct to make it clear that it is submit_bio minus accounting and a few checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-14bcache: fix potential deadlock problem in btree_gc_coalesceZhiqiang Liu
coccicheck reports: drivers/md//bcache/btree.c:1538:1-7: preceding lock on line 1417 In btree_gc_coalesce func, if the coalescing process fails, we will goto to out_nocoalesce tag directly without releasing new_nodes[i]->write_lock. Then, it will cause a deadlock when trying to acquire new_nodes[i]-> write_lock for freeing new_nodes[i] before return. btree_gc_coalesce func details as follows: if alloc new_nodes[i] fails: goto out_nocoalesce; // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock) // main coalescing process for (i = nodes - 1; i > 0; --i) [snipped] if coalescing process fails: // Here, directly goto out_nocoalesce // tag will cause a deadlock goto out_nocoalesce; [snipped] // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock) // coalesing succ, return return; out_nocoalesce: btree_node_free(new_nodes[i]) // free new_nodes[i] // obtain new_nodes[i]->write_lock mutex_lock(&new_nodes[i]->write_lock); // set flag for reuse clear_bit(BTREE_NODE_dirty, &ew_nodes[i]->flags); // release new_nodes[i]->write_lock mutex_unlock(&new_nodes[i]->write_lock); To fix the problem, we add a new tag 'out_unlock_nocoalesce' for releasing new_nodes[i]->write_lock before out_nocoalesce tag. If coalescing process fails, we will go to out_unlock_nocoalesce tag for releasing new_nodes[i]->write_lock before free new_nodes[i] in out_nocoalesce tag. (Coly Li helps to clean up commit log format.) Fixes: 2a285686c109816 ("bcache: btree locking rework") Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27bcache: Convert pr_<level> uses to a more typical styleJoe Perches
Remove the trailing newline from the define of pr_fmt and add newlines to the uses. Miscellanea: o Convert bch_bkey_dump from multiple uses of pr_err to pr_cont as the earlier conversion was inappropriate done causing multiple lines to be emitted where only a single output line was desired o Use vsprintf extension %pV in bch_cache_set_error to avoid multiple line output where only a single line output was desired o Coalesce formats Fixes: 6ae63e3501c4 ("bcache: replace printk() by pr_*() routines") Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27bcache: remove redundant variables i and nColin Ian King
Variables i and n are being assigned but are never used. They are redundant and can be removed. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Coly Li <colyli@suse.de> Addresses-Coverity: ("Unused value") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22bcache: optimize barrier usage for atomic operationsColy Li
The idea of this patch is from Davidlohr Bueso, he posts a patch for bcache to optimize barrier usage for read-modify-write atomic bitops. Indeed such optimization can also apply on other locations where smp_mb() is used before or after an atomic operation. This patch replaces smp_mb() with smp_mb__before_atomic() or smp_mb__after_atomic() in btree.c and writeback.c, where it is used to synchronize memory cache just earlier on other cores. Although the locations are not on hot code path, it is always not bad to mkae things a little better. Signed-off-by: Coly Li <colyli@suse.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22bcache: make bch_btree_check() to be multithreadedColy Li
When registering a cache device, bch_btree_check() is called to check all btree nodes, to make sure the btree is consistent and not corrupted. bch_btree_check() is recursively executed in a single thread, when there are a lot of data cached and the btree is huge, it may take very long time to check all the btree nodes. In my testing, I observed it took around 50 minutes to finish bch_btree_check(). When checking the bcache btree nodes, the cache set is not running yet, and indeed the whole tree is in read-only state, it is safe to create multiple threads to check the btree in parallel. This patch tries to create multiple threads, and each thread tries to one-by-one check the sub-tree indexed by a key from the btree root node. The parallel thread number depends on how many keys in the btree root node. At most BCH_BTR_CHKTHREAD_MAX (64) threads can be created, but in practice is should be min(cpu-number/2, root-node-keys-number). Signed-off-by: Coly Li <colyli@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22bcache: add bcache_ prefix to btree_root() and btree() macrosColy Li
This patch changes macro btree_root() and btree() to bcache_btree_root() and bcache_btree(), to avoid potential generic name clash in future. NOTE: for product kernel maintainers, this patch can be skipped if you feel the rename stuffs introduce inconvenince to patch backport. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22bcache: move macro btree() and btree_root() into btree.hColy Li
In order to accelerate bcache registration speed, the macro btree() and btree_root() will be referenced out of btree.c. This patch moves them from btree.c into btree.h with other relative function declaration in btree.h, for the following changes. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02Revert "bcache: ignore pending signals when creating gc and allocator thread"Jens Axboe
This reverts commit 0b96da639a4874311e9b5156405f69ef9fc3bef8. We can't just go flushing random signals, under the assumption that the OOM killer will just do something else. It's not safe from the OOM perspective, and it could also cause other signals to get randomly lost. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-13bcache: ignore pending signals when creating gc and allocator threadColy Li
When run a cache set, all the bcache btree node of this cache set will be checked by bch_btree_check(). If the bcache btree is very large, iterating all the btree nodes will occupy too much system memory and the bcache registering process might be selected and killed by system OOM killer. kthread_run() will fail if current process has pending signal, therefore the kthread creating in run_cache_set() for gc and allocator kernel threads are very probably failed for a very large bcache btree. Indeed such OOM is safe and the registering process will exit after the registration done. Therefore this patch flushes pending signals during the cache set start up, specificly in bch_cache_allocator_start() and bch_gc_thread_start(), to make sure run_cache_set() won't fail for large cahced data set. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-23bcache: reap from tail of c->btree_cache in bch_mca_scan()Coly Li
When shrink btree node cache from c->btree_cache in bch_mca_scan(), no matter the selected node is reaped or not, it will be rotated from the head to the tail of c->btree_cache list. But in bcache journal code, when flushing the btree nodes with oldest journal entry, btree nodes are iterated and slected from the tail of c->btree_cache list in btree_flush_write(). The list_rotate_left() in bch_mca_scan() will make btree_flush_write() iterate more nodes in c->btree_list in reverse order. This patch just reaps the selected btree node cache, and not move it from the head to the tail of c->btree_cache list. Then bch_mca_scan() will not mess up c->btree_cache list to btree_flush_write(). Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-23bcache: reap c->btree_cache_freeable from the tail in bch_mca_scan()Coly Li
In order to skip the most recently freed btree node cahce, currently in bch_mca_scan() the first 3 caches in c->btree_cache_freeable list are skipped when shrinking bcache node caches in bch_mca_scan(). The related code in bch_mca_scan() is, 737 list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) { 738 if (nr <= 0) 739 goto out; 740 741 if (++i > 3 && 742 !mca_reap(b, 0, false)) { lines free cache memory 746 } 747 nr--; 748 } The problem is, if virtual memory code calls bch_mca_scan() and the calculated 'nr' is 1 or 2, then in the above loop, nothing will be shunk. In such case, if slub/slab manager calls bch_mca_scan() for many times with small scan number, it does not help to shrink cache memory and just wasts CPU cycles. This patch just selects btree node caches from tail of the c->btree_cache_freeable list, then the newly freed host cache can still be allocated by mca_alloc(), and at least 1 node can be shunk. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-23bcache: remove member accessed from struct btreeColy Li
The member 'accessed' of struct btree is used in bch_mca_scan() when shrinking btree node caches. The original idea is, if b->accessed is set, clean it and look at next btree node cache from c->btree_cache list, and only shrink the caches whose b->accessed is cleaned. Then only cold btree node cache will be shrunk. But when I/O pressure is high, it is very probably that b->accessed of a btree node cache will be set again in bch_btree_node_get() before bch_mca_scan() selects it again. Then there is no chance for bch_mca_scan() to shrink enough memory back to slub or slab system. This patch removes member accessed from struct btree, then once a btree node ache is selected, it will be immediately shunk. By this change, bch_mca_scan() may release btree node cahce more efficiently. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-18Revert "bcache: fix fifo index swapping condition in journal_pin_cmp()"Jens Axboe
Coly says: "Guoju Fang talked to me today, he told me this change was unnecessary and I was over-thought. Then I realize fifo_idx() uses a mask to handle the array index overflow condition, so the index swap in journal_pin_cmp() won't happen. And yes, Guoju and Kent are correct. Since you already applied this patch, can you please to remove this patch from your for-next branch? This single patch does not break thing, but it is unecessary at this moment." This reverts commit c0e0954e909c17b43d176ab219fc598964616ae6. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13bcache: at least try to shrink 1 node in bch_mca_scan()Coly Li
In bch_mca_scan(), the number of shrinking btree node is calculated by code like this, unsigned long nr = sc->nr_to_scan; nr /= c->btree_pages; nr = min_t(unsigned long, nr, mca_can_free(c)); variable sc->nr_to_scan is number of objects (here is bcache B+tree nodes' number) to shrink, and pointer variable sc is sent from memory management code as parametr of a callback. If sc->nr_to_scan is smaller than c->btree_pages, after the above calculation, variable 'nr' will be 0 and nothing will be shrunk. It is frequeently observed that only 1 or 2 is set to sc->nr_to_scan and make nr to be zero. Then bch_mca_scan() will do nothing more then acquiring and releasing mutex c->bucket_lock. This patch checkes whether nr is 0 after the above calculation, if 0 is the result then set 1 to variable 'n'. Then at least bch_mca_scan() will try to shrink a single B+tree node. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13bcache: add code comments in bch_btree_leaf_dirty()Coly Li
This patch adds code comments in bch_btree_leaf_dirty() to explain why w->journal should always reference the eldest journal pin of all the writing bkeys in the btree node. To make the bcache journal code to be easier to be understood. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-13bcache: fix a lost wake-up problem caused by mca_cannibalize_lockGuoju Fang
This patch fix a lost wake-up problem caused by the race between mca_cannibalize_lock and bch_cannibalize_unlock. Consider two processes, A and B. Process A is executing mca_cannibalize_lock, while process B takes c->btree_cache_alloc_lock and is executing bch_cannibalize_unlock. The problem happens that after process A executes cmpxchg and will execute prepare_to_wait. In this timeslice process B executes wake_up, but after that process A executes prepare_to_wait and set the state to TASK_INTERRUPTIBLE. Then process A goes to sleep but no one will wake up it. This problem may cause bcache device to dead. Signed-off-by: Guoju Fang <fangguoju@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>