kernel.git/drivers/md/dm-bufio.c, branch linux-5.6.y

dm bufio: introduce a global cache replacement

2019-09-13T21:00:21Z

This commit introduces a global cache replacement (instead of per-client cleanup). If one bufio client uses the cache heavily and another client is not using it, we want to let the first client use most of the cache. The old algorithm would partition the cache equally betwen the clients and that is sub-optimal. For cache replacement, we use the clock algorithm because it doesn't require taking any lock when the buffer is accessed. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: remove old-style buffer cleanup

2019-09-13T14:43:48Z

Remove code that cleans up buffers if the cache size grows over the limit. The next commit will introduce a new global cleanup. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: introduce a global queue

2019-09-13T14:43:27Z

Rename param_spinlock to global_spinlock and introduce a global queue of all used buffers. The queue will be used in the following commits. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: refactor adjust_total_allocated

2019-09-13T14:43:07Z

Refactor adjust_total_allocated() so that it takes a bool argument indicating if it should add or subtract the buffer size. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: call adjust_total_allocated from __link_buffer and __unlink_buffer

2019-09-13T14:42:27Z

Move the call to adjust_total_allocated() to __link_buffer() and __unlink_buffer() so that only used buffers are counted. Reserved buffers are not. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

Revert "dm bufio: fix deadlock with loop device"

2019-08-15T19:57:39Z

Revert the commit bd293d071ffe65e645b4d8104f9d8fe15ea13862. The proper fix has been made available with commit d0a255e795ab ("loop: set PF_MEMALLOC_NOIO for the worker thread"). Note that the fix offered by commit bd293d071ffe doesn't really prevent the deadlock from occuring - if we look at the stacktrace reported by Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex - i.e. it has already successfully taken the mutex. Changing the mutex from mutex_lock to mutex_trylock won't help with deadlocks that happen afterwards. PID: 474 TASK: ffff8813e11f4600 CPU: 10 COMMAND: "kswapd0" #0 [ffff8813dedfb938] __schedule at ffffffff8173f405 #1 [ffff8813dedfb990] schedule at ffffffff8173fa27 #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186 #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8 #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81 #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio] #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio] #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio] #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778 #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f #13 [ffff8813dedfbec0] kthread at ffffffff810a8428 #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242 Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Fixes: bd293d071ffe ("dm bufio: fix deadlock with loop device") Depends-on: d0a255e795ab ("loop: set PF_MEMALLOC_NOIO for the worker thread") Signed-off-by: Mike Snitzer

dm bufio: fix deadlock with loop device

2019-07-12T13:59:37Z

When thin-volume is built on loop device, if available memory is low, the following deadlock can be triggered: One process P1 allocates memory with GFP_FS flag, direct alloc fails, memory reclaim invokes memory shrinker in dm_bufio, dm_bufio_shrink_scan() runs, mutex dm_bufio_client->lock is acquired, then P1 waits for dm_buffer IO to complete in __try_evict_buffer(). But this IO may never complete if issued to an underlying loop device that forwards it using direct-IO, which allocates memory using GFP_KERNEL (see: do_blockdev_direct_IO()). If allocation fails, memory reclaim will invoke memory shrinker in dm_bufio, dm_bufio_shrink_scan() will be invoked, and since the mutex is already held by P1 the loop thread will hang, and IO will never complete. Resulting in ABBA deadlock. Cc: stable@vger.kernel.org Signed-off-by: Junxiao Bi Signed-off-by: Mike Snitzer

dm bufio: Simplify stack trace retrieval

2019-04-29T10:37:52Z

Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Steven Rostedt Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.446326191@linutronix.de

Merge branch 'akpm' (patches from Andrew)

2018-12-29T00:55:46Z

Merge misc updates from Andrew Morton: - large KASAN update to use arm's "software tag-based mode" - a few misc things - sh updates - ocfs2 updates - just about all of MM * emailed patches from Andrew Morton : (167 commits) kernel/fork.c: mark 'stack_vm_area' with __maybe_unused memcg, oom: notify on oom killer invocation from the charge path mm, swap: fix swapoff with KSM pages include/linux/gfp.h: fix typo mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization memory_hotplug: add missing newlines to debugging output mm: remove __hugepage_set_anon_rmap() include/linux/vmstat.h: remove unused page state adjustment macro mm/page_alloc.c: allow error injection mm: migrate: drop unused argument of migrate_page_move_mapping() blkdev: avoid migration stalls for blkdev pages mm: migrate: provide buffer_migrate_page_norefs() mm: migrate: move migrate_page_lock_buffers() mm: migrate: lock buffers before migrate_page_move_mapping() mm: migration: factor out code to compute expected number of page references mm, page_alloc: enable pcpu_drain with zone capability kmemleak: add config to select auto scan mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init ...

mm: convert totalram_pages and totalhigh_pages variables to atomic

2018-12-28T20:11:47Z

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 Suggested-by: Michal Hocko Suggested-by: Vlastimil Babka Reviewed-by: Konstantin Khlebnikov Reviewed-by: Pavel Tatashin Acked-by: Michal Hocko Acked-by: Vlastimil Babka Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds