user/sven/linux.git/include/linux/swap.h, branch v4.4.275

include/linux/swap.h: use offsetof() instead of custom __swapoffset macro

2019-04-27T07:33:59Z

[ Upstream commit a4046c06be50a4f01d435aa7fe57514818e6cc82 ] Use offsetof() to calculate offset of a field to take advantage of compiler built-in version when possible, and avoid UBSAN warning when compiling with Clang: UBSAN: Undefined behaviour in mm/swapfile.c:3010:38 member access within null pointer of type 'union swap_header' CPU: 6 PID: 1833 Comm: swapon Tainted: G S 4.19.23 #43 Call trace: dump_backtrace+0x0/0x194 show_stack+0x20/0x2c __dump_stack+0x20/0x28 dump_stack+0x70/0x94 ubsan_epilogue+0x14/0x44 ubsan_type_mismatch_common+0xf4/0xfc __ubsan_handle_type_mismatch_v1+0x34/0x54 __se_sys_swapon+0x654/0x1084 __arm64_sys_swapon+0x1c/0x24 el0_svc_common+0xa8/0x150 el0_svc_compat_handler+0x2c/0x38 el0_svc_compat+0x8/0x18 Link: http://lkml.kernel.org/r/20190312081902.223764-1-pihsun@chromium.org Signed-off-by: Pi-Hsun Shih Acked-by: Michal Hocko Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

Using BUG_ON() as an assert() is _never_ acceptable

2016-10-28T07:01:34Z

commit 21f54ddae449f4bdd9f1498124901d67202243d9 upstream. That just generally kills the machine, and makes debugging only much harder, since the traces may long be gone. Debugging by assert() is a disease. Don't do it. If you can continue, you're much better off doing so with a live machine where you have a much higher chance that the report actually makes it to the system logs, rather than result in a machine that is just completely dead. The only valid situation for BUG_ON() is when continuing is not an option, because there is massive corruption. But if you are just verifying that something is true, you warn about your broken assumptions (preferably just once), and limp on. Fixes: 22f2ac51b6d6 ("mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()") Cc: Johannes Weiner Cc: Miklos Szeredi Cc: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Michal Hocko Signed-off-by: Greg Kroah-Hartman

mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()

2016-10-28T07:01:34Z

commit 22f2ac51b6d643666f4db093f13144f773ff3f3a upstream. Antonio reports the following crash when using fuse under memory pressure: kernel BUG at /build/linux-a2WvEb/linux-4.4.0/mm/workingset.c:346! invalid opcode: 0000 [#1] SMP Modules linked in: all of them CPU: 2 PID: 63 Comm: kswapd0 Not tainted 4.4.0-36-generic #55-Ubuntu Hardware name: System manufacturer System Product Name/P8H67-M PRO, BIOS 3904 04/27/2013 task: ffff88040cae6040 ti: ffff880407488000 task.ti: ffff880407488000 RIP: shadow_lru_isolate+0x181/0x190 Call Trace: __list_lru_walk_one.isra.3+0x8f/0x130 list_lru_walk_one+0x23/0x30 scan_shadow_nodes+0x34/0x50 shrink_slab.part.40+0x1ed/0x3d0 shrink_zone+0x2ca/0x2e0 kswapd+0x51e/0x990 kthread+0xd8/0xf0 ret_from_fork+0x3f/0x70 which corresponds to the following sanity check in the shadow node tracking: BUG_ON(node->count & RADIX_TREE_COUNT_MASK); The workingset code tracks radix tree nodes that exclusively contain shadow entries of evicted pages in them, and this (somewhat obscure) line checks whether there are real pages left that would interfere with reclaim of the radix tree node under memory pressure. While discussing ways how fuse might sneak pages into the radix tree past the workingset code, Miklos pointed to replace_page_cache_page(), and indeed there is a problem there: it properly accounts for the old page being removed - __delete_from_page_cache() does that - but then does a raw raw radix_tree_insert(), not accounting for the replacement page. Eventually the page count bits in node->count underflow while leaving the node incorrectly linked to the shadow node LRU. To address this, make sure replace_page_cache_page() uses the tracked page insertion code, page_cache_tree_insert(). This fixes the page accounting and makes sure page-containing nodes are properly unlinked from the shadow node LRU again. Also, make the sanity checks a bit less obscure by using the helpers for checking the number of pages and shadows in a radix tree node. [mhocko@suse.com: backport for 4.4] Fixes: 449dd6984d0e ("mm: keep page cache radix tree nodes in check") Link: http://lkml.kernel.org/r/20160919155822.29498-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: Antonio SJ Musumeci Debugged-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Michal Hocko Signed-off-by: Greg Kroah-Hartman

mm: swap: zswap: maybe_preload & refactoring

2015-09-08T22:35:28Z

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 Cc: Vladimir Davydov Cc: Michal Hocko Cc: Hugh Dickins Cc: Minchan Kim Cc: Tejun Heo Cc: Jens Axboe Cc: Christoph Hellwig Cc: David Herrmann Cc: Seth Jennings Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: export struct mem_cgroup

2015-09-08T22:35:28Z

mem_cgroup structure is defined in mm/memcontrol.c currently which means that the code outside of this file has to use external API even for trivial access stuff. This patch exports mm_struct with its dependencies and makes some of the exported functions inlines. This even helps to reduce the code size a bit (make defconfig + CONFIG_MEMCG=y) text data bss dec hex filename 12355346 1823792 1089536 15268674 e8fb42 vmlinux.before 12354970 1823792 1089536 15268298 e8f9ca vmlinux.after This is not much (370B) but better than nothing. We also save a function call in some hot paths like callers of mem_cgroup_count_vm_event which is used for accounting. The patch doesn't introduce any functional changes. [vdavykov@parallels.com: inline memcg_kmem_is_active] [vdavykov@parallels.com: do not expose type outside of CONFIG_MEMCG] [akpm@linux-foundation.org: memcontrol.h needs eventfd.h for eventfd_ctx] [akpm@linux-foundation.org: export mem_cgroup_from_task() to modules] Signed-off-by: Michal Hocko Reviewed-by: Vladimir Davydov Suggested-by: Johannes Weiner Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: /proc/pid/smaps:: show proportional swap share of the mapping

2015-09-08T22:35:28Z

We want to know per-process workingset size for smart memory management on userland and we use swap(ex, zram) heavily to maximize memory efficiency so workingset includes swap as well as RSS. On such system, if there are lots of shared anonymous pages, it's really hard to figure out exactly how many each process consumes memory(ie, rss + wap) if the system has lots of shared anonymous memory(e.g, android). This patch introduces SwapPss field on /proc//smaps so we can get more exact workingset size per process. Bongkyu tested it. Result is below. 1. 50M used swap SwapTotal: 461976 kB SwapFree: 411192 kB $ adb shell cat /proc/*/smaps | grep "SwapPss:" | awk '{sum += $2} END {print sum}'; 48236 $ adb shell cat /proc/*/smaps | grep "Swap:" | awk '{sum += $2} END {print sum}'; 141184 2. 240M used swap SwapTotal: 461976 kB SwapFree: 216808 kB $ adb shell cat /proc/*/smaps | grep "SwapPss:" | awk '{sum += $2} END {print sum}'; 230315 $ adb shell cat /proc/*/smaps | grep "Swap:" | awk '{sum += $2} END {print sum}'; 1387744 [akpm@linux-foundation.org: simplify kunmap_atomic() call] Signed-off-by: Minchan Kim Reported-by: Bongkyu Kim Tested-by: Bongkyu Kim Cc: Hugh Dickins Cc: Sergey Senozhatsky Cc: Jonathan Corbet Cc: Jerome Marchand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block: add a bi_error field to struct bio

2015-07-29T14:55:15Z

Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: NeilBrown Signed-off-by: Jens Axboe

suspend: simplify block I/O handling

2015-05-19T15:19:59Z

Stop abusing struct page functionality and the swap end_io handler, and instead add a modified version of the blk-lib.c bio_batch helpers. Also move the block I/O code into swap.c as they are directly tied into each other. Signed-off-by: Christoph Hellwig Tested-by: Pavel Machek Tested-by: Ming Lin Acked-by: Pavel Machek Acked-by: Rafael J. Wysocki Signed-off-by: Jens Axboe

mm: rename deactivate_page to deactivate_file_page

2015-04-15T23:35:17Z

"deactivate_page" was created for file invalidation so it has too specific logic for file-backed pages. So, let's change the name of the function and date to a file-specific one and yield the generic name. Signed-off-by: Minchan Kim Cc: Michal Hocko Cc: Johannes Weiner Cc: Mel Gorman Cc: Rik van Riel Cc: Shaohua Li Cc: Wang, Yalin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

swap: remove unused mem_cgroup_uncharge_swapcache declaration

2015-02-12T01:06:00Z

The body of this function was removed by commit 0a31bc97c80c ("mm: memcontrol: rewrite uncharge API"). Signed-off-by: Vladimir Davydov Acked-by: Michal Hocko Acked-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds