/* * common eBPF ELF operations. * * Copyright (C) 2013-2015 Alexei Starovoitov * Copyright (C) 2015 Wang Nan * Copyright (C) 2015 Huawei Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; * version 2.1 of the License (not later!) * * 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, see */ #ifndef __BPF_BPF_H #define __BPF_BPF_H #include int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size, int max_entries, __u32 map_flags); /* Recommend log buffer size */ #define BPF_LOG_BUF_SIZE 65536 int bpf_load_program(enum bpf_prog_type type, struct bpf_insn *insns, size_t insns_cnt, char *license, __u32 kern_version, char *log_buf, size_t log_buf_sz); int bpf_map_update_elem(int fd, void *key, void *value, __u64 flags); int bpf_map_lookup_elem(int fd, void *key, void *value); int bpf_map_delete_elem(int fd, void *key); int bpf_map_get_next_key(int fd, void *key, void *next_key); int bpf_obj_pin(int fd, const char *pathname); int bpf_obj_get(const char *pathname); int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type); int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type); #endif it/tree/?id=d1908f52557b3230fbd63c0429f3b4b748bf2b6d'>treecommitdiff
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authorMichal Hocko <mhocko@suse.com>2017-02-03 13:13:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-03 14:13:19 -0800
commitd1908f52557b3230fbd63c0429f3b4b748bf2b6d (patch)
tree6789f8adc26e2394285be937d3480c58de92cc6b
parenta96dfddbcc04336bbed50dc2b24823e45e09e80c (diff)
fs: break out of iomap_file_buffered_write on fatal signals
Tetsuo has noticed that an OOM stress test which performs large write requests can cause the full memory reserves depletion. He has tracked this down to the following path __alloc_pages_nodemask+0x436/0x4d0 alloc_pages_current+0x97/0x1b0 __page_cache_alloc+0x15d/0x1a0 mm/filemap.c:728 pagecache_get_page+0x5a/0x2b0 mm/filemap.c:1331 grab_cache_page_write_begin+0x23/0x40 mm/filemap.c:2773 iomap_write_begin+0x50/0xd0 fs/iomap.c:118 iomap_write_actor+0xb5/0x1a0 fs/iomap.c:190 ? iomap_write_end+0x80/0x80 fs/iomap.c:150 iomap_apply+0xb3/0x130 fs/iomap.c:79 iomap_file_buffered_write+0x68/0xa0 fs/iomap.c:243 ? iomap_write_end+0x80/0x80 xfs_file_buffered_aio_write+0x132/0x390 [xfs] ? remove_wait_queue+0x59/0x60 xfs_file_write_iter+0x90/0x130 [xfs] __vfs_write+0xe5/0x140 vfs_write+0xc7/0x1f0 ? syscall_trace_enter+0x1d0/0x380 SyS_write+0x58/0xc0 do_syscall_64+0x6c/0x200 entry_SYSCALL64_slow_path+0x25/0x25 the oom victim has access to all memory reserves to make a forward progress to exit easier. But iomap_file_buffered_write and other callers of iomap_apply loop to complete the full request. We need to check for fatal signals and back off with a short write instead. As the iomap_apply delegates all the work down to the actor we have to hook into those. All callers that work with the page cache are calling iomap_write_begin so we will check for signals there. dax_iomap_actor has to handle the situation explicitly because it copies data to the userspace directly. Other callers like iomap_page_mkwrite work on a single page or iomap_fiemap_actor do not allocate memory based on the given len. Fixes: 68a9f5e7007c ("xfs: implement iomap based buffered write path") Link: http://lkml.kernel.org/r/20170201092706.9966-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat
-rw-r--r--fs/dax.c5
-rw-r--r--fs/iomap.c3
2 files changed, 8 insertions, 0 deletions
diff --git a/fs/dax.c b/fs/dax.c