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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2015-02-27 13:13:14 +0100
committerJaegeuk Kim <jaegeuk@kernel.org>2015-04-11 00:08:30 +0200
commit7ecebe5e07958a0b7e54a560dbc24144287c6b41 (patch)
tree80dea6f9cbf6586ee51ecf55694fd47c2dc1e1a3 /fs/f2fs
parentf2fs: fix max orphan inodes calculation (diff)
downloadlinux-7ecebe5e07958a0b7e54a560dbc24144287c6b41.tar.xz
linux-7ecebe5e07958a0b7e54a560dbc24144287c6b41.zip
f2fs: add cond_resched() to sync_dirty_dir_inodes()
In a preempt-off enviroment a alot of FS activity (write/delete) I run into a CPU stall: | NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u2:2:59] | Modules linked in: | CPU: 0 PID: 59 Comm: kworker/u2:2 Tainted: G W 3.19.0-00010-g10c11c51ffed #153 | Workqueue: writeback bdi_writeback_workfn (flush-179:0) | task: df230000 ti: df23e000 task.ti: df23e000 | PC is at __submit_merged_bio+0x6c/0x110 | LR is at f2fs_submit_merged_bio+0x74/0x80 … | [<c00085c4>] (gic_handle_irq) from [<c0012e84>] (__irq_svc+0x44/0x5c) | Exception stack(0xdf23fb48 to 0xdf23fb90) | fb40: deef3484 ffff0001 ffff0001 00000027 deef3484 00000000 | fb60: deef3440 00000000 de426000 deef34ec deefc440 df23fbb4 df23fbb8 df23fb90 | fb80: c02191f0 c0218fa0 60000013 ffffffff | [<c0012e84>] (__irq_svc) from [<c0218fa0>] (__submit_merged_bio+0x6c/0x110) | [<c0218fa0>] (__submit_merged_bio) from [<c02191f0>] (f2fs_submit_merged_bio+0x74/0x80) | [<c02191f0>] (f2fs_submit_merged_bio) from [<c021624c>] (sync_dirty_dir_inodes+0x70/0x78) | [<c021624c>] (sync_dirty_dir_inodes) from [<c0216358>] (write_checkpoint+0x104/0xc10) | [<c0216358>] (write_checkpoint) from [<c021231c>] (f2fs_sync_fs+0x80/0xbc) | [<c021231c>] (f2fs_sync_fs) from [<c0221eb8>] (f2fs_balance_fs_bg+0x4c/0x68) | [<c0221eb8>] (f2fs_balance_fs_bg) from [<c021e9b8>] (f2fs_write_node_pages+0x40/0x110) | [<c021e9b8>] (f2fs_write_node_pages) from [<c00de620>] (do_writepages+0x34/0x48) | [<c00de620>] (do_writepages) from [<c0145714>] (__writeback_single_inode+0x50/0x228) | [<c0145714>] (__writeback_single_inode) from [<c0146184>] (writeback_sb_inodes+0x1a8/0x378) | [<c0146184>] (writeback_sb_inodes) from [<c01463e4>] (__writeback_inodes_wb+0x90/0xc8) | [<c01463e4>] (__writeback_inodes_wb) from [<c01465f8>] (wb_writeback+0x1dc/0x28c) | [<c01465f8>] (wb_writeback) from [<c0146dd8>] (bdi_writeback_workfn+0x2ac/0x460) | [<c0146dd8>] (bdi_writeback_workfn) from [<c003c3fc>] (process_one_work+0x11c/0x3a4) | [<c003c3fc>] (process_one_work) from [<c003c844>] (worker_thread+0x17c/0x490) | [<c003c844>] (worker_thread) from [<c0041398>] (kthread+0xec/0x100) | [<c0041398>] (kthread) from [<c000ed10>] (ret_from_fork+0x14/0x24) As it turns out, the code loops in sync_dirty_dir_inodes() and waits for others to make progress but since it never leaves the CPU there is no progress made. At the time of this stall, there is also a rm process blocked: | rm R running 0 1989 1774 0x00000000 | [<c047c55c>] (__schedule) from [<c00486dc>] (__cond_resched+0x30/0x4c) | [<c00486dc>] (__cond_resched) from [<c047c8c8>] (_cond_resched+0x4c/0x54) | [<c047c8c8>] (_cond_resched) from [<c00e1aec>] (truncate_inode_pages_range+0x1f0/0x5e8) | [<c00e1aec>] (truncate_inode_pages_range) from [<c00e1fd8>] (truncate_inode_pages+0x28/0x30) | [<c00e1fd8>] (truncate_inode_pages) from [<c00e2148>] (truncate_inode_pages_final+0x60/0x64) | [<c00e2148>] (truncate_inode_pages_final) from [<c020c92c>] (f2fs_evict_inode+0x4c/0x268) | [<c020c92c>] (f2fs_evict_inode) from [<c0137214>] (evict+0x94/0x140) | [<c0137214>] (evict) from [<c01377e8>] (iput+0xc8/0x134) | [<c01377e8>] (iput) from [<c01333e4>] (d_delete+0x154/0x180) | [<c01333e4>] (d_delete) from [<c0129870>] (vfs_rmdir+0x114/0x12c) | [<c0129870>] (vfs_rmdir) from [<c012d644>] (do_rmdir+0x158/0x168) | [<c012d644>] (do_rmdir) from [<c012dd90>] (SyS_unlinkat+0x30/0x3c) | [<c012dd90>] (SyS_unlinkat) from [<c000ec40>] (ret_fast_syscall+0x0/0x4c) As explained by Jaegeuk Kim: |This inode is the directory (c.f., do_rmdir) causing a infinite loop on |sync_dirty_dir_inodes. |The sync_dirty_dir_inodes tries to flush dirty dentry pages, but if the |inode is under eviction, it submits bios and do it again until eviction |is finished. This patch adds a cond_resched() (as suggested by Jaegeuk) after a BIO is submitted so other thread can make progress. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [Jaegeuk Kim: change fs/f2fs to f2fs in subject as naming convention] Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/checkpoint.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 81d6d2f0e8ed..53bc32804841 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -795,6 +795,7 @@ retry:
* wribacking dentry pages in the freeing inode.
*/
f2fs_submit_merged_bio(sbi, DATA, WRITE);
+ cond_resched();
}
goto retry;
}