| Message ID | 1458651208-25940-1-git-send-email-kernel@kyup.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/fs/dcache.c b/fs/dcache.c index 2398f9f94337..0db355a50bc5 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -934,6 +934,9 @@ static void shrink_dentry_list(struct list_head *list) while (!list_empty(list)) { struct inode *inode; + + cond_resched(); + dentry = list_entry(list->prev, struct dentry, d_lru); spin_lock(&dentry->d_lock); parent = lock_parent(dentry);
A softlockup in shrink_dentry_list when called from shrink_dcache_sb was observed on a very busy server. It's possible that the list passed to shrink_dentry_list is so big that it takes a while to dispose of all entries. Adding a simple cond_resched would give the cpu a chance to do some other useful work and no trip the softlockup watchdog. Signed-off-by: Nikolay Borisov <kernel@kyup.com> --- Here is what the splat looked like. Even though this was observed on a 3.12 kernel I don't see why it can't happen on recent kernels as well. [1294411.570734] BUG: soft lockup - CPU#3 stuck for 22s! [mount:33726] [1294411.571005] Modules linked in: xt_comment ipip tunnel4 ip6_tunnel tunnel6 tcp_diag inet_diag xt_time act_police cls_basic sch_ingress hijack(O) netconsole xt_multiport xt_pkttype ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state veth openvswitch gre vxlan ip_tunnel xt_owner xt_conntrack iptable_mangle xt_nat iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat xt_CT nf_conntrack iptable_raw ip6table_filter ip6_tables ipv6 ext2 dm_thin_pool dm_bio_prison dm_persistent_data dm_bufio dm_mirror dm_region_hash dm_log ib_ipoib ib_cm ib_sa ib_mad ib_core ixgbe i2c_i801 lpc_ich mfd_core ioapic ioatdma igb dca i2c_algo_bit [last unloaded: ipmi_msghandler] [1294411.571047] CPU: 3 PID: 33726 Comm: mount Tainted: G O 3.12.52-clouder2 #1 [1294411.571048] Hardware name: Supermicro X9DRD-7LN4F(-JBOD)/X9DRD-EF/X9DRD-7LN4F, BIOS 3.0a 12/05/2013 [1294411.571050] task: ffff8833c55f9830 ti: ffff883fcfcf6000 task.ti: ffff883fcfcf6000 [1294411.571051] RIP: 0010:[<ffffffff811c2bc0>] [<ffffffff811c2bc0>] __d_drop+0x60/0xf0 [1294411.571056] RSP: 0018:ffff883fcfcf7d38 EFLAGS: 00000206 [1294411.571057] RAX: ffffc9000b101770 RBX: ffff881fff8cc6a0 RCX: 0000000000000007 [1294411.571058] RDX: ffff883fcfcf6000 RSI: 0000000000000000 RDI: ffff8805bd5063c0 [1294411.571058] RBP: ffff883fcfcf7d38 R08: 0000000000000073 R09: 0000000000000000 [1294411.571059] R10: 7fffffffffffffff R11: 0000000000000000 R12: ffff8805bd506530 [1294411.571060] R13: ffff883fcfcf7cc8 R14: 0000000000000000 R15: ffff881fff8cc6a0 [1294411.571061] FS: 00007f0321cca7e0(0000) GS:ffff881fff8c0000(0000) knlGS:0000000000000000 [1294411.571062] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1294411.571063] CR2: 00007f0320d7e0c0 CR3: 0000001e050f6000 CR4: 00000000001407e0 [1294411.571063] Stack: [1294411.571064] ffff883fcfcf7d68 ffffffff811c3372 0000000000000202 ffff8805bd5063c0 [1294411.571068] ffff8805bd506440 ffff881fd0c9ec00 ffff883fcfcf7dd8 ffffffff811c36e6 [1294411.571070] 0000000000000001 ffff883fcfcf7df8 ffff883fcfcf6000 ffff883fcfcf6000 [1294411.571073] Call Trace: [1294411.571078] [<ffffffff811c3372>] __dentry_kill+0x62/0x210 [1294411.571080] [<ffffffff811c36e6>] shrink_dentry_list+0x1c6/0x390 [1294411.571082] [<ffffffff811c3bcb>] shrink_dcache_sb+0xcb/0x110 [1294411.571086] [<ffffffff811ad42a>] do_remount_sb+0x4a/0x190 [1294411.571089] [<ffffffff811ce200>] do_mount+0xaf0/0xd20 [1294411.571091] [<ffffffff811ce4c7>] SyS_mount+0x97/0xf0 [1294411.571095] [<ffffffff8164c4b2>] system_call_fastpath+0x16/0x1b fs/dcache.c | 3 +++ 1 file changed, 3 insertions(+)