On Wed, Dec 08, 2010 at 12:47:42PM +1100, Nick Piggin wrote: > On Wed, Dec 8, 2010 at 8:56 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > > On Sat, Nov 27, 2010 at 09:15:58PM +1100, Nick Piggin wrote: > >> > >> git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin.git vfs-scale-working > >> > >> Here is an new set of vfs patches for review, not that there was much interest > >> last time they were posted. It is structured like: > >> > >> * preparation patches > >> * introduce new locks to take over dcache_lock, then remove it > >> * cleaning up and reworking things for new locks > >> * rcu-walk path walking > >> * start on some fine grained locking steps > > > > Stress test doing: > > > > single thread 50M inode create > > single thread rm -rf > > 2-way 50M inode create > > 2-way rm -rf > > 4-way 50M inode create > > 4-way rm -rf > > 8-way 50M inode create > > 8-way rm -rf > > 8-way 250M inode create > > 8-way rm -rf > > > > Failed about 5 minutes into the "4-way rm -rf" (~3 hours into the test) > > with a CPU stuck spinning on here: > > > > [37372.084012] NMI backtrace for cpu 5 > > [37372.084012] CPU 5 > > [37372.084012] Modules linked in: > > [37372.084012] > > [37372.084012] Pid: 15214, comm: rm Not tainted 2.6.37-rc4-dgc+ #797 /Bochs > > [37372.084012] RIP: 0010:[<ffffffff810643c4>] [<ffffffff810643c4>] __ticket_spin_lock+0x14/0x20 > > [37372.084012] RSP: 0018:ffff880114643c98 EFLAGS: 00000213 > > [37372.084012] RAX: 0000000000008801 RBX: ffff8800687be6c0 RCX: ffff8800c4eb2688 > > [37372.084012] RDX: ffff880114643d38 RSI: ffff8800dfd4ea80 RDI: ffff880114643d14 > > [37372.084012] RBP: ffff880114643c98 R08: 0000000000000003 R09: 0000000000000000 > > [37372.084012] R10: 0000000000000000 R11: dead000000200200 R12: ffff880114643d14 > > [37372.084012] R13: ffff880114643cb8 R14: ffff880114643d38 R15: ffff8800687be71c > > [37372.084012] FS: 00007fd6d7c93700(0000) GS:ffff8800dfd40000(0000) knlGS:0000000000000000 > > [37372.084012] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > > [37372.084012] CR2: 0000000000bbd108 CR3: 0000000107146000 CR4: 00000000000006e0 > > [37372.084012] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > [37372.084012] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > [37372.084012] Process rm (pid: 15214, threadinfo ffff880114642000, task ffff88011b16f890) > > [37372.084012] Stack: > > [37372.084012] ffff880114643ca8 ffffffff81ad044e ffff880114643cf8 ffffffff81167ae7 > > [37372.084012] 0000000000000000 ffff880114643d38 000000000000000e ffff88011901d800 > > [37372.084012] ffff8800cdb7cf5c ffff88011901d8e0 0000000000000000 0000000000000000 > > [37372.084012] Call Trace: > > [37372.084012] [<ffffffff81ad044e>] _raw_spin_lock+0xe/0x20 > > [37372.084012] [<ffffffff81167ae7>] shrink_dentry_list+0x47/0x370 > > [37372.084012] [<ffffffff81167f5e>] __shrink_dcache_sb+0x14e/0x1e0 > > [37372.084012] [<ffffffff81168456>] shrink_dcache_parent+0x276/0x2d0 > > [37372.084012] [<ffffffff81ad044e>] ? _raw_spin_lock+0xe/0x20 > > [37372.084012] [<ffffffff8115daa2>] dentry_unhash+0x42/0x80 > > [37372.084012] [<ffffffff8115db48>] vfs_rmdir+0x68/0x100 > > [37372.084012] [<ffffffff8115fd93>] do_rmdir+0x113/0x130 > > [37372.084012] [<ffffffff8114f5ad>] ? filp_close+0x5d/0x90 > > [37372.084012] [<ffffffff8115fde5>] sys_unlinkat+0x35/0x40 > > [37372.084012] [<ffffffff8103a002>] system_call_fastpath+0x16/0x1b > > OK good, with any luck, that's the same bug. > > Is this XFS? Yes. > Is there any concurrent activity happening on the same dentries? Not from an application perspective. > Ie. are the rm -rf threads running on the same directories, No, each thread operating on a different directory. > or is there any reclaim happening in the background? IIRC, kswapd was consuming about 5-10% of a CPU during parallel unlink tests. Mainly reclaiming XFS inodes, I think, but there may be dentry cache reclaim going as well. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
