Re: + git-nfs-vs-nfs-convert-to-new-aops.patch added to -mm tree

From: Peter Zijlstra
Date: Mon Sep 24 2007 - 09:53:24 EST


On Thu, 20 Sep 2007 13:20:47 +0200 Peter Zijlstra
<peterz@xxxxxxxxxxxxx> wrote:

> /me continues the mmap write on nfs adventure...

My test prog reliably hangs like so:

mm_tester D 000000000040b305 0 2701 2699
6042cef0 602ca520 617dfa50 617de000 617dfa90 60010b62 617dfa80 6002785d
617de000 60583840 6042bcc0 6042ca40 617dfad0 6019e3c2 00080000 617de000
617dfae0 ffffc0e7 617dfb38 00000002 617dfb60 6019eb20 616e7ae0 6048bd00 Call Trace:
Call Trace:
617dfa58: [<60010b62>] _switch_to+0x81/0xf5
617dfa68: [<6002785d>] pick_next_entity+0x1a/0x38
617dfa98: [<6019e3c2>] schedule+0x1b8/0x23f
617dfad8: [<6019eb20>] schedule_timeout+0xa2/0xcb
617dfaf8: [<60035dc3>] process_timeout+0x0/0xb
617dfb10: [<6019eb1b>] schedule_timeout+0x9d/0xcb
617dfb68: [<6019ea62>] io_schedule_timeout+0xf/0x17
617dfb78: [<6004f0d1>] sync_page+0x6b/0x6f
617dfb88: [<6019ecd3>] __wait_on_bit_lock+0x42/0x78
617dfbb0: [<6004fa2a>] find_lock_page+0xb4/0x155
617dfbc8: [<6004f806>] __lock_page+0x73/0xb3
617dfbf0: [<60040585>] wake_bit_function+0x0/0x2a
617dfc38: [<6004fa3c>] find_lock_page+0xc6/0x155
617dfc48: [<600570c9>] do_page_cache_readahead+0x52/0x5f
617dfc78: [<600508ea>] filemap_fault+0x151/0x2c2
617dfce8: [<6005e9c8>] __do_fault+0x6c/0x444
617dfd68: [<6005edd1>] do_linear_fault+0x31/0x33
617dfd88: [<6005f04e>] handle_mm_fault+0x130/0x228
617dfda8: [<6011e2d7>] __up_read+0x73/0x7b
617dfde8: [<600131d4>] handle_page_fault+0x120/0x2d9
617dfe08: [<601242c8>] tty_write+0x1f7/0x212
617dfe48: [<60013513>] segv+0xac/0x286
617dff28: [<60013461>] segv_handler+0x68/0x6e
617dff48: [<600232c9>] get_skas_faultinfo+0x9c/0xa1
617dff68: [<6002386f>] userspace+0x13a/0x19d
617dffc8: [<60010d4c>] fork_handler+0x86/0x8d


A new nfs_sync_page() method tells me:

sleeping on page: 0000000060ba05c0 held by: [<000000006004f5d1>] add_to_page_cache_lru+0xf/0x3a


And a rather crude printk() and dump_stack() in add_to_page_cache_lru()
match:

page: 0000000060ba05c0
Call Trace:
605eda88: [<6004f5f4>] add_to_page_cache_lru+0x32/0x3a
605edaa8: [<60056ddc>] read_cache_pages+0x4a/0x8f
605edae8: [<600f8e49>] nfs_readpages+0x116/0x164
605edb38: [<600f86bb>] nfs_pagein_one+0x0/0xd2
605edb98: [<60056e58>] read_pages+0x37/0x9b
605edbd8: [<60056fbc>] __do_page_cache_readahead+0x100/0x146
605edc48: [<600570dd>] do_page_cache_readahead+0x52/0x5f
605edc78: [<600508f4>] filemap_fault+0x145/0x2c2
605edca8: [<60022b7d>] run_syscall_stub+0xd1/0xdd
605edce8: [<6005e9dc>] __do_fault+0x6c/0x444
605edd68: [<6005ede5>] do_linear_fault+0x31/0x33
605edd88: [<6005f062>] handle_mm_fault+0x130/0x228
605edda8: [<6011e2eb>] __up_read+0x73/0x7b
605edde8: [<600131d4>] handle_page_fault+0x120/0x2d9
605ede08: [<601242dc>] tty_write+0x1f7/0x212
605ede48: [<60013513>] segv+0xac/0x286
605edf28: [<60013461>] segv_handler+0x68/0x6e
605edf48: [<600232c9>] get_skas_faultinfo+0x9c/0xa1
605edf68: [<6002386f>] userspace+0x13a/0x19d
605edfc8: [<60010d4c>] fork_handler+0x86/0x8d


/me wonders, missing RPC request or locking mistake...
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