On Friday 22 January 2010, Sebastian Ott wrote: > hi Rafael, > > on s390 we have a reproduceable testcase where, after all devices were > suspended, a memory allocation results in disk IO. I know that this is > similar to the current discussion about magically changing the gpf mask, > but in our case the related allocation is triggered not by a device driver > but directly by hibernation_snapshot. The call chain looks like this: > > STACK: > 0 schedule+1796 [0x5a7af0] > 1 io_schedule+98 [0x5a82ce] > 2 sync_page_killable+4 [0x1ec424] > 3 __wait_on_bit+204 [0x5a8bc4] > 4 add_to_page_cache_locked+2 [0x1ec766] > 5 shrink_page_list+2372 [0x1fc5b0] > 6 shrink_list+2496 [0x1fd02c] > 7 shrink_zone+932 [0x1fd3e0] > 8 try_to_free_pages+668 [0x1fe4bc] > 9 __alloc_pages_nodemask+1346 [0x1f5056] > 10 __get_free_pages+76 [0x1f52dc] > 11 __build_sched_domains+60 [0x144f98] > 12 partition_sched_domains+696 [0x145dcc] > 13 update_sched_domains+100 [0x146104] > 14 notifier_call_chain+166 [0x5ae112] > 15 raw_notifier_call_chain+44 [0x1800c4] > 16 _cpu_down+586 [0x59f212] > 17 disable_nonboot_cpus+354 [0x155ad2] > 18 hibernation_snapshot+324 [0x1a7938] > 19 hibernate+304 [0x1a7bcc] > 20 state_store+130 [0x1a645e] > 21 sysfs_write_file+264 [0x2b551c] > 22 vfs_write+190 [0x23f98a] > 23 sys_write+100 [0x23fb50] > 24 sysc_noemu+16 [0x118ff6] > > a possible fix would be to call disable_nonboot_cpus before suspending the > devices.. This is going against the changes attempting to speed-up suspend and resume, such as the asynchronous suspend/resume patchset, so I don't agree with it. The real solution would be to remove the memory allocations from the _cpu_down() call path. BTW, this is one of the cases I and Ben are talking about where it's not practical to rework the code just to avoid memory allocation problems during suspend/resume. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
