Hi,
This patchset try to solve one deadlock problem which might be caused
by memory allocation with block I/O during runtime resume and block device
error handling path. Traditionly, the problem is addressed by passing
GFP_NOIO statically to mm, but that is not a effective solution, see
detailed description in patch 1's commit log.
This patch set introduces one process flag and trys to fix one deadlock
problem on block device/network device during runtime resume or usb bus reset.
The 1st one is the change on include/sched.h and mm.
The 2nd patch introduces the flag of memalloc_noio_resume on 'dev_pm_info',
and pm_runtime_set_memalloc_noio(), so that PM Core can teach mm to not
allocate mm with GFP_IOFS during the runtime_resume callback only on
device with the flag set.
The following 2 patches apply the introduced pm_runtime_set_memalloc_noio()
to mark all devices as memalloc_noio_resume in the path from the block or
network device to the root device in device tree.
The last 2 patches are applied again PM and USB subsystem to demonstrate
how to use the introduced mechanism to fix the deadlock problem.
V2:
- remove changes on 'may_writepage' and 'may_swap'(1/6)
- unset GFP_IOFS in try_to_free_pages() path(1/6)
- introduce pm_runtime_set_memalloc_noio()
- only apply the meachnism on block/network device and its ancestors
for runtime resume context
V1:
- take Minchan's change to avoid the check in alloc_page hot path
- change the helpers' style into save/restore as suggested by Alan
- memory allocation with no io in usb bus reset path for all devices
as suggested by Greg and Oliver
block/genhd.c | 8 +++++
drivers/base/power/runtime.c | 69 +++++++++++++++++++++++++++++++++++++++++-
drivers/usb/core/hub.c | 11 +++++++
include/linux/pm.h | 1 +
include/linux/pm_runtime.h | 3 ++
include/linux/sched.h | 10 ++++++
mm/page_alloc.c | 10 +++++-
mm/vmscan.c | 12 ++++++++
net/core/net-sysfs.c | 5 +++
9 files changed, 127 insertions(+), 2 deletions(-)
Thanks,
--
Ming Lei
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