<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/kernel/power, branch v4.8.10</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.8.10</id>
<link rel='self' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v4.8.10'/>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/'/>
<updated>2016-09-05T13:07:53Z</updated>
<entry>
<title>PM / QoS: avoid calling cancel_delayed_work_sync() during early boot</title>
<updated>2016-09-05T13:07:53Z</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2016-09-05T12:38:13Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=c86d06ba2818c5126078cb0cf4e0175ec381045b'/>
<id>urn:sha1:c86d06ba2818c5126078cb0cf4e0175ec381045b</id>
<content type='text'>
of_clk_init() ends up calling into pm_qos_update_request() very early
during boot where irq is expected to stay disabled.
pm_qos_update_request() uses cancel_delayed_work_sync() which
correctly assumes that irq is enabled on invocation and
unconditionally disables and re-enables it.

Gate cancel_delayed_work_sync() invocation with kevented_up() to avoid
enabling irq unexpectedly during early boot.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-and-tested-by: Qiao Zhou &lt;qiaozhou@asrmicro.com&gt;
Link: http://lkml.kernel.org/r/d2501c4c-8e7b-bea3-1b01-000b36b5dfe9@asrmicro.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'pm-sleep'</title>
<updated>2016-08-18T01:27:08Z</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2016-08-18T01:27:08Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=6c16f42a4e01ef1543fb21e594c2b25d00697649'/>
<id>urn:sha1:6c16f42a4e01ef1543fb21e594c2b25d00697649</id>
<content type='text'>
* pm-sleep:
  PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
  x86/power/64: Use __pa() for physical address computation
  PM / sleep: Update some system sleep documentation
</content>
</entry>
<entry>
<title>PM / hibernate: Fix rtree_next_node() to avoid walking off list ends</title>
<updated>2016-08-16T11:16:36Z</updated>
<author>
<name>James Morse</name>
<email>james.morse@arm.com</email>
</author>
<published>2016-08-16T09:46:38Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=924d8696751c4b9e58263bc82efdafcf875596a6'/>
<id>urn:sha1:924d8696751c4b9e58263bc82efdafcf875596a6</id>
<content type='text'>
rtree_next_node() walks the linked list of leaf nodes to find the next
block of pages in the struct memory_bitmap. If it walks off the end of
the list of nodes, it walks the list of memory zones to find the next
region of memory. If it walks off the end of the list of zones, it
returns false.

This leaves the struct bm_position's node and zone pointers pointing
at their respective struct list_heads in struct mem_zone_bm_rtree.

memory_bm_find_bit() uses struct bm_position's node and zone pointers
to avoid walking lists and trees if the next bit appears in the same
node/zone. It handles these values being stale.

Swap rtree_next_node()s 'step then test' to 'test-next then step',
this means if we reach the end of memory we return false and leave
the node and zone pointers as they were.

This fixes a panic on resume using AMD Seattle with 64K pages:
[    6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done.
[    6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds)
[    6.896453] PM: Using 3 thread(s) for decompression.
[    6.896453] PM: Loading and decompressing image data (5339 pages)...
[    7.318890] PM: Image loading progress:   0%
[    7.323395] Unable to handle kernel paging request at virtual address 00800040
[    7.330611] pgd = ffff000008df0000
[    7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000
[    7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[    7.349825] Modules linked in:
[    7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G        W I     4.8.0-rc1 #4737
[    7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016
[    7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000
[    7.375020] PC is at set_bit+0x18/0x30
[    7.378758] LR is at memory_bm_set_bit+0x24/0x30
[    7.383362] pc : [&lt;ffff00000835bbc8&gt;] lr : [&lt;ffff0000080faf18&gt;] pstate: 60000045
[    7.390743] sp : ffff8003c0283b00
[    7.473551]
[    7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020)
[    7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000)
[    7.800075] Call trace:
[    7.887097] [&lt;ffff00000835bbc8&gt;] set_bit+0x18/0x30
[    7.891876] [&lt;ffff0000080fb038&gt;] duplicate_memory_bitmap.constprop.38+0x54/0x70
[    7.899172] [&lt;ffff0000080fcc40&gt;] snapshot_write_next+0x22c/0x47c
[    7.905166] [&lt;ffff0000080fe1b4&gt;] load_image_lzo+0x754/0xa88
[    7.910725] [&lt;ffff0000080ff0a8&gt;] swsusp_read+0x144/0x230
[    7.916025] [&lt;ffff0000080fa338&gt;] load_image_and_restore+0x58/0x90
[    7.922105] [&lt;ffff0000080fa660&gt;] software_resume+0x2f0/0x338
[    7.927752] [&lt;ffff000008083350&gt;] do_one_initcall+0x38/0x11c
[    7.933314] [&lt;ffff000008b40cc0&gt;] kernel_init_freeable+0x14c/0x1ec
[    7.939395] [&lt;ffff0000087ce564&gt;] kernel_init+0x10/0xfc
[    7.944520] [&lt;ffff000008082e90&gt;] ret_from_fork+0x10/0x40
[    7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22)
[    7.955909] ---[ end trace 0024a5986e6ff323 ]---
[    7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Here struct mem_zone_bm_rtree's start_pfn has been returned instead of
struct rtree_node's addr as the node/zone pointers are corrupt after
we walked off the end of the lists during mark_unsafe_pages().

This behaviour was exposed by commit 6dbecfd345a6 ("PM / hibernate:
Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call
duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking
off the end of the memory bitmap.

Fixes: 3a20cb177961 (PM / Hibernate: Implement position keeping in radix tree)
Signed-off-by: James Morse &lt;james.morse@arm.com&gt;
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>Merge branches 'pm-sleep' and 'pm-cpufreq'</title>
<updated>2016-08-12T20:53:58Z</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2016-08-12T20:53:58Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=0aeeb3e73f5fd7faef3dce8cb590effd6ee51571'/>
<id>urn:sha1:0aeeb3e73f5fd7faef3dce8cb590effd6ee51571</id>
<content type='text'>
* pm-sleep:
  PM / hibernate: Restore processor state before using per-CPU variables
  x86/power/64: Always create temporary identity mapping correctly

* pm-cpufreq:
  cpufreq: powernv: Fix crash in gpstate_timer_handler()
</content>
</entry>
<entry>
<title>PM / hibernate: Restore processor state before using per-CPU variables</title>
<updated>2016-08-12T20:50:42Z</updated>
<author>
<name>Thomas Garnier</name>
<email>thgarnie@google.com</email>
</author>
<published>2016-08-11T21:49:29Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=62822e2ec4ad091ba31f823f577ef80db52e3c2c'/>
<id>urn:sha1:62822e2ec4ad091ba31f823f577ef80db52e3c2c</id>
<content type='text'>
Restore the processor state before calling any other functions to
ensure per-CPU variables can be used with KASLR memory randomization.

Tracing functions use per-CPU variables (GS based on x86) and one was
called just before restoring the processor state fully. It resulted
in a double fault when both the tracing &amp; the exception handler
functions tried to use a per-CPU variable.

Fixes: bb3632c6101b (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov &lt;bp@suse.de&gt;
Reported-by: Jiri Kosina &lt;jikos@kernel.org&gt;
Tested-by: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Tested-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
Signed-off-by: Thomas Garnier &lt;thgarnie@google.com&gt;
Acked-by: Pavel Machek &lt;pavel@ucw.cz&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>mm, vmscan: move LRU lists to node</title>
<updated>2016-07-28T23:07:41Z</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2016-07-28T22:45:31Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=599d0c954f91d0689c9bb421b5bc04ea02437a41'/>
<id>urn:sha1:599d0c954f91d0689c9bb421b5bc04ea02437a41</id>
<content type='text'>
This moves the LRU lists from the zone to the node and related data such
as counters, tracing, congestion tracking and writeback tracking.

Unfortunately, due to reclaim and compaction retry logic, it is
necessary to account for the number of LRU pages on both zone and node
logic.  Most reclaim logic is based on the node counters but the retry
logic uses the zone counters which do not distinguish inactive and
active sizes.  It would be possible to leave the LRU counters on a
per-zone basis but it's a heavier calculation across multiple cache
lines that is much more frequent than the retry checks.

Other than the LRU counters, this is mostly a mechanical patch but note
that it introduces a number of anomalies.  For example, the scans are
per-zone but using per-node counters.  We also mark a node as congested
when a zone is congested.  This causes weird problems that are fixed
later but is easier to review.

In the event that there is excessive overhead on 32-bit systems due to
the nodes being on LRU then there are two potential solutions

1. Long-term isolation of highmem pages when reclaim is lowmem

   When pages are skipped, they are immediately added back onto the LRU
   list. If lowmem reclaim persisted for long periods of time, the same
   highmem pages get continually scanned. The idea would be that lowmem
   keeps those pages on a separate list until a reclaim for highmem pages
   arrives that splices the highmem pages back onto the LRU. It potentially
   could be implemented similar to the UNEVICTABLE list.

   That would reduce the skip rate with the potential corner case is that
   highmem pages have to be scanned and reclaimed to free lowmem slab pages.

2. Linear scan lowmem pages if the initial LRU shrink fails

   This will break LRU ordering but may be preferable and faster during
   memory pressure than skipping LRU pages.

Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2016-07-27T00:29:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-07-27T00:29:07Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=6453dbdda30428a3c56568c96fe70ea3612f07e2'/>
<id>urn:sha1:6453dbdda30428a3c56568c96fe70ea3612f07e2</id>
<content type='text'>
Pull power management updates from Rafael  Wysocki:
 "Again, the majority of changes go into the cpufreq subsystem, but
  there are no big features this time.  The cpufreq changes that stand
  out somewhat are the governor interface rework and improvements
  related to the handling of frequency tables.  Apart from those, there
  are fixes and new device/CPU IDs in drivers, cleanups and an
  improvement of the new schedutil governor.

  Next, there are some changes in the hibernation core, including a fix
  for a nasty problem related to the MONITOR/MWAIT usage by CPU offline
  during resume from hibernation, a few core improvements related to
  memory management during resume, a couple of additional debug features
  and cleanups.

  Finally, we have some fixes and cleanups in the devfreq subsystem,
  generic power domains framework improvements related to system
  suspend/resume, support for some new chips in intel_idle and in the
  power capping RAPL driver, a new version of the AnalyzeSuspend utility
  and some assorted fixes and cleanups.

  Specifics:

   - Rework the cpufreq governor interface to make it more
     straightforward and modify the conservative governor to avoid using
     transition notifications (Rafael Wysocki).

   - Rework the handling of frequency tables by the cpufreq core to make
     it more efficient (Viresh Kumar).

   - Modify the schedutil governor to reduce the number of wakeups it
     causes to occur in cases when the CPU frequency doesn't need to be
     changed (Steve Muckle, Viresh Kumar).

   - Fix some minor issues and clean up code in the cpufreq core and
     governors (Rafael Wysocki, Viresh Kumar).

   - Add Intel Broxton support to the intel_pstate driver (Srinivas
     Pandruvada).

   - Fix problems related to the config TDP feature and to the validity
     of the MSR_HWP_INTERRUPT register in intel_pstate (Jan Kiszka,
     Srinivas Pandruvada).

   - Make intel_pstate update the cpu_frequency tracepoint even if the
     frequency doesn't change to avoid confusing powertop (Rafael
     Wysocki).

   - Clean up the usage of __init/__initdata in intel_pstate, mark some
     of its internal variables as __read_mostly and drop an unused
     structure element from it (Jisheng Zhang, Carsten Emde).

   - Clean up the usage of some duplicate MSR symbols in intel_pstate
     and turbostat (Srinivas Pandruvada).

   - Update/fix the powernv, s3c24xx and mvebu cpufreq drivers (Akshay
     Adiga, Viresh Kumar, Ben Dooks).

   - Fix a regression (introduced during the 4.5 cycle) in the
     pcc-cpufreq driver by reverting the problematic commit (Andreas
     Herrmann).

   - Add support for Intel Denverton to intel_idle, clean up Broxton
     support in it and make it explicitly non-modular (Jacob Pan, Jan
     Beulich, Paul Gortmaker).

   - Add support for Denverton and Ivy Bridge server to the Intel RAPL
     power capping driver and make it more careful about the handing of
     MSRs that may not be present (Jacob Pan, Xiaolong Wang).

   - Fix resume from hibernation on x86-64 by making the CPU offline
     during resume avoid using MONITOR/MWAIT in the "play dead" loop
     which may lead to an inadvertent "revival" of a "dead" CPU and a
     page fault leading to a kernel crash from it (Rafael Wysocki).

   - Make memory management during resume from hibernation more
     straightforward (Rafael Wysocki).

   - Add debug features that should help to detect problems related to
     hibernation and resume from it (Rafael Wysocki, Chen Yu).

   - Clean up hibernation core somewhat (Rafael Wysocki).

   - Prevent KASAN from instrumenting the hibernation core which leads
     to large numbers of false-positives from it (James Morse).

   - Prevent PM (hibernate and suspend) notifiers from being called
     during the cleanup phase if they have not been called during the
     corresponding preparation phase which is possible if one of the
     other notifiers returns an error at that time (Lianwei Wang).

   - Improve suspend-related debug printout in the tasks freezer and
     clean up suspend-related console handling (Roger Lu, Borislav
     Petkov).

   - Update the AnalyzeSuspend script in the kernel sources to version
     4.2 (Todd Brandt).

   - Modify the generic power domains framework to make it handle system
     suspend/resume better (Ulf Hansson).

   - Make the runtime PM framework avoid resuming devices synchronously
     when user space changes the runtime PM settings for them and
     improve its error reporting (Rafael Wysocki, Linus Walleij).

   - Fix error paths in devfreq drivers (exynos, exynos-ppmu,
     exynos-bus) and in the core, make some devfreq code explicitly
     non-modular and change some of it into tristate (Bartlomiej
     Zolnierkiewicz, Peter Chen, Paul Gortmaker).

   - Add DT support to the generic PM clocks management code and make it
     export some more symbols (Jon Hunter, Paul Gortmaker).

   - Make the PCI PM core code slightly more robust against possible
     driver errors (Andy Shevchenko).

   - Make it possible to change DESTDIR and PREFIX in turbostat (Andy
     Shevchenko)"

* tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
  Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
  PM / hibernate: Introduce test_resume mode for hibernation
  cpufreq: export cpufreq_driver_resolve_freq()
  cpufreq: Disallow -&gt;resolve_freq() for drivers providing -&gt;target_index()
  PCI / PM: check all fields in pci_set_platform_pm()
  cpufreq: acpi-cpufreq: use cached frequency mapping when possible
  cpufreq: schedutil: map raw required frequency to driver frequency
  cpufreq: add cpufreq_driver_resolve_freq()
  cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT
  intel_pstate: Update cpu_frequency tracepoint every time
  cpufreq: intel_pstate: clean remnant struct element
  PM / tools: scripts: AnalyzeSuspend v4.2
  x86 / hibernate: Use hlt_play_dead() when resuming from hibernation
  cpufreq: powernv: Replacing pstate_id with frequency table index
  intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()
  PM / hibernate: Image data protection during restoration
  PM / hibernate: Add missing braces in __register_nosave_region()
  PM / hibernate: Clean up comments in snapshot.c
  PM / hibernate: Clean up function headers in snapshot.c
  PM / hibernate: Add missing braces in hibernate_setup()
  ...
</content>
</entry>
<entry>
<title>Merge branch 'for-4.8/core' of git://git.kernel.dk/linux-block</title>
<updated>2016-07-26T22:03:07Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-07-26T22:03:07Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=d05d7f40791ccbb6e543cc5dd6a6aa08fc71d635'/>
<id>urn:sha1:d05d7f40791ccbb6e543cc5dd6a6aa08fc71d635</id>
<content type='text'>
Pull core block updates from Jens Axboe:

   - the big change is the cleanup from Mike Christie, cleaning up our
     uses of command types and modified flags.  This is what will throw
     some merge conflicts

   - regression fix for the above for btrfs, from Vincent

   - following up to the above, better packing of struct request from
     Christoph

   - a 2038 fix for blktrace from Arnd

   - a few trivial/spelling fixes from Bart Van Assche

   - a front merge check fix from Damien, which could cause issues on
     SMR drives

   - Atari partition fix from Gabriel

   - convert cfq to highres timers, since jiffies isn't granular enough
     for some devices these days.  From Jan and Jeff

   - CFQ priority boost fix idle classes, from me

   - cleanup series from Ming, improving our bio/bvec iteration

   - a direct issue fix for blk-mq from Omar

   - fix for plug merging not involving the IO scheduler, like we do for
     other types of merges.  From Tahsin

   - expose DAX type internally and through sysfs.  From Toshi and Yigal

* 'for-4.8/core' of git://git.kernel.dk/linux-block: (76 commits)
  block: Fix front merge check
  block: do not merge requests without consulting with io scheduler
  block: Fix spelling in a source code comment
  block: expose QUEUE_FLAG_DAX in sysfs
  block: add QUEUE_FLAG_DAX for devices to advertise their DAX support
  Btrfs: fix comparison in __btrfs_map_block()
  block: atari: Return early for unsupported sector size
  Doc: block: Fix a typo in queue-sysfs.txt
  cfq-iosched: Charge at least 1 jiffie instead of 1 ns
  cfq-iosched: Fix regression in bonnie++ rewrite performance
  cfq-iosched: Convert slice_resid from u64 to s64
  block: Convert fifo_time from ulong to u64
  blktrace: avoid using timespec
  block/blk-cgroup.c: Declare local symbols static
  block/bio-integrity.c: Add #include "blk.h"
  block/partition-generic.c: Remove a set-but-not-used variable
  block: bio: kill BIO_MAX_SIZE
  cfq-iosched: temporarily boost queue priority for idle classes
  block: drbd: avoid to use BIO_MAX_SIZE
  block: bio: remove BIO_MAX_SECTORS
  ...
</content>
</entry>
<entry>
<title>PM / hibernate: Introduce test_resume mode for hibernation</title>
<updated>2016-07-22T11:57:23Z</updated>
<author>
<name>Chen Yu</name>
<email>yu.c.chen@intel.com</email>
</author>
<published>2016-07-22T02:30:47Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=fe12c00d21bb4985fa8da282942250be21e7dd59'/>
<id>urn:sha1:fe12c00d21bb4985fa8da282942250be21e7dd59</id>
<content type='text'>
test_resume mode is to verify if the snapshot data
written to swap device can be successfully restored
to memory. It is useful to ease the debugging process
on hibernation, since this mode can not only bypass
the BIOSes/bootloader, but also the system re-initialization.

To avoid the risk to break the filesystm on persistent storage,
this patch resumes the image with tasks frozen.

For example:
echo test_resume &gt; /sys/power/disk
echo disk &gt; /sys/power/state

[  187.306470] PM: Image saving progress:  70%
[  187.395298] PM: Image saving progress:  80%
[  187.476697] PM: Image saving progress:  90%
[  187.554641] PM: Image saving done.
[  187.558896] PM: Wrote 594600 kbytes in 0.90 seconds (660.66 MB/s)
[  187.566000] PM: S|
[  187.589742] PM: Basic memory bitmaps freed
[  187.594694] PM: Checking hibernation image
[  187.599865] PM: Image signature found, resuming
[  187.605209] PM: Loading hibernation image.
[  187.665753] PM: Basic memory bitmaps created
[  187.691397] PM: Using 3 thread(s) for decompression.
[  187.691397] PM: Loading and decompressing image data (148650 pages)...
[  187.889719] PM: Image loading progress:   0%
[  188.100452] PM: Image loading progress:  10%
[  188.244781] PM: Image loading progress:  20%
[  189.057305] PM: Image loading done.
[  189.068793] PM: Image successfully loaded

Suggested-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>x86 / hibernate: Use hlt_play_dead() when resuming from hibernation</title>
<updated>2016-07-15T20:42:48Z</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2016-07-14T01:55:23Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=406f992e4a372dafbe3c2cff7efbb2002a5c8ebd'/>
<id>urn:sha1:406f992e4a372dafbe3c2cff7efbb2002a5c8ebd</id>
<content type='text'>
On Intel hardware, native_play_dead() uses mwait_play_dead() by
default and only falls back to the other methods if that fails.
That also happens during resume from hibernation, when the restore
(boot) kernel runs disable_nonboot_cpus() to take all of the CPUs
except for the boot one offline.

However, that is problematic, because the address passed to
__monitor() in mwait_play_dead() is likely to be written to in the
last phase of hibernate image restoration and that causes the "dead"
CPU to start executing instructions again.  Unfortunately, the page
containing the address in that CPU's instruction pointer may not be
valid any more at that point.

First, that page may have been overwritten with image kernel memory
contents already, so the instructions the CPU attempts to execute may
simply be invalid.  Second, the page tables previously used by that
CPU may have been overwritten by image kernel memory contents, so the
address in its instruction pointer is impossible to resolve then.

A report from Varun Koyyalagunta and investigation carried out by
Chen Yu show that the latter sometimes happens in practice.

To prevent it from happening, temporarily change the smp_ops.play_dead
pointer during resume from hibernation so that it points to a special
"play dead" routine which uses hlt_play_dead() and avoids the
inadvertent "revivals" of "dead" CPUs this way.

A slightly unpleasant consequence of this change is that if the
system is hibernated with one or more CPUs offline, it will generally
draw more power after resume than it did before hibernation, because
the physical state entered by CPUs via hlt_play_dead() is higher-power
than the mwait_play_dead() one in the majority of cases.  It is
possible to work around this, but it is unclear how much of a problem
that's going to be in practice, so the workaround will be implemented
later if it turns out to be necessary.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=106371
Reported-by: Varun Koyyalagunta &lt;cpudebug@centtech.com&gt;
Original-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Tested-by: Chen Yu &lt;yu.c.chen@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
</entry>
</feed>
