user/sven/linux.git/kernel/power/snapshot.c, branch v4.9.142

PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO

2016-09-13T00:35:27Z

PAGE_POISONING_ZERO disables zeroing new pages on alloc, they are poisoned (zeroed) as they become available. In the hibernate use case, free pages will appear in the system without being cleared, left there by the loading kernel. This patch will make sure free pages are cleared on resume when PAGE_POISONING_ZERO is enabled. We free the pages just after resume because we can't do it later: going through any device resume code might allocate some memory and invalidate the free pages bitmap. Thus we don't need to disable hibernation when PAGE_POISONING_ZERO is enabled. Signed-off-by: Anisse Astier Reviewed-by: Kees Cook Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki

Merge branch 'pm-sleep'

2016-08-18T01:27:08Z

* 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

PM / hibernate: Fix rtree_next_node() to avoid walking off list ends

2016-08-16T11:16:36Z

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 : [] lr : [] 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] [] set_bit+0x18/0x30 [ 7.891876] [] duplicate_memory_bitmap.constprop.38+0x54/0x70 [ 7.899172] [] snapshot_write_next+0x22c/0x47c [ 7.905166] [] load_image_lzo+0x754/0xa88 [ 7.910725] [] swsusp_read+0x144/0x230 [ 7.916025] [] load_image_and_restore+0x58/0x90 [ 7.922105] [] software_resume+0x2f0/0x338 [ 7.927752] [] do_one_initcall+0x38/0x11c [ 7.933314] [] kernel_init_freeable+0x14c/0x1ec [ 7.939395] [] kernel_init+0x10/0xfc [ 7.944520] [] 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 [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki

mm, vmscan: move LRU lists to node

2016-07-28T23:07:41Z

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 Acked-by: Johannes Weiner Acked-by: Vlastimil Babka Cc: Hillf Danton Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

PM / hibernate: Image data protection during restoration

2016-07-10T00:12:10Z

Make it possible to protect all pages holding image data during hibernate image restoration by setting them read-only (so as to catch attempts to write to those pages after image data have been stored in them). This adds overhead to image restoration code (it may cause large page mappings to be split as a result of page flags changes) and the errors it protects against should never happen in theory, so the feature is only active after passing hibernate=protect_image to the command line of the restore kernel. Also it only is built if CONFIG_DEBUG_RODATA is set. Signed-off-by: Rafael J. Wysocki

PM / hibernate: Add missing braces in __register_nosave_region()

2016-07-09T23:37:35Z

One branch of an if/else statement in __register_nosave_region() is formatted against the kernel coding style which causes the code to look slightly odd. To fix that, add missing braces to it. No functional changes. Signed-off-by: Rafael J. Wysocki

PM / hibernate: Clean up comments in snapshot.c

2016-07-09T23:37:26Z

Many comments in kernel/power/snapshot.c do not follow the general comment formatting rules. They look odd, some of them are outdated too, some are hard to parse and generally difficult to understand. Clean them up to make them easier to comprehend. No functional changes. Signed-off-by: Rafael J. Wysocki

PM / hibernate: Clean up function headers in snapshot.c

2016-07-09T23:37:20Z

The formatting of some function headers in kernel/power/snapshot.c is not consistent with the general kernel coding style and with the formatting of some other function headers in the same file. Make all of them follow the same formatting convention. No functional changes. Signed-off-by: Rafael J. Wysocki

PM / hibernate: Recycle safe pages after image restoration

2016-07-01T23:52:10Z

One of the memory bitmaps used by the hibernation image restoration code is freed after the image has been loaded. That is not quite efficient, though, because the memory pages used for building that bitmap are known to be safe (ie. they were not used by the image kernel before hibernation) and the arch-specific code finalizing the image restoration may need them. In that case it needs to allocate those pages again via the memory management subsystem, check if they are really safe again by consulting the other bitmaps and so on. To avoid that, recycle those pages by putting them into the global list of known safe pages so that they can be given to the arch code right away when necessary. Signed-off-by: Rafael J. Wysocki

PM / hibernate: Simplify mark_unsafe_pages()

2016-07-01T23:52:09Z

Rework mark_unsafe_pages() to use a simpler method of clearing all bits in free_pages_map and to set the bits for the "unsafe" pages (ie. pages that were used by the image kernel before hibernation) with the help of duplicate_memory_bitmap(). For this purpose, move the pfn_valid() check from mark_unsafe_pages() to unpack_orig_pfns() where the "unsafe" pages are discovered. Signed-off-by: Rafael J. Wysocki