pm24.git/mm, branch v5.2-rc2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98

2019-05-24T15:37:54Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your optional any later version of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Richard Fontana Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.713472955@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46Z

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier for more missed files

2019-05-21T08:50:45Z

Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45Z

Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

Merge branch 'akpm' (patches from Andrew)

2019-05-19T19:15:32Z

Merge yet more updates from Andrew Morton: "A few final bits: - large changes to vmalloc, yielding large performance benefits - tweak the console-flush-on-panic code - a few fixes" * emailed patches from Andrew Morton : panic: add an option to replay all the printk message in buffer initramfs: don't free a non-existent initrd fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going into workqueue when umount mm/compaction.c: correct zone boundary handling when isolating pages from a pageblock mm/vmap: add DEBUG_AUGMENT_LOWEST_MATCH_CHECK macro mm/vmap: add DEBUG_AUGMENT_PROPAGATE_CHECK macro mm/vmalloc.c: keep track of free blocks for vmap allocation

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-19T17:23:24Z

Pull core fixes from Ingo Molnar: "This fixes a particularly thorny munmap() bug with MPX, plus fixes a host build environment assumption in objtool" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Allow AR to be overridden with HOSTAR x86/mpx, mm/core: Fix recursive munmap() corruption

mm/compaction.c: correct zone boundary handling when isolating pages from a pageblock

2019-05-18T22:52:26Z

syzbot reported the following error from a tree with a head commit of baf76f0c58ae ("slip: make slhc_free() silently accept an error pointer") BUG: unable to handle kernel paging request at ffffea0003348000 #PF error: [normal kernel read fault] PGD 12c3f9067 P4D 12c3f9067 PUD 12c3f8067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 28916 Comm: syz-executor.2 Not tainted 5.1.0-rc6+ #89 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline] RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline] RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579 Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38 ff ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31 ff 49 c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246 RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000 RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001 RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000 R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000 FS: 00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0 Call Trace: fast_isolate_around mm/compaction.c:1243 [inline] fast_isolate_freepages mm/compaction.c:1418 [inline] isolate_freepages mm/compaction.c:1438 [inline] compaction_alloc+0x1aee/0x22e0 mm/compaction.c:1550 There is no reproducer and it is difficult to hit -- 1 crash every few days. The issue is very similar to the fix in commit 6b0868c820ff ("mm/compaction.c: correct zone boundary handling when resetting pageblock skip hints"). When isolating free pages around a target pageblock, the boundary handling is off by one and can stray into the next pageblock. Triggering the syzbot error requires that the end of pageblock is section or zone aligned, and that the next section is unpopulated. A more subtle consequence of the bug is that pageblocks were being improperly used as migration targets which potentially hurts fragmentation avoidance in the long-term one page at a time. A debugging patch revealed that it's definitely possible to stray outside of a pageblock which is not intended. While syzbot cannot be used to verify this patch, it was confirmed that the debugging warning no longer triggers with this patch applied. It has also been confirmed that the THP allocation stress tests are not degraded by this patch. Link: http://lkml.kernel.org/r/20190510182124.GI18914@techsingularity.net Fixes: e332f741a8dd ("mm, compaction: be selective about what pageblocks to clear skip hints") Signed-off-by: Mel Gorman Reported-by: syzbot+d84c80f9fe26a0f7a734@syzkaller.appspotmail.com Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Qian Cai Cc: Michal Hocko Cc: Vlastimil Babka Cc: # v5.1+ Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmap: add DEBUG_AUGMENT_LOWEST_MATCH_CHECK macro

2019-05-18T22:52:26Z

This macro adds some debug code to check that vmap allocations are happened in ascending order. By default this option is set to 0 and not active. It requires recompilation of the kernel to activate it. Set to 1, compile the kernel. [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-4-urezki@gmail.com Link: http://lkml.kernel.org/r/20190402162531.10888-4-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Roman Gushchin Cc: Ingo Molnar Cc: Joel Fernandes Cc: Matthew Wilcox Cc: Michal Hocko Cc: Oleksiy Avramchenko Cc: Steven Rostedt Cc: Tejun Heo Cc: Thomas Garnier Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmap: add DEBUG_AUGMENT_PROPAGATE_CHECK macro

2019-05-18T22:52:26Z

This macro adds some debug code to check that the augment tree is maintained correctly, meaning that every node contains valid subtree_max_size value. By default this option is set to 0 and not active. It requires recompilation of the kernel to activate it. Set to 1, compile the kernel. [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-3-urezki@gmail.com Link: http://lkml.kernel.org/r/20190402162531.10888-3-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Roman Gushchin Cc: Ingo Molnar Cc: Joel Fernandes Cc: Matthew Wilcox Cc: Michal Hocko Cc: Oleksiy Avramchenko Cc: Steven Rostedt Cc: Tejun Heo Cc: Thomas Garnier Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: keep track of free blocks for vmap allocation

2019-05-18T22:52:26Z

Patch series "improve vmap allocation", v3. Objective --------- Please have a look for the description at: https://lkml.org/lkml/2018/10/19/786 but let me also summarize it a bit here as well. The current implementation has O(N) complexity. Requests with different permissive parameters can lead to long allocation time. When i say "long" i mean milliseconds. Description ----------- This approach organizes the KVA memory layout into free areas of the 1-ULONG_MAX range, i.e. an allocation is done over free areas lookups, instead of finding a hole between two busy blocks. It allows to have lower number of objects which represent the free space, therefore to have less fragmented memory allocator. Because free blocks are always as large as possible. It uses the augment tree where all free areas are sorted in ascending order of va->va_start address in pair with linked list that provides O(1) access to prev/next elements. Since the tree is augment, we also maintain the "subtree_max_size" of VA that reflects a maximum available free block in its left or right sub-tree. Knowing that, we can easily traversal toward the lowest (left most path) free area. Allocation: ~O(log(N)) complexity. It is sequential allocation method therefore tends to maximize locality. The search is done until a first suitable block is large enough to encompass the requested parameters. Bigger areas are split. I copy paste here the description of how the area is split, since i described it in https://lkml.org/lkml/2018/10/19/786 A free block can be split by three different ways. Their names are FL_FIT_TYPE, LE_FIT_TYPE/RE_FIT_TYPE and NE_FIT_TYPE, i.e. they correspond to how requested size and alignment fit to a free block. FL_FIT_TYPE - in this case a free block is just removed from the free list/tree because it fully fits. Comparing with current design there is an extra work with rb-tree updating. LE_FIT_TYPE/RE_FIT_TYPE - left/right edges fit. In this case what we do is just cutting a free block. It is as fast as a current design. Most of the vmalloc allocations just end up with this case, because the edge is always aligned to 1. NE_FIT_TYPE - Is much less common case. Basically it happens when requested size and alignment does not fit left nor right edges, i.e. it is between them. In this case during splitting we have to build a remaining left free area and place it back to the free list/tree. Comparing with current design there are two extra steps. First one is we have to allocate a new vmap_area structure. Second one we have to insert that remaining free block to the address sorted list/tree. In order to optimize a first case there is a cache with free_vmap objects. Instead of allocating from slab we just take an object from the cache and reuse it. Second one is pretty optimized. Since we know a start point in the tree we do not do a search from the top. Instead a traversal begins from a rb-tree node we split. De-allocation. ~O(log(N)) complexity. An area is not inserted straight away to the tree/list, instead we identify the spot first, checking if it can be merged around neighbors. The list provides O(1) access to prev/next, so it is pretty fast to check it. Summarizing. If merged then large coalesced areas are created, if not the area is just linked making more fragments. There is one more thing that i should mention here. After modification of VA node, its subtree_max_size is updated if it was/is the biggest area in its left or right sub-tree. Apart of that it can also be populated back to upper levels to fix the tree. For more details please have a look at the __augment_tree_propagate_from() function and the description. Tests and stressing ------------------- I use the "test_vmalloc.sh" test driver available under "tools/testing/selftests/vm/" since 5.1-rc1 kernel. Just trigger "sudo ./test_vmalloc.sh" to find out how to deal with it. Tested on different platforms including x86_64/i686/ARM64/x86_64_NUMA. Regarding last one, i do not have any physical access to NUMA system, therefore i emulated it. The time of stressing is days. If you run the test driver in "stress mode", you also need the patch that is in Andrew's tree but not in Linux 5.1-rc1. So, please apply it: http://git.cmpxchg.org/cgit.cgi/linux-mmotm.git/commit/?id=e0cf7749bade6da318e98e934a24d8b62fab512c After massive testing, i have not identified any problems like memory leaks, crashes or kernel panics. I find it stable, but more testing would be good. Performance analysis -------------------- I have used two systems to test. One is i5-3320M CPU @ 2.60GHz and another is HiKey960(arm64) board. i5-3320M runs on 4.20 kernel, whereas Hikey960 uses 4.15 kernel. I have both system which could run on 5.1-rc1 as well, but the results have not been ready by time i an writing this. Currently it consist of 8 tests. There are three of them which correspond to different types of splitting(to compare with default). We have 3 ones(see above). Another 5 do allocations in different conditions. a) sudo ./test_vmalloc.sh performance When the test driver is run in "performance" mode, it runs all available tests pinned to first online CPU with sequential execution test order. We do it in order to get stable and repeatable results. Take a look at time difference in "long_busy_list_alloc_test". It is not surprising because the worst case is O(N). # i5-3320M How many cycles all tests took: CPU0=646919905370(default) cycles vs CPU0=193290498550(patched) cycles # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_patched.txt # Hikey960 8x CPUs How many cycles all tests took: CPU0=3478683207 cycles vs CPU0=463767978 cycles # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_patched.txt b) time sudo ./test_vmalloc.sh test_repeat_count=1 With this configuration, all tests are run on all available online CPUs. Before running each CPU shuffles its tests execution order. It gives random allocation behaviour. So it is rough comparison, but it puts in the picture for sure. # i5-3320M vs real 101m22.813s real 0m56.805s user 0m0.011s user 0m0.015s sys 0m5.076s sys 0m0.023s # See detailed table with results here: ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_default.txt ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_patched.txt # Hikey960 8x CPUs vs real unknown real 4m25.214s user unknown user 0m0.011s sys unknown sys 0m0.670s I did not manage to complete this test on "default Hikey960" kernel version. After 24 hours it was still running, therefore i had to cancel it. That is why real/user/sys are "unknown". This patch (of 3): Currently an allocation of the new vmap area is done over busy list iteration(complexity O(n)) until a suitable hole is found between two busy areas. Therefore each new allocation causes the list being grown. Due to over fragmented list and different permissive parameters an allocation can take a long time. For example on embedded devices it is milliseconds. This patch organizes the KVA memory layout into free areas of the 1-ULONG_MAX range. It uses an augment red-black tree that keeps blocks sorted by their offsets in pair with linked list keeping the free space in order of increasing addresses. Nodes are augmented with the size of the maximum available free block in its left or right sub-tree. Thus, that allows to take a decision and traversal toward the block that will fit and will have the lowest start address, i.e. it is sequential allocation. Allocation: to allocate a new block a search is done over the tree until a suitable lowest(left most) block is large enough to encompass: the requested size, alignment and vstart point. If the block is bigger than requested size - it is split. De-allocation: when a busy vmap area is freed it can either be merged or inserted to the tree. Red-black tree allows efficiently find a spot whereas a linked list provides a constant-time access to previous and next blocks to check if merging can be done. In case of merging of de-allocated memory chunk a large coalesced area is created. Complexity: ~O(log(N)) [urezki@gmail.com: v3] Link: http://lkml.kernel.org/r/20190402162531.10888-2-urezki@gmail.com [urezki@gmail.com: v4] Link: http://lkml.kernel.org/r/20190406183508.25273-2-urezki@gmail.com Link: http://lkml.kernel.org/r/20190321190327.11813-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Roman Gushchin Cc: Michal Hocko Cc: Matthew Wilcox Cc: Thomas Garnier Cc: Oleksiy Avramchenko Cc: Steven Rostedt Cc: Joel Fernandes Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds