- 05 Jun, 2020 9 commits
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Mike Rapoport authored
Patch series "mm: remove __ARCH_HAS_5LEVEL_HACK", v4. These patches convert several architectures to use page table folding and remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h and include/asm-generic/pgtable-nop4d-hack.h. With that we'll have a single and consistent way of dealing with page table folding instead of a mix of three existing options. The changes are mostly about mechanical replacement of pgd accessors with p4d ones and the addition of higher levels to page table traversals. This patch (of 14): h8300 is a nommu architecture and does not require fixup for upper layers of the page tables because it is already handled by the generic nommu implementation. Remove definition of __ARCH_USE_5LEVEL_HACK in arch/h8300/include/asm/pgtable.h Signed-off-by:
Mike Rapoport <rppt@linux.ibm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: James Morse <james.morse@arm.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> [openrisc] Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Joerg Roedel <joro@8bytes.org> Link: http://lkml.kernel.org/r/20200414153455.21744-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200414153455.21744-2-rppt@kernel.orgSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Feng Tang authored
This check was added by commit 82f71ae4 ("mm: catch memory commitment underflow") in 2014 to have a safety check for issues which have been fixed. And there has been few report caught by it, as described in its commit log: : This shouldn't happen any more - the previous two patches fixed : the committed_as underflow issues. But it was really found by Qian Cai when he used the LTP memory stress suite to test a RFC patchset, which tries to improve scalability of per-cpu counter 'vm_committed_as', by chosing a bigger 'batch' number for loose overcommit policies (OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS), while keeping current number for OVERCOMMIT_NEVER. With that patchset, when system firstly uses a loose policy, the 'vm_committed_as' count could be a big negative value, as its big 'batch' number allows a big deviation, then when the policy is changed to OVERCOMMIT_NEVER, the 'batch' will be decreased to a much smaller value, thus hits this WARN check. To mitigate this, one proposed solution is to queue work on all online CPUs to do a local sync for 'vm_committed_as' when changing policy to OVERCOMMIT_NEVER, plus some global syncing to garante the case won't be hit. But this solution is costy and slow, given this check hasn't shown real trouble or benefit, simply drop it from one hot path of MM. And perf stats does show some tiny saving for removing it. Reported-by:
Qian Cai <cai@lca.pw> Signed-off-by:
Feng Tang <feng.tang@intel.com> Signed-off-by:
Michal Hocko <mhocko@suse.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/20200603094804.GB89848@shbuild999.sh.intel.comSigned-off-by:
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Andrey Konovalov authored
This patch adds kcov_remote_start/stop() callbacks around the urb complete() callback that is executed in softirq context when dummy_hcd is in use. As the result, kcov can be used to collect coverage from those callbacks, which is used to facilitate coverage-guided fuzzing with syzkaller. Signed-off-by:
Andrey Konovalov <andreyknvl@google.com> Signed-off-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/4520671eeb604adbc2432c248b0c07fbaa5519ef.1585233617.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/2821d497ac1cdc0efb5e00df30271e4a67fc8009.1584655448.git.andreyknvl@google.comSigned-off-by:
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Andrey Konovalov authored
This change extends kcov remote coverage support to allow collecting coverage from soft interrupts in addition to kernel background threads. To collect coverage from code that is executed in softirq context, a part of that code has to be annotated with kcov_remote_start/stop() in a similar way as how it is done for global kernel background threads. Then the handle used for the annotations has to be passed to the KCOV_REMOTE_ENABLE ioctl. Internally this patch adjusts the __sanitizer_cov_trace_pc() compiler inserted callback to not bail out when called from softirq context. kcov_remote_start/stop() are updated to save/restore the current per task kcov state in a per-cpu area (in case the softirq came when the kernel was already collecting coverage in task context). Coverage from softirqs is collected into pre-allocated per-cpu areas, whose size is controlled by the new CONFIG_KCOV_IRQ_AREA_SIZE. [andreyknvl@google.com: turn current->kcov_softirq into unsigned int to fix objtool warning] Link: http://lkml.kernel.org/r/841c778aa3849c5cb8c3761f56b87ce653a88671.1585233617.git.andreyknvl@google.comSigned-off-by:
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Andrey Konovalov authored
Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find out whether the coverage is already being collected by the current task. Use t->kcov_mode for that instead. This doesn't change the overall behavior in any way, but serves as a preparation for the following softirq coverage collection support patch. Signed-off-by:
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Andrey Konovalov authored
Move t->kcov_sequence assignment before assigning t->kcov_mode for consistency. Signed-off-by:
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Andrey Konovalov authored
Every time kcov_start/stop() is called, t->kcov is also assigned, so move the assignment into the functions. Signed-off-by:
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Andrey Konovalov authored
If vmalloc() fails in kcov_remote_start() we'll access remote->kcov without holding kcov_remote_lock, so remote might potentially be freed at that point. Cache kcov pointer in a local variable. Signed-off-by:
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Andrey Konovalov authored
Patch series "kcov: collect coverage from usb soft interrupts", v4. This patchset extends kcov to allow collecting coverage from soft interrupts and then uses the new functionality to collect coverage from USB code. This has allowed to find at least one new HID bug [1], which was recently fixed by Alan [2]. [1] https://syzkaller.appspot.com/bug?extid=09ef48aa58261464b621 [2] https://patchwork.kernel.org/patch/11283319/ Any subsystem that uses softirqs (e.g. timers) can make use of this in the future. Looking at the recent syzbot reports, an obvious candidate is the networking subsystem [3, 4, 5 and many more]. [3] https://syzkaller.appspot.com/bug?extid=522ab502c69badc66ab7 [4] https://syzkaller.appspot.com/bug?extid=57f89d05946c53dbbb31 [5] https://syzkaller.appspot.com/bug?extid=df358e65d9c1b9d3f5f4 This pach (of 7): Previous commit left a lot of excessive debug messages, clean them up. Link; http://lkml.kernel.org/r/cover.1585233617.git.andreyknvl@google.com Link; http://lkml.kernel.org/r/ab5e2885ce674ba6e04368551e51eeb6a2c11baf.1585233617.git.andreyknvl@google.comSigned-off-by:
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- 04 Jun, 2020 31 commits
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Linus Torvalds authored
The atomisp_mrfld_power() function isn't actually ever called, because the two call-sites have commented out the use because it breaks on some platforms. That results in: drivers/staging/media/atomisp/pci/atomisp_v4l2.c:764:12: warning: ‘atomisp_mrfld_power’ defined but not used [-Wunused-function] 764 | static int atomisp_mrfld_power(struct atomisp_device *isp, bool enable) | ^~~~~~~~~~~~~~~~~~~ during the build. Rather than commenting out the use entirely, just disable it semantically instead (using a "0 &&" construct), leaving the call in place from a syntax standpoint, and avoiding the warning. I really don't want my builds to have any warnings that can then hide real issues. Signed-off-by: -
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediaLinus Torvalds authored
Pull media updates from Mauro Carvalho Chehab: - Media documentation is now split into admin-guide, driver-api and userspace-api books (a longstanding request from Jon); - The media Kconfig was reorganized, in order to make easier to select drivers and their dependencies; - The testing drivers now has a separate directory; - added a new driver for Rockchip Video Decoder IP; - The atomisp staging driver was resurrected. It is meant to work with 4 generations of cameras on Atom-based laptops, tablets and cell phones. So, it seems worth investing time to cleanup this driver and making it in good shape. - Added some V4L2 core ancillary routines to help with h264 codecs; - Added an ov2740 image sensor driver; - The si2157 gained support for Analog TV, which, in turn, added support for some cx231xx and cx23885 boards to also support analog standards; - Added some V4L2 controls (V4L2_CID_CAMERA_ORIENTATION and V4L2_CID_CAMERA_SENSOR_ROTATION) to help identifying where the camera is located at the device; - VIDIOC_ENUM_FMT was extended to support MC-centric devices; - Lots of drivers improvements and cleanups. * tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (503 commits) media: Documentation: media: Refer to mbus format documentation from CSI-2 docs media: s5k5baf: Replace zero-length array with flexible-array media: i2c: imx219: Drop <linux/clk-provider.h> and <linux/clkdev.h> media: i2c: Add ov2740 image sensor driver media: ov8856: Implement sensor module revision identification media: ov8856: Add devicetree support media: dt-bindings: ov8856: Document YAML bindings media: dvb-usb: Add Cinergy S2 PCIe Dual Port support media: dvbdev: Fix tuner->demod media controller link media: dt-bindings: phy: phy-rockchip-dphy-rx0: move rockchip dphy rx0 bindings out of staging media: staging: dt-bindings: phy-rockchip-dphy-rx0: remove non-used reg property media: atomisp: unify the version for isp2401 a0 and b0 versions media: atomisp: update TODO with the current data media: atomisp: adjust some code at sh_css that could be broken media: atomisp: don't produce errs for ignored IRQs media: atomisp: print IRQ when debugging media: atomisp: isp_mmu: don't use kmem_cache media: atomisp: add a notice about possible leak resources media: atomisp: disable the dynamic and reserved pools media: atomisp: turn on camera before setting it ...
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Linus Torvalds authored
Merge more updates from Andrew Morton: "More mm/ work, plenty more to come Subsystems affected by this patch series: slub, memcg, gup, kasan, pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs, thp, mmap, kconfig" * akpm: (131 commits) arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined riscv: support DEBUG_WX mm: add DEBUG_WX support drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid() powerpc/mm: drop platform defined pmd_mknotpresent() mm: thp: don't need to drain lru cache when splitting and mlocking THP hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs sparc32: register memory occupied by kernel as memblock.memory include/linux/memblock.h: fix minor typo and unclear comment mm, mempolicy: fix up gup usage in lookup_node tools/vm/page_owner_sort.c: filter out unneeded line mm: swap: memcg: fix memcg stats for huge pages mm: swap: fix vmstats for huge pages mm: vmscan: limit the range of LRU type balancing mm: vmscan: reclaim writepage is IO cost mm: vmscan: determine anon/file pressure balance at the reclaim root mm: balance LRU lists based on relative thrashing mm: only count actual rotations as LRU reclaim cost ...
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Zong Li authored
Extract DEBUG_WX to mm/Kconfig.debug for shared use. Change to use ARCH_HAS_DEBUG_WX instead of DEBUG_WX defined by arch port. Signed-off-by:
Zong Li <zong.li@sifive.com> Signed-off-by:
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Zong Li authored
Extract DEBUG_WX to mm/Kconfig.debug for shared use. Change to use ARCH_HAS_DEBUG_WX instead of DEBUG_WX defined by arch port. Signed-off-by:
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Zong Li authored
Support DEBUG_WX to check whether there are mapping with write and execute permission at the same time. [akpm@linux-foundation.org: replace macros with C] Signed-off-by:
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Zong Li authored
Patch series "Extract DEBUG_WX to shared use". Some architectures support DEBUG_WX function, it's verbatim from each others, so extract to mm/Kconfig.debug for shared use. PPC and ARM ports don't support generic page dumper yet, so we only refine x86 and arm64 port in this patch series. For RISC-V port, the DEBUG_WX support depends on other patches which be merged already: - RISC-V page table dumper - Support strict kernel memory permissions for security This patch (of 4): Some architectures support DEBUG_WX function, it's verbatim from each others. Extract to mm/Kconfig.debug for shared use. [akpm@linux-foundation.org: reword text, per Will Deacon & Zong Li] Link: http://lkml.kernel.org/r/20200427194245.oxRJKj3fn%25akpm@linux-foundation.org [zong.li@sifive.com: remove the specific name of arm64] Link: http://lkml.kernel.org/r/3a6a92ecedc54e1d0fc941398e63d504c2cd5611.1589178399.git.zong.li@sifive.com [zong.li@sifive.com: add MMU dependency for DEBUG_WX] Link: http://lkml.kernel.org/r/4a674ac7863ff39ca91847b10e51209771f99416.1589178399.git.zong.li@sifive.comSuggested-by:
Palmer Dabbelt <palmer@dabbelt.com> Signed-off-by:
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Scott Cheloha authored
Searching for a particular memory block by id is an O(n) operation because each memory block's underlying device is kept in an unsorted linked list on the subsystem bus. We can cut the lookup cost to O(log n) if we cache each memory block in an xarray. This time complexity improvement is significant on systems with many memory blocks. For example: 1. A 128GB POWER9 VM with 256MB memblocks has 512 blocks. With this change memory_dev_init() completes ~12ms faster and walk_memory_blocks() completes ~12ms faster. Before: [ 0.005042] memory_dev_init: adding memory blocks [ 0.021591] memory_dev_init: added memory blocks [ 0.022699] walk_memory_blocks: walking memory blocks [ 0.038730] walk_memory_blocks: walked memory blocks 0-511 After: [ 0.005057] memory_dev_init: adding memory blocks [ 0.009415] memory_dev_init: added memory blocks [ 0.010519] walk_memory_blocks: walking memory blocks [ 0.014135] walk_memory_blocks: walked memory blocks 0-511 2. A 256GB POWER9 LPAR with 256MB memblocks has 1024 blocks. With this change memory_dev_init() completes ~88ms faster and walk_memory_blocks() completes ~87ms faster. Before: [ 0.252246] memory_dev_init: adding memory blocks [ 0.395469] memory_dev_init: added memory blocks [ 0.409413] walk_memory_blocks: walking memory blocks [ 0.433028] walk_memory_blocks: walked memory blocks 0-511 [ 0.433094] walk_memory_blocks: walking memory blocks [ 0.500244] walk_memory_blocks: walked memory blocks 131072-131583 After: [ 0.245063] memory_dev_init: adding memory blocks [ 0.299539] memory_dev_init: added memory blocks [ 0.313609] walk_memory_blocks: walking memory blocks [ 0.315287] walk_memory_blocks: walked memory blocks 0-511 [ 0.315349] walk_memory_blocks: walking memory blocks [ 0.316988] walk_memory_blocks: walked memory blocks 131072-131583 3. A 32TB POWER9 LPAR with 256MB memblocks has 131072 blocks. With this change we complete memory_dev_init() ~37 minutes faster and walk_memory_blocks() at least ~30 minutes faster. The exact timing for walk_memory_blocks() is missing, though I observed that the soft lockups in walk_memory_blocks() disappeared with the change, suggesting that lower bound. Before: [ 13.703907] memory_dev_init: adding blocks [ 2287.406099] memory_dev_init: added all blocks [ 2347.494986] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 2527.625378] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 2707.761977] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 2887.899975] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3068.028318] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3248.158764] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3428.287296] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3608.425357] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3788.554572] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 3968.695071] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 [ 4148.823970] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160 After: [ 13.696898] memory_dev_init: adding blocks [ 15.660035] memory_dev_init: added all blocks (the walk_memory_blocks traces disappear) There should be no significant negative impact for machines with few memory blocks. A sparse xarray has a small footprint and an O(log n) lookup is negligibly slower than an O(n) lookup for only the smallest number of memory blocks. 1. A 16GB x86 machine with 128MB memblocks has 132 blocks. With this change memory_dev_init() completes ~300us faster and walk_memory_blocks() completes no faster or slower. The improvement is pretty close to noise. Before: [ 0.224752] memory_dev_init: adding memory blocks [ 0.227116] memory_dev_init: added memory blocks [ 0.227183] walk_memory_blocks: walking memory blocks [ 0.227183] walk_memory_blocks: walked memory blocks 0-131 After: [ 0.224911] memory_dev_init: adding memory blocks [ 0.226935] memory_dev_init: added memory blocks [ 0.227089] walk_memory_blocks: walking memory blocks [ 0.227089] walk_memory_blocks: walked memory blocks 0-131 [david@redhat.com: document the locking] Link: http://lkml.kernel.org/r/bc21eec6-7251-4c91-2f57-9a0671f8d414@redhat.comSigned-off-by:
Scott Cheloha <cheloha@linux.ibm.com> Signed-off-by:
David Hildenbrand <david@redhat.com> Acked-by:
Nathan Lynch <nathanl@linux.ibm.com> Acked-by:
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Anshuman Khandual authored
pmd_present() is expected to test positive after pmdp_mknotpresent() as the PMD entry still points to a valid huge page in memory. pmdp_mknotpresent() implies that given PMD entry is just invalidated from MMU perspective while still holding on to pmd_page() referred valid huge page thus also clearing pmd_present() test. This creates the following situation which is counter intuitive. [pmd_present(pmd_mknotpresent(pmd)) = true] This renames pmd_mknotpresent() as pmd_mkinvalid() reflecting the helper's functionality more accurately while changing the above mentioned situation as follows. This does not create any functional change. [pmd_present(pmd_mkinvalid(pmd)) = true] This is not applicable for platforms that define own pmdp_invalidate() via __HAVE_ARCH_PMDP_INVALIDATE. Suggestion for renaming came during a previous discussion here. https://patchwork.kernel.org/patch/11019637/ [anshuman.khandual@arm.com: change pmd_mknotvalid() to pmd_mkinvalid() per Will] Link: http://lkml.kernel.org/r/1587520326-10099-3-git-send-email-anshuman.khandual@arm.comSuggested-by:
Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
Will Deacon <will@kernel.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Link: http://lkml.kernel.org/r/1584680057-13753-3-git-send-email-anshuman.khandual@arm.comSigned-off-by:
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Anshuman Khandual authored
Patch series "mm/thp: Rename pmd_mknotpresent() as pmd_mknotvalid()", v2. This series renames pmd_mknotpresent() as pmd_mknotvalid(). Before that it drops an existing pmd_mknotpresent() definition from powerpc platform which was never required as it defines it's pmdp_invalidate() through subscribing __HAVE_ARCH_PMDP_INVALIDATE. This does not create any functional change. This rename was suggested by Catalin during a previous discussion while we were trying to change the THP helpers on arm64 platform for migration. https://patchwork.kernel.org/patch/11019637/ This patch (of 2): Platform needs to define pmd_mknotpresent() for generic pmdp_invalidate() only when __HAVE_ARCH_PMDP_INVALIDATE is not subscribed. Otherwise platform specific pmd_mknotpresent() is not required. Hence just drop it. Signed-off-by:
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Yang Shi authored
Since commit 8f182270 ("mm/swap.c: flush lru pvecs on compound page arrival") THP would not stay in pagevec anymore. So the optimization made by commit d9654322 ("thp: increase split_huge_page() success rate") doesn't make sense anymore, which tries to unpin munlocked THPs from pagevec by draining pagevec. Draining lru cache before isolating THP in mlock path is also unnecessary. b676b293 ("mm, thp: fix mapped pages avoiding unevictable list on mlock") added it and 9a73f61b ("thp, mlock: do not mlock PTE-mapped file huge pages") accidentally carried it over after the above optimization went in. Signed-off-by:
Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by:
Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Link: http://lkml.kernel.org/r/1585946493-7531-1-git-send-email-yang.shi@linux.alibaba.comSigned-off-by:
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Shijie Hu authored
In a 32-bit program, running on arm64 architecture. When the address space below mmap base is completely exhausted, shmat() for huge pages will return ENOMEM, but shmat() for normal pages can still success on no-legacy mode. This seems not fair. For normal pages, the calling trace of get_unmapped_area() is: => mm->get_unmapped_area() if on legacy mode, => arch_get_unmapped_area() => vm_unmapped_area() if on no-legacy mode, => arch_get_unmapped_area_topdown() => vm_unmapped_area() For huge pages, the calling trace of get_unmapped_area() is: => file->f_op->get_unmapped_area() => hugetlb_get_unmapped_area() => vm_unmapped_area() To solve this issue, we only need to make hugetlb_get_unmapped_area() take the same way as mm->get_unmapped_area(). Add *bottomup() and *topdown() for hugetlbfs, and check current mm->get_unmapped_area() to decide which one to use. If mm->get_unmapped_area is equal to arch_get_unmapped_area_topdown(), hugetlb_get_unmapped_area() calls topdown routine, otherwise calls bottomup routine. Reported-by:
kbuild test robot <lkp@intel.com> Signed-off-by:
Shijie Hu <hushijie3@huawei.com> Signed-off-by:
Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
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Mike Rapoport authored
sparc32 never registered the memory occupied by the kernel image with memblock_add() and it only reserved this memory with meblock_reserve(). With openbios as system firmware, the memory occupied by the kernel is reserved in openbios and removed from mem.available. The prom setup code in the kernel uses mem.available to set up the memory banks and essentially there is a hole for the memory occupied by the kernel image. Later in bootmem_init() this memory is memblock_reserve()d. Up until recently, memmap initialization would call __init_single_page() for the pages in that hole, the free_low_memory_core_early() would mark them as reserved and everything would be Ok. After the change in memmap initialization introduced by the commit "mm: memmap_init: iterate over memblock regions rather that check each PFN", the hole is skipped and the page structs for it are not initialized. And when they are passed from memblock to page allocator as reserved, the latter gets confused. Simply registering the memory occupied by the kernel with memblock_add() resolves this issue. Tested on qemu-system-sparc with Debian Etch [1] userspace. [1] https://people.debian.org/~aurel32/qemu/sparc/debian_etch_sparc_small.qcow2Signed-off-by:
David S. Miller <davem@davemloft.net> Cc: Guenter Roeck <linux@roeck-us.net> Link: https://lkml.kernel.org/r/20200517000050.GA87467@roeck-us.nlllllet/Signed-off-by:
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chenqiwu authored
Fix a minor typo "usabe->usable" for the current discription of member variable "memory" in struct memblock. BTW, I think it's unclear the member variable "base" in struct memblock_type is currently described as the physical address of memory region, change it to base address of the region is clearer since the variable is decorated as phys_addr_t. Signed-off-by:
chenqiwu <chenqiwu@xiaomi.com> Signed-off-by:
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Michal Hocko authored
ba841078 ("mm/mempolicy: Allow lookup_node() to handle fatal signal") has added a special casing for 0 return value because that was a possible gup return value when interrupted by fatal signal. This has been fixed by ae46d2aa ("mm/gup: Let __get_user_pages_locked() return -EINTR for fatal signal") in the mean time so ba841078 can be reverted. This patch however doesn't go all the way to revert it because the check for 0 is wrong and confusing here. Firstly it is inherently unsafe to access the page when get_user_pages_locked returns 0 (aka no page returned). Fortunatelly this will not happen because get_user_pages_locked will not return 0 when nr_pages > 0 unless FOLL_NOWAIT is specified which is not the case here. Document this potential error code in gup code while we are at it. Signed-off-by:
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Changhee Han authored
To see a sorted result from page_owner, there must be a tiresome preprocessing step before running page_owner_sort. This patch simply filters out lines which start with "PFN" while reading the page owner report. Signed-off-by:
Changhee Han <ch0.han@lge.com> Signed-off-by:
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Shakeel Butt authored
The commit 2262185c ("mm: per-cgroup memory reclaim stats") added PGLAZYFREE, PGACTIVATE & PGDEACTIVATE stats for cgroups but missed couple of places and PGLAZYFREE missed huge page handling. Fix that. Also for PGLAZYFREE use the irq-unsafe function to update as the irq is already disabled. Fixes: 2262185c ("mm: per-cgroup memory reclaim stats") Signed-off-by:
Shakeel Butt <shakeelb@google.com> Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Link: http://lkml.kernel.org/r/20200527182947.251343-1-shakeelb@google.comSigned-off-by:
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Shakeel Butt authored
Many of the callbacks called by pagevec_lru_move_fn() does not correctly update the vmstats for huge pages. Fix that. Also __pagevec_lru_add_fn() use the irq-unsafe alternative to update the stat as the irqs are already disabled. Signed-off-by:
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Johannes Weiner authored
When LRU cost only shows up on one list, we abruptly stop scanning that list altogether. That's an extreme reaction: by the time the other list starts thrashing and the pendulum swings back, we may have no recent age information on the first list anymore, and we could have significant latencies until the scanner has caught up. Soften this change in the feedback system by ensuring that no list receives less than a third of overall pressure, and only distribute the other 66% according to LRU cost. This ensures that we maintain a minimum rate of aging on the entire workingset while it's being pressured, while still allowing a generous rate of convergence when the relative sizes of the lists need to adjust. Signed-off-by:
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Johannes Weiner authored
The VM tries to balance reclaim pressure between anon and file so as to reduce the amount of IO incurred due to the memory shortage. It already counts refaults and swapins, but in addition it should also count writepage calls during reclaim. For swap, this is obvious: it's IO that wouldn't have occurred if the anonymous memory hadn't been under memory pressure. From a relative balancing point of view this makes sense as well: even if anon is cold and reclaimable, a cache that isn't thrashing may have equally cold pages that don't require IO to reclaim. For file writeback, it's trickier: some of the reclaim writepage IO would have likely occurred anyway due to dirty expiration. But not all of it - premature writeback reduces batching and generates additional writes. Since the flushers are already woken up by the time the VM starts writing cache pages one by one, let's assume that we'e likely causing writes that wouldn't have happened without memory pressure. In addition, the per-page cost of IO would have probably been much cheaper if written in larger batches from the flusher thread rather than the single-page-writes from kswapd. For our purposes - getting the trend right to accelerate convergence on a stable state that doesn't require paging at all - this is sufficiently accurate. If we later wanted to optimize for sustained thrashing, we can still refine the measurements. Count all writepage calls from kswapd as IO cost toward the LRU that the page belongs to. Why do this dynamically? Don't we know in advance that anon pages require IO to reclaim, and so could build in a static bias? First, scanning is not the same as reclaiming. If all the anon pages are referenced, we may not swap for a while just because we're scanning the anon list. During this time, however, it's important that we age anonymous memory and the page cache at the same rate so that their hot-cold gradients are comparable. Everything else being equal, we still want to reclaim the coldest memory overall. Second, we keep copies in swap unless the page changes. If there is swap-backed data that's mostly read (tmpfs file) and has been swapped out before, we can reclaim it without incurring additional IO. Signed-off-by:
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Johannes Weiner authored
We split the LRU lists into anon and file, and we rebalance the scan pressure between them when one of them begins thrashing: if the file cache experiences workingset refaults, we increase the pressure on anonymous pages; if the workload is stalled on swapins, we increase the pressure on the file cache instead. With cgroups and their nested LRU lists, we currently don't do this correctly. While recursive cgroup reclaim establishes a relative LRU order among the pages of all involved cgroups, LRU pressure balancing is done on an individual cgroup LRU level. As a result, when one cgroup is thrashing on the filesystem cache while a sibling may have cold anonymous pages, pressure doesn't get equalized between them. This patch moves LRU balancing decision to the root of reclaim - the same level where the LRU order is established. It does this by tracking LRU cost recursively, so that every level of the cgroup tree knows the aggregate LRU cost of all memory within its domain. When the page scanner calculates the scan balance for any given individual cgroup's LRU list, it uses the values from the ancestor cgroup that initiated the reclaim cycle. If one sibling is then thrashing on the cache, it will tip the pressure balance inside its ancestors, and the next hierarchical reclaim iteration will go more after the anon pages in the tree. Signed-off-by:
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Johannes Weiner authored
Since the LRUs were split into anon and file lists, the VM has been balancing between page cache and anonymous pages based on per-list ratios of scanned vs. rotated pages. In most cases that tips page reclaim towards the list that is easier to reclaim and has the fewest actively used pages, but there are a few problems with it: 1. Refaults and LRU rotations are weighted the same way, even though one costs IO and the other costs a bit of CPU. 2. The less we scan an LRU list based on already observed rotations, the more we increase the sampling interval for new references, and rotations become even more likely on that list. This can enter a death spiral in which we stop looking at one list completely until the other one is all but annihilated by page reclaim. Since commit a528910e ("mm: thrash detection-based file cache sizing") we have refault detection for the page cache. Along with swapin events, they are good indicators of when the file or anon list, respectively, is too small for its workingset and needs to grow. For example, if the page cache is thrashing, the cache pages need more time in memory, while there may be colder pages on the anonymous list. Likewise, if swapped pages are faulting back in, it indicates that we reclaim anonymous pages too aggressively and should back off. Replace LRU rotations with refaults and swapins as the basis for relative reclaim cost of the two LRUs. This will have the VM target list balances that incur the least amount of IO on aggregate. Signed-off-by:
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Johannes Weiner authored
When shrinking the active file list we rotate referenced pages only when they're in an executable mapping. The others get deactivated. When it comes to balancing scan pressure, though, we count all referenced pages as rotated, even the deactivated ones. Yet they do not carry the same cost to the system: the deactivated page *might* refault later on, but the deactivation is tangible progress toward freeing pages; rotations on the other hand cost time and effort without getting any closer to freeing memory. Don't treat both events as equal. The following patch will hook up LRU balancing to cache and anon refaults, which are a much more concrete cost signal for reclaiming one list over the other. Thus, remove the maybe-IO cost bias from page references, and only note the CPU cost for actual rotations that prevent the pages from getting reclaimed. Signed-off-by:
Minchan Kim <minchan@kernel.org> Acked-by:
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Johannes Weiner authored
Operations like MADV_FREE, FADV_DONTNEED etc. currently move any affected active pages to the inactive list to accelerate their reclaim (good) but also steer page reclaim toward that LRU type, or away from the other (bad). The reason why this is undesirable is that such operations are not part of the regular page aging cycle, and rather a fluke that doesn't say much about the remaining pages on that list; they might all be in heavy use, and once the chunk of easy victims has been purged, the VM continues to apply elevated pressure on those remaining hot pages. The other LRU, meanwhile, might have easily reclaimable pages, and there was never a need to steer away from it in the first place. As the previous patch outlined, we should focus on recording actually observed cost to steer the balance rather than speculating about the potential value of one LRU list over the other. In that spirit, leave explicitely deactivated pages to the LRU algorithm to pick up, and let rotations decide which list is the easiest to reclaim. [cai@lca.pw: fix set-but-not-used warning] Link: http://lkml.kernel.org/r/20200522133335.GA624@Qians-MacBook-Air.localSigned-off-by:
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Johannes Weiner authored
Currently, scan pressure between the anon and file LRU lists is balanced based on a mixture of reclaim efficiency and a somewhat vague notion of "value" of having certain pages in memory over others. That concept of value is problematic, because it has caused us to count any event that remotely makes one LRU list more or less preferrable for reclaim, even when these events are not directly comparable and impose very different costs on the system. One example is referenced file pages that we still deactivate and referenced anonymous pages that we actually rotate back to the head of the list. There is also conceptual overlap with the LRU algorithm itself. By rotating recently used pages instead of reclaiming them, the algorithm already biases the applied scan pressure based on page value. Thus, when rebalancing scan pressure due to rotations, we should think of reclaim cost, and leave assessing the page value to the LRU algorithm. Lastly, considering both value-increasing as well as value-decreasing events can sometimes cause the same type of event to be counted twice, i.e. how rotating a page increases the LRU value, while reclaiming it succesfully decreases the value. In itself this will balance out fine, but it quietly skews the impact of events that are only recorded once. The abstract metric of "value", the murky relationship with the LRU algorithm, and accounting both negative and positive events make the current pressure balancing model hard to reason about and modify. This patch switches to a balancing model of accounting the concrete, actually observed cost of reclaiming one LRU over another. For now, that cost includes pages that are scanned but rotated back to the list head. Subsequent patches will add consideration for IO caused by refaulting of recently evicted pages. Replace struct zone_reclaim_stat with two cost counters in the lruvec, and make everything that affects cost go through a new lru_note_cost() function. Signed-off-by:
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Johannes Weiner authored
When we calculate the relative scan pressure between the anon and file LRU lists, we have to assume that reclaim_stat can contain zeroes. To avoid div0 crashes, we add 1 to all denominators like so: anon_prio = swappiness; file_prio = 200 - anon_prio; [...] /* * The amount of pressure on anon vs file pages is inversely * proportional to the fraction of recently scanned pages on * each list that were recently referenced and in active use. */ ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1); ap /= reclaim_stat->recent_rotated[0] + 1; fp = file_prio * (reclaim_stat->recent_scanned[1] + 1); fp /= reclaim_stat->recent_rotated[1] + 1; spin_unlock_irq(&pgdat->lru_lock); fraction[0] = ap; fraction[1] = fp; denominator = ap + fp + 1; While reclaim_stat can contain 0, it's not actually possible for ap + fp to be 0. One of anon_prio or file_prio could be zero, but they must still add up to 200. And the reclaim_stat fraction, due to the +1 in there, is always at least 1. So if one of the two numerators is 0, the other one can't be. ap + fp is always at least 1. Drop the + 1. Signed-off-by: -
Johannes Weiner authored
When the splitlru patches divided page cache and swap-backed pages into separate LRU lists, the pressure balance between the lists was biased to account for the fact that streaming IO can cause memory pressure with a flood of pages that are used only once. New page cache additions would tip the balance toward the file LRU, and repeat access would neutralize that bias again. This ensured that page reclaim would always go for used-once cache first. Since e9868505 ("mm,vmscan: only evict file pages when we have plenty"), page reclaim generally skips over swap-backed memory entirely as long as there is used-once cache present, and will apply the LRU balancing when only repeatedly accessed cache pages are left - at which point the previous use-once bias will have been neutralized. This makes the use-once cache balancing bias unnecessary. Signed-off-by:
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Johannes Weiner authored
We activate cache refaults with reuse distances in pages smaller than the size of the total cache. This allows new pages with competitive access frequencies to establish themselves, as well as challenge and potentially displace pages on the active list that have gone cold. However, that assumes that active cache can only replace other active cache in a competition for the hottest memory. This is not a great default assumption. The page cache might be thrashing while there are enough completely cold and unused anonymous pages sitting around that we'd only have to write to swap once to stop all IO from the cache. Activate cache refaults when their reuse distance in pages is smaller than the total userspace workingset, including anonymous pages. Reclaim can still decide how to balance pressure among the two LRUs depending on the IO situation. Rotational drives will prefer avoiding random IO from swap and go harder after cache. But fundamentally, hot cache should be able to compete with anon pages for a place in RAM. Signed-off-by:
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Johannes Weiner authored
They're the same function, and for the purpose of all callers they are equivalent to lru_cache_add(). [akpm@linux-foundation.org: fix it for local_lock changes] Signed-off-by:
Rik van Riel <riel@surriel.com> Acked-by:
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Johannes Weiner authored
With the advent of fast random IO devices (SSDs, PMEM) and in-memory swap devices such as zswap, it's possible for swap to be much faster than filesystems, and for swapping to be preferable over thrashing filesystem caches. Allow setting swappiness - which defines the rough relative IO cost of cache misses between page cache and swap-backed pages - to reflect such situations by making the swap-preferred range configurable. Signed-off-by:
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Johannes Weiner authored
Having statistics on pages scanned and pages reclaimed for both anon and file pages makes it easier to evaluate changes to LRU balancing. While at it, clean up the stat-keeping mess for isolation, putback, reclaim stats etc. a bit: first the physical LRU operation (isolation and putback), followed by vmstats, reclaim_stats, and then vm events. Signed-off-by:
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