- Feb 26, 2021
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Alexander Potapenko authored
Patch series "KFENCE: A low-overhead sampling-based memory safety error detector", v7. This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a low-overhead sampling-based memory safety error detector of heap use-after-free, invalid-free, and out-of-bounds access errors. This series enables KFENCE for the x86 and arm64 architectures, and adds KFENCE hooks to the SLAB and SLUB allocators. KFENCE is designed to be enabled in production kernels, and has near zero performance overhead. Compared to KASAN, KFENCE trades performance for precision. The main motivation behind KFENCE's design, is that with enough total uptime KFENCE will detect bugs in code paths not typically exercised by non-production test workloads. One way to quickly achieve a large enough total uptime is when the tool is deployed across a large fleet of machines. KFENCE objects each reside on a dedicated page, at either the left or right page boundaries. The pages to the left and right of the object page are "guard pages", whose attributes are changed to a protected state, and cause page faults on any attempted access to them. Such page faults are then intercepted by KFENCE, which handles the fault gracefully by reporting a memory access error. Guarded allocations are set up based on a sample interval (can be set via kfence.sample_interval). After expiration of the sample interval, the next allocation through the main allocator (SLAB or SLUB) returns a guarded allocation from the KFENCE object pool. At this point, the timer is reset, and the next allocation is set up after the expiration of the interval. To enable/disable a KFENCE allocation through the main allocator's fast-path without overhead, KFENCE relies on static branches via the static keys infrastructure. The static branch is toggled to redirect the allocation to KFENCE. The KFENCE memory pool is of fixed size, and if the pool is exhausted no further KFENCE allocations occur. The default config is conservative with only 255 objects, resulting in a pool size of 2 MiB (with 4 KiB pages). We have verified by running synthetic benchmarks (sysbench I/O, hackbench) and production server-workload benchmarks that a kernel with KFENCE (using sample intervals 100-500ms) is performance-neutral compared to a non-KFENCE baseline kernel. KFENCE is inspired by GWP-ASan [1], a userspace tool with similar properties. The name "KFENCE" is a homage to the Electric Fence Malloc Debugger [2]. For more details, see Documentation/dev-tools/kfence.rst added in the series -- also viewable here: https://raw.githubusercontent.com/google/kasan/kfence/Documentation/dev-tools/kfence.rst [1] http://llvm.org/docs/GwpAsan.html [2] https://linux.die.net/man/3/efence This patch (of 9): This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a low-overhead sampling-based memory safety error detector of heap use-after-free, invalid-free, and out-of-bounds access errors. KFENCE is designed to be enabled in production kernels, and has near zero performance overhead. Compared to KASAN, KFENCE trades performance for precision. The main motivation behind KFENCE's design, is that with enough total uptime KFENCE will detect bugs in code paths not typically exercised by non-production test workloads. One way to quickly achieve a large enough total uptime is when the tool is deployed across a large fleet of machines. KFENCE objects each reside on a dedicated page, at either the left or right page boundaries. The pages to the left and right of the object page are "guard pages", whose attributes are changed to a protected state, and cause page faults on any attempted access to them. Such page faults are then intercepted by KFENCE, which handles the fault gracefully by reporting a memory access error. To detect out-of-bounds writes to memory within the object's page itself, KFENCE also uses pattern-based redzones. The following figure illustrates the page layout: ---+-----------+-----------+-----------+-----------+-----------+--- | xxxxxxxxx | O : | xxxxxxxxx | : O | xxxxxxxxx | | xxxxxxxxx | B : | xxxxxxxxx | : B | xxxxxxxxx | | x GUARD x | J : RED- | x GUARD x | RED- : J | x GUARD x | | xxxxxxxxx | E : ZONE | xxxxxxxxx | ZONE : E | xxxxxxxxx | | xxxxxxxxx | C : | xxxxxxxxx | : C | xxxxxxxxx | | xxxxxxxxx | T : | xxxxxxxxx | : T | xxxxxxxxx | ---+-----------+-----------+-----------+-----------+-----------+--- Guarded allocations are set up based on a sample interval (can be set via kfence.sample_interval). After expiration of the sample interval, a guarded allocation from the KFENCE object pool is returned to the main allocator (SLAB or SLUB). At this point, the timer is reset, and the next allocation is set up after the expiration of the interval. To enable/disable a KFENCE allocation through the main allocator's fast-path without overhead, KFENCE relies on static branches via the static keys infrastructure. The static branch is toggled to redirect the allocation to KFENCE. To date, we have verified by running synthetic benchmarks (sysbench I/O, hackbench) that a kernel compiled with KFENCE is performance-neutral compared to the non-KFENCE baseline. For more details, see Documentation/dev-tools/kfence.rst (added later in the series). [elver@google.com: fix parameter description for kfence_object_start()] Link: https://lkml.kernel.org/r/20201106092149.GA2851373@elver.google.com [elver@google.com: avoid stalling work queue task without allocations] Link: https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com Link: https://lkml.kernel.org/r/20201110135320.3309507-1-elver@google.com [elver@google.com: fix potential deadlock due to wake_up()] Link: https://lkml.kernel.org/r/000000000000c0645805b7f982e4@google.com Link: https://lkml.kernel.org/r/20210104130749.1768991-1-elver@google.com [elver@google.com: add option to use KFENCE without static keys] Link: https://lkml.kernel.org/r/20210111091544.3287013-1-elver@google.com [elver@google.com: add missing copyright and description headers] Link: https://lkml.kernel.org/r/20210118092159.145934-1-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-2-elver@google.com Signed-off-by:
Marco Elver <elver@google.com> Signed-off-by:
Alexander Potapenko <glider@google.com> Reviewed-by:
Dmitry Vyukov <dvyukov@google.com> Reviewed-by:
SeongJae Park <sjpark@amazon.de> Co-developed-by:
Jann Horn <jannh@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Joern Engel <joern@purestorage.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Stephen Zhang authored
It is better to use __func__ instead of function name. Link: https://lkml.kernel.org/r/1611385587-4209-1-git-send-email-stephenzhangzsd@gmail.com Signed-off-by:
Stephen Zhang <stephenzhangzsd@gmail.com> Signed-off-by:
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Daniel Vetter authored
Now that my little helper has landed, use it more. On top of the existing check this also uses lockdep through the fs_reclaim annotations. [akpm@linux-foundation.org: include linux/sched/mm.h] Link: https://lkml.kernel.org/r/20210113135009.3606813-2-daniel.vetter@ffwll.ch Signed-off-by:
Daniel Vetter <daniel.vetter@intel.com> Signed-off-by:
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Daniel Vetter authored
Now that my little helper has landed, use it more. On top of the existing check this also uses lockdep through the fs_reclaim annotations. Link: https://lkml.kernel.org/r/20210113135009.3606813-1-daniel.vetter@ffwll.ch Signed-off-by:
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Guo Ren authored
The "If" was wrongly spelled as "It". Link: https://lkml.kernel.org/r/1608959036-91409-1-git-send-email-guoren@kernel.org Signed-off-by:
Guo Ren <guoren@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Steven Price <steven.price@arm.com> Signed-off-by:
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Miaohe Lin authored
It's recommended to use helper macro page_private() to access the private field of page. Use such helper to eliminate direct access. Link: https://lkml.kernel.org/r/20210203091857.20017-1-linmiaohe@huawei.com Signed-off-by:
Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by:
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Rokudo Yan authored
There exists multiple path may do zram compaction concurrently. 1. auto-compaction triggered during memory reclaim 2. userspace utils write zram<id>/compaction node So, multiple threads may call zs_shrinker_scan/zs_compact concurrently. But pages_compacted is a per zsmalloc pool variable and modification of the variable is not serialized(through under class->lock). There are two issues here: 1. the pages_compacted may not equal to total number of pages freed(due to concurrently add). 2. zs_shrinker_scan may not return the correct number of pages freed(issued by current shrinker). The fix is simple: 1. account the number of pages freed in zs_compact locally. 2. use actomic variable pages_compacted to accumulate total number. Link: https://lkml.kernel.org/r/20210202122235.26885-1-wu-yan@tcl.com Fixes: 860c707d ("zsmalloc: account the number of compacted pages") Signed-off-by:
Rokudo Yan <wu-yan@tcl.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Miaohe Lin authored
We always memset the zspage allocated via cache_alloc_zspage. So it's more convenient to use kmem_cache_zalloc in cache_alloc_zspage than caller do it manually. Link: https://lkml.kernel.org/r/20210114120032.25885-1-linmiaohe@huawei.com Signed-off-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by:
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Tian Tao authored
zpool driver adds a flag to indicate whether the zpool driver can enter an atomic context after mapping. This patch sets it true for z3fold and zbud. Link: https://lkml.kernel.org/r/1611035683-12732-3-git-send-email-tiantao6@hisilicon.com Signed-off-by:
Tian Tao <tiantao6@hisilicon.com> Reviewed-by:
Vitaly Wool <vitaly.wool@konsulko.com> Acked-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by:
Mike Galbraith <efault@gmx.de> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by:
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Tian Tao authored
Patch series "Fix the compatibility of zsmalloc and zswap". Patch #1 adds a flag to zpool, then zswap used to determine if zpool drivers such as zbud/z3fold/zsmalloc will enter an atomic context after mapping. The difference between zbud/z3fold and zsmalloc is that zsmalloc requires an atomic context that since its map function holds a preempt-disabled, but zbud/z3fold don't require an atomic context. So patch #2 sets flag sleep_mapped to true indicating that zbud/z3fold can sleep after mapping. zsmalloc didn't support sleep after mapping, so don't set that flag to true. This patch (of 2): Add a flag to zpool, named is "can_sleep_mapped", and have it set true for zbud/z3fold, not set this flag for zsmalloc, so its default value is false. Then zswap could go the current path if the flag is true; and if it's false, copy data from src to a temporary buffer, then unmap the handle, take the mutex, process the buffer instead of src to avoid sleeping function called from atomic context. [natechancellor@gmail.com: add return value in zswap_frontswap_load] Link: https://lkml.kernel.org/r/20210121214804.926843-1-natechancellor@gmail.com [tiantao6@hisilicon.com: fix potential memory leak] Link: https://lkml.kernel.org/r/1611538365-51811-1-git-send-email-tiantao6@hisilicon.com [colin.king@canonical.com: fix potential uninitialized pointer read on tmp] Link: https://lkml.kernel.org/r/20210128141728.639030-1-colin.king@canonical.com [tiantao6@hisilicon.com: fix variable 'entry' is uninitialized when used] Link: https://lkml.kernel.org/r/1611223030-58346-1-git-send-email-tiantao6@hisilicon.comLink: https://lkml.kernel.org/r/1611035683-12732-1-git-send-email-tiantao6@hisilicon.com Link: https://lkml.kernel.org/r/1611035683-12732-2-git-send-email-tiantao6@hisilicon.com Signed-off-by:
Nathan Chancellor <natechancellor@gmail.com> Signed-off-by:
Colin Ian King <colin.king@canonical.com> Reviewed-by:
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Randy Dunlap authored
Correct wording and change one duplicated word (it) to "it is". Link: https://lkml.kernel.org/r/20201221042848.13980-1-rdunlap@infradead.org Fixes: 0ab0abcf ("mm/zswap: refactor the get/put routines") Signed-off-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Weijie Yang <weijie.yang@samsung.com> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by:
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Miaohe Lin authored
For PMD-mapped page (usually THP), pvmw->pte is NULL. For PTE-mapped THP, pvmw->pte is mapped. But for HugeTLB pages, pvmw->pte is not mapped and set to the relevant page table entry. So in page_vma_mapped_walk_done(), we may do pte_unmap() for HugeTLB pte which is not mapped. Fix this by checking pvmw->page against PageHuge before trying to do pte_unmap(). Link: https://lkml.kernel.org/r/20210127093349.39081-1-linmiaohe@huawei.com Fixes: ace71a19 ("mm: introduce page_vma_mapped_walk()") Signed-off-by:
Hongxiang Lou <louhongxiang@huawei.com> Signed-off-by:
Sedat Dilek <sedat.dilek@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michel Lespinasse <walken@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Brian Geffon <bgeffon@google.com> Signed-off-by:
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Miaohe Lin authored
Since commit 746b18d4 ("mm: use refcounts for page_lock_anon_vma()"), page_lock_anon_vma() is renamed to page_get_anon_vma() and converted to return a refcount increased anon_vma. But it forgot to change the relevant comment. Link: https://lkml.kernel.org/r/20210203093215.31990-1-linmiaohe@huawei.com Signed-off-by:
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Miaohe Lin authored
page_mapcount_is_zero() calculates accurately how many mappings a hugepage has in order to check against 0 only. This is a waste of cpu time. We can do this via page_not_mapped() to save some possible atomic_read cycles. Remove the function page_mapcount_is_zero() as it's not used anymore and move page_not_mapped() above try_to_unmap() to avoid identifier undeclared compilation error. Link: https://lkml.kernel.org/r/20210130084904.35307-1-linmiaohe@huawei.com Signed-off-by:
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Miaohe Lin authored
Commit 21333b2b ("ksm: no debug in page_dup_rmap()") has reverted page_dup_rmap() to an inline atomic_inc of mapcount. So page_dup_rmap() does not call __page_check_anon_rmap() anymore. Link: https://lkml.kernel.org/r/20210128110209.50857-1-linmiaohe@huawei.com Signed-off-by:
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Miaohe Lin authored
Remove extra semicolon without any functional change intended. Link: https://lkml.kernel.org/r/20210127093425.39640-1-linmiaohe@huawei.com Signed-off-by:
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Miaohe Lin authored
commit 2b575eb6 ("mm: convert anon_vma->lock to a mutex") changed spinlock used to serialize access to vma list to mutex. And further, the commit 5a505085 ("mm/rmap: Convert the struct anon_vma::mutex to an rwsem") converted the mutex to an rwsem for solving scalability problem. So replace spinlock with rwsem to make comment uptodate. Link: https://lkml.kernel.org/r/20210123072459.25903-1-linmiaohe@huawei.com Signed-off-by:
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Miaohe Lin authored
There will be no vma satisfies addr < vm_end when find_vma() returns NULL. Thus it's meaningless to traverse the vma list below because we can't find any vma to count mlocked pages. Stop counting mlocked pages in this case to save some vma list traversal cycles. Link: https://lkml.kernel.org/r/20210204110705.17586-1-linmiaohe@huawei.com Signed-off-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
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David Hildenbrand authored
Right now, we only check against MAX_PHYSMEM_BITS - but turns out there are more restrictions of which memory we can actually hotplug, especially om arm64 or s390x once we support them: we might receive something like -E2BIG or -ERANGE from add_memory_driver_managed(), stopping device operation. So, check right when initializing the device which memory we can add, warning the user. Try only adding actually pluggable ranges: in the worst case, no memory provided by our device is pluggable. In the usual case, we expect all device memory to be pluggable, and in corner cases only some memory at the end of the device-managed memory region to not be pluggable. Link: https://lkml.kernel.org/r/1612149902-7867-5-git-send-email-anshuman.khandual@arm.com Signed-off-by:
Anshuman Khandual <anshuman.khandual@arm.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: teawater <teawaterz@linux.alibaba.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
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Anshuman Khandual authored
This overrides arch_get_mappabble_range() on s390 platform which will be used with recently added generic framework. It modifies the existing range check in vmem_add_mapping() using arch_get_mappable_range(). It also adds a VM_BUG_ON() check that would ensure that mhp_range_allowed() has already been called on the hotplug path. Link: https://lkml.kernel.org/r/1612149902-7867-4-git-send-email-anshuman.khandual@arm.com Signed-off-by:
Heiko Carstens <hca@linux.ibm.com> Reviewed-by:
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Anshuman Khandual authored
This overrides arch_get_mappable_range() on arm64 platform which will be used with recently added generic framework. It drops inside_linear_region() and subsequent check in arch_add_memory() which are no longer required. It also adds a VM_BUG_ON() check that would ensure that mhp_range_allowed() has already been called. Link: https://lkml.kernel.org/r/1612149902-7867-3-git-send-email-anshuman.khandual@arm.com Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: teawater <teawaterz@linux.alibaba.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by:
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Anshuman Khandual authored
Patch series "mm/memory_hotplug: Pre-validate the address range with platform", v5. This series adds a mechanism allowing platforms to weigh in and prevalidate incoming address range before proceeding further with the memory hotplug. This helps prevent potential platform errors for the given address range, down the hotplug call chain, which inevitably fails the hotplug itself. This mechanism was suggested by David Hildenbrand during another discussion with respect to a memory hotplug fix on arm64 platform. https://lore.kernel.org/linux-arm-kernel/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ This mechanism focuses on the addressibility aspect and not [sub] section alignment aspect. Hence check_hotplug_memory_range() and check_pfn_span() have been left unchanged. This patch (of 4): This introduces mhp_range_allowed() which can be called in various memory hotplug paths to prevalidate the address range which is being added, with the platform. Then mhp_range_allowed() calls mhp_get_pluggable_range() which provides applicable address range depending on whether linear mapping is required or not. For ranges that require linear mapping, it calls a new arch callback arch_get_mappable_range() which the platform can override. So the new callback, in turn provides the platform an opportunity to configure acceptable memory hotplug address ranges in case there are constraints. This mechanism will help prevent platform specific errors deep down during hotplug calls. This drops now redundant check_hotplug_memory_addressable() check in __add_pages() but instead adds a VM_BUG_ON() check which would ensure that the range has been validated with mhp_range_allowed() earlier in the call chain. Besides mhp_get_pluggable_range() also can be used by potential memory hotplug callers to avail the allowed physical range which would go through on a given platform. This does not really add any new range check in generic memory hotplug but instead compensates for lost checks in arch_add_memory() where applicable and check_hotplug_memory_addressable(), with unified mhp_range_allowed(). [akpm@linux-foundation.org: make pagemap_range() return -EINVAL when mhp_range_allowed() fails] Link: https://lkml.kernel.org/r/1612149902-7867-1-git-send-email-anshuman.khandual@arm.com Link: https://lkml.kernel.org/r/1612149902-7867-2-git-send-email-anshuman.khandual@arm.com Signed-off-by:
Oscar Salvador <osalvador@suse.de> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> # s390 Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: teawater <teawaterz@linux.alibaba.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by:
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David Hildenbrand authored
In commit 53cdc1cb ("drivers/base/memory.c: indicate all memory blocks as removable") we changed the output of the "removable" property of memory devices to return "1" if and only if the kernel supports memory offlining. Let's update documentation, stating that the interface is legacy. Also update documentation of the "state" property and "valid_zones" properties. Link: https://lkml.kernel.org/r/20210201181347.13262-3-david@redhat.com Signed-off-by:
Michal Hocko <mhocko@suse.com> Reviewed-by:
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David Hildenbrand authored
No need to store the value for each and every memory block, as we can easily query the value at runtime. Reshuffle the members to optimize the memory layout. Also, let's clarify what the interface once was used for and why it's legacy nowadays. "phys_device" was used on s390x in older versions of lsmem[2]/chmem[3], back when they were still part of s390x-tools. They were later replaced by the variants in linux-utils. For example, RHEL6 and RHEL7 contain lsmem/chmem from s390-utils. RHEL8 switched to versions from util-linux on s390x [4]. "phys_device" was added with sysfs support for memory hotplug in commit 3947be19 ("[PATCH] memory hotplug: sysfs and add/remove functions") in 2005. It always returned 0. s390x started returning something != 0 on some setups (if sclp.rzm is set by HW) in 2010 via commit 57b552ba ("memory hotplug/s390: set phys_device"). For s390x, it allowed for identifying which memory block devices belong to the same storage increment (RZM). Only if all memory block devices comprising a single storage increment were offline, the memory could actually be removed in the hypervisor. Since commit e5d709bb ("s390/memory hotplug: provide memory_block_size_bytes() function") in 2013 a memory block device spans at least one storage increment - which is why the interface isn't really helpful/used anymore (except by old lsmem/chmem tools). There were once RFC patches to make use of "phys_device" in ACPI context; however, the underlying problem could be solved using different interfaces [1]. [1] https://patchwork.kernel.org/patch/2163871/ [2] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/lsmem [3] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/chmem [4] https://bugzilla.redhat.com/show_bug.cgi?id=1504134 Link: https://lkml.kernel.org/r/20210201181347.13262-2-david@redhat.com Signed-off-by:
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Miaohe Lin authored
Commit 108bcc96 ("mm: add & use zone_end_pfn() and zone_spans_pfn()") introduced the helper zone_end_pfn() to calculate the zone end pfn. But update_pgdat_span() forgot to use it. Use this helper and rename local variable zone_end_pfn to end_pfn to avoid a naming conflict with the existing zone_end_pfn(). Link: https://lkml.kernel.org/r/20210127093211.37714-1-linmiaohe@huawei.com Signed-off-by:
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David Hildenbrand authored
Let's make "MEMHP_MERGE_RESOURCE" consistent with "MHP_NONE", "mhp_t" and "mhp_flags". As discussed recently [1], "mhp" is our internal acronym for memory hotplug now. [1] https://lore.kernel.org/linux-mm/c37de2d0-28a1-4f7d-f944-cfd7d81c334d@redhat.com/ Link: https://lkml.kernel.org/r/20210126115829.10909-1-david@redhat.com Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Reviewed-by:
Wei Liu <wei.liu@kernel.org> Reviewed-by:
Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by:
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Anshuman Khandual authored
This renames all 'memhp' instances to 'mhp' except for memhp_default_state for being a kernel command line option. This is just a clean up and should not cause a functional change. Let's make it consistent rater than mixing the two prefixes. In preparation for more users of the 'mhp' terminology. Link: https://lkml.kernel.org/r/1611554093-27316-1-git-send-email-anshuman.khandual@arm.com Signed-off-by:
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Dan Williams authored
Given 'struct dev_pagemap' spans both data pages and metadata pages be careful to consult the altmap if present to delineate metadata. In fact the pfn_first() helper already identifies the first valid data pfn, so export that helper for other code paths via pgmap_pfn_valid(). Other usage of get_dev_pagemap() are not a concern because those are operating on known data pfns having been looked up by get_user_pages(). I.e. metadata pfns are never user mapped. Link: https://lkml.kernel.org/r/161058501758.1840162.4239831989762604527.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 6100e34b ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages") Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Reported-by:
Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Qian Cai <cai@lca.pw> Signed-off-by:
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Dan Williams authored
While pfn_to_online_page() is able to determine pfn_valid() at subsection granularity it is not able to reliably determine if a given pfn is also online if the section is mixes ZONE_{NORMAL,MOVABLE} with ZONE_DEVICE. This means that pfn_to_online_page() may return invalid @page objects. For example with a memory map like: 100000000-1fbffffff : System RAM 142000000-143002e16 : Kernel code 143200000-143713fff : Kernel rodata 143800000-143b15b7f : Kernel data 144227000-144ffffff : Kernel bss 1fc000000-2fbffffff : Persistent Memory (legacy) 1fc000000-2fbffffff : namespace0.0 This command: echo 0x1fc000000 > /sys/devices/system/memory/soft_offline_page ...succeeds when it should fail. When it succeeds it touches an uninitialized page and may crash or cause other damage (see dissolve_free_huge_page()). While the memory map above is contrived via the memmap=ss!nn kernel command line option, the collision happens in practice on shipping platforms. The memory controller resources that decode spans of physical address space are a limited resource. One technique platform-firmware uses to conserve those resources is to share a decoder across 2 devices to keep the address range contiguous. Unfortunately the unit of operation of a decoder is 64MiB while the Linux section size is 128MiB. This results in situations where, without subsection hotplug memory mappings with different lifetimes collide into one object that can only express one lifetime. Update move_pfn_range_to_zone() to flag (SECTION_TAINT_ZONE_DEVICE) a section that mixes ZONE_DEVICE pfns with other online pfns. With SECTION_TAINT_ZONE_DEVICE to delineate, pfn_to_online_page() can fall back to a slow-path check for ZONE_DEVICE pfns in an online section. In the fast path online_section() for a full ZONE_DEVICE section returns false. Because the collision case is rare, and for simplicity, the SECTION_TAINT_ZONE_DEVICE flag is never cleared once set. [dan.j.williams@intel.com: fix CONFIG_ZONE_DEVICE=n build] Link: https://lkml.kernel.org/r/CAPcyv4iX+7LAgAeSqx7Zw-Zd=ZV9gBv8Bo7oTbwCOOqJoZ3+Yg@mail.gmail.com Link: https://lkml.kernel.org/r/161058500675.1840162.7887862152161279354.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: ba72b4c8 ("mm/sparsemem: support sub-section hotplug") Signed-off-by: -
Dan Williams authored
pfn_to_online_page is primarily used to filter out offline or fully uninitialized pages. pfn_valid resp. online_section_nr have a coarse per memory section granularity. If a section shared with a partially offline memory (e.g. part of ZONE_DEVICE) then pfn_to_online_page would lead to a false positive on some pfns. Fix this by adding pfn_section_valid check which is subsection aware. [mhocko@kernel.org: changelog rewrite] Link: https://lkml.kernel.org/r/161058500148.1840162.4365921007820501696.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: b13bc351 ("mm/hotplug: invalid PFNs from pfn_to_online_page()") Signed-off-by:
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Dan Williams authored
Patch series "mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE", v4. A pfn-walker that uses pfn_to_online_page() may inadvertently translate a pfn as online and in the page allocator, when it is offline managed by a ZONE_DEVICE mapping (details in Patch 3: ("mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions")). The 2 proposals under consideration are teach pfn_to_online_page() to be precise in the presence of mixed-zone sections, or teach the memory-add code to drop the System RAM associated with ZONE_DEVICE collisions. In order to not regress memory capacity by a few 10s to 100s of MiB the approach taken in this set is to add precision to pfn_to_online_page(). In the course of validating pfn_to_online_page() a couple other fixes fell out: 1/ soft_offline_page() fails to drop the reference taken in the madvise(..., MADV_SOFT_OFFLINE) case. 2/ memory_failure() uses get_dev_pagemap() to lookup ZONE_DEVICE pages, however that mapping may contain data pages and metadata raw pfns. Introduce pgmap_pfn_valid() to delineate the 2 types and fail the handling of raw metadata pfns. This patch (of 4); pfn_to_online_page() is already too large to be a macro or an inline function. In anticipation of further logic changes / growth, move it out of line. No functional change, just code movement. Link: https://lkml.kernel.org/r/161058499000.1840162.702316708443239771.stgit@dwillia2-desk3.amr.corp.intel.com Link: https://lkml.kernel.org/r/161058499608.1840162.10165648147615238793.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by:Michal Hocko <mhocko@kernel.org> Acked-by:
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Jiang Biao authored
Many 100us+ latencies have been deteceted in vmstat_shepherd() on CPX platform which has 208 logic cpus. And vmstat_shepherd is queued every second, which could make the case worse. Add schedule point in vmstat_shepherd() to erase the latency. Link: https://lkml.kernel.org/r/20210111035526.1511-1-benbjiang@tencent.com Signed-off-by:
Jiang Biao <benbjiang@tencent.com> Reported-by:
Bin Lai <robinlai@tencent.com> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by:
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Johannes Weiner authored
Byte-accounted items are used for slab object accounting at the cgroup level, because the objects in a slab page can belong to different cgroups. At the global level these items always change in multiples of whole slab pages. The vmstat code exploits this and stores these items as pages internally, which allows for more compact per-cpu data. This optimization isn't self-evident from the asserts and the division in the stat update functions. Provide the reader with some context. Link: https://lkml.kernel.org/r/20210202184411.118614-1-hannes@cmpxchg.org Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Johannes Weiner authored
On NOHZ, the periodic vmstat flushers on each CPU can go to sleep and won't wake up until stat changes are detected in the per-cpu deltas of the zone vmstat counters. In commit 75ef7184 ("mm, vmstat: add infrastructure for per-node vmstats") per-node counters were introduced, and subsequently most stats were moved from the zone to the node level. However, the node counters weren't added to the NOHZ wakeup detection. In theory this can cause per-cpu errors to remain in the user-reported stats indefinitely. In practice this only affects a handful of sub counters (file_mapped, dirty and writeback e.g.) because other page state changes at the node level likely involve a change at the zone level as well (alloc and free, lru ops). Also, nobody has complained. Fix it up for completeness: wake up vmstat refreshing on node changes. Also remove the BUILD_BUG_ONs that assert counter size; we haven't relied on it since we added sizeof() to the range calculation in commit 13c9aaf7 ("mm/vmstat.c: fix NUMA statistics updates"). Link: https://lkml.kernel.org/r/20210202184342.118513-1-hannes@cmpxchg.org Signed-off-by:
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Patrick Daly authored
Print the name of the CMA region for convenience. This is useful information to have when cma_alloc() fails. [pdaly@codeaurora.org: print the "count" variable] Link: https://lkml.kernel.org/r/20210209142414.12768-1-georgi.djakov@linaro.org Link: https://lkml.kernel.org/r/20210208115200.20286-1-georgi.djakov@linaro.org Signed-off-by:
Patrick Daly <pdaly@codeaurora.org> Signed-off-by:
Georgi Djakov <georgi.djakov@linaro.org> Acked-by:
Minchan Kim <minchan@kernel.org> Reviewed-by:
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David Hildenbrand authored
Let's count the number of CMA pages per zone and print them in /proc/zoneinfo. Having access to the total number of CMA pages per zone is helpful for debugging purposes to know where exactly the CMA pages ended up, and to figure out how many pages of a zone might behave differently, even after some of these pages might already have been allocated. As one example, CMA pages part of a kernel zone cannot be used for ordinary kernel allocations but instead behave more like ZONE_MOVABLE. For now, we are only able to get the global nr+free cma pages from /proc/meminfo and the free cma pages per zone from /proc/zoneinfo. Example after this patch when booting a 6 GiB QEMU VM with "hugetlb_cma=2G": # cat /proc/zoneinfo | grep cma cma 0 nr_free_cma 0 cma 0 nr_free_cma 0 cma 524288 nr_free_cma 493016 cma 0 cma 0 # cat /proc/meminfo | grep Cma CmaTotal: 2097152 kB CmaFree: 1972064 kB Note: We print even without CONFIG_CMA, just like "nr_free_cma"; this way, one can be sure when spotting "cma 0", that there are definetly no CMA pages located in a zone. [david@redhat.com: v2] Link: https://lkml.kernel.org/r/20210128164533.18566-1-david@redhat.com [david@redhat.com: v3] Link: https://lkml.kernel.org/r/20210129113451.22085-1-david@redhat.com Link: https://lkml.kernel.org/r/20210127101813.6370-3-david@redhat.com Signed-off-by:David Rientjes <rientjes@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by:
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David Hildenbrand authored
Right now, if activation fails, we might already have exposed some pages to the buddy for CMA use (although they will never get actually used by CMA), and some pages won't be exposed to the buddy at all. Let's check for "single zone" early and on error, don't expose any pages for CMA use - instead, expose them to the buddy available for any use. Simply call free_reserved_page() on every single page - easier than going via free_reserved_area(), converting back and forth between pfns and virt addresses. In addition, make sure to fixup totalcma_pages properly. Example: 6 GiB QEMU VM with "... hugetlb_cma=2G movablecore=20% ...": [ 0.006891] hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node [ 0.006893] cma: Reserved 2048 MiB at 0x0000000100000000 [ 0.006893] hugetlb_cma: reserved 2048 MiB on node 0 ... [ 0.175433] cma: CMA area hugetlb0 could not be activated Before this patch: # cat /proc/meminfo MemTotal: 5867348 kB MemFree: 5692808 kB MemAvailable: 5542516 kB ... CmaTotal: 2097152 kB CmaFree: 1884160 kB After this patch: # cat /proc/meminfo MemTotal: 6077308 kB MemFree: 5904208 kB MemAvailable: 5747968 kB ... CmaTotal: 0 kB CmaFree: 0 kB Note: cma_init_reserved_mem() makes sure that we always cover full pageblocks / MAX_ORDER - 1 pages. Link: https://lkml.kernel.org/r/20210127101813.6370-2-david@redhat.com Signed-off-by:
Zi Yan <ziy@nvidia.com> Reviewed-by:
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Roman Gushchin authored
Currently cma areas without a fixed base are allocated close to the end of the node. This placement is sub-optimal because of compaction: it brings pages into the cma area. In particular, it can bring in hot executable pages, even if there is a plenty of free memory on the machine. This results in cma allocation failures. Instead let's place cma areas close to the beginning of a node. In this case the compaction will help to free cma areas, resulting in better cma allocation success rates. If there is enough memory let's try to allocate bottom-up starting with 4GB to exclude any possible interference with DMA32. On smaller machines or in a case of a failure, stick with the old behavior. 16GB vm, 2GB cma area: With this patch: [ 0.000000] Command line: root=/dev/vda3 rootflags=subvol=/root systemd.unified_cgroup_hierarchy=1 enforcing=0 console=ttyS0,115200 hugetlb_cma=2G [ 0.002928] hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node [ 0.002930] cma: Reserved 2048 MiB at 0x0000000100000000 [ 0.002931] hugetlb_cma: reserved 2048 MiB on node 0 Without this patch: [ 0.000000] Command line: root=/dev/vda3 rootflags=subvol=/root systemd.unified_cgroup_hierarchy=1 enforcing=0 console=ttyS0,115200 hugetlb_cma=2G [ 0.002930] hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node [ 0.002933] cma: Reserved 2048 MiB at 0x00000003c0000000 [ 0.002934] hugetlb_cma: reserved 2048 MiB on node 0 v2: - switched to memblock_set_bottom_up(true), by Mike - start with 4GB, by Mike [guro@fb.com: whitespace fix, per Mike] Link: https://lkml.kernel.org/r/20201221170551.GB3428478@carbon.DHCP.thefacebook.com [guro@fb.com: fix 32-bit warnings] Link: https://lkml.kernel.org/r/20201223163537.GA4011967@carbon.DHCP.thefacebook.com [guro@fb.com: fix 32-bit systems] [akpm@linux-foundation.org: build fix] Link: https://lkml.kernel.org/r/20201217201214.3414100-1-guro@fb.com Signed-off-by:
Roman Gushchin <guro@fb.com> Reviewed-by:
Mike Rapoport <rppt@linux.ibm.com> Cc: Wonhyuk Yang <vvghjk1234@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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Rik van Riel authored
Hugh pointed out that the gma500 driver uses shmem pages, but needs to limit them to the DMA32 zone. Ensure the allocations resulting from the gfp_mask returned by limit_gfp_mask use the zone flags that were originally passed to shmem_getpage_gfp. Link: https://lkml.kernel.org/r/20210224121016.1314ed6d@imladris.surriel.com Signed-off-by:
Rik van Riel <riel@surriel.com> Suggested-by:
Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xu Yu <xuyu@linux.alibaba.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
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Rik van Riel authored
Currently if thp enabled=[madvise], mounting a tmpfs filesystem with huge=always and mmapping files from that tmpfs does not result in khugepaged collapsing those mappings, despite the mount flag indicating that it should. Fix that by breaking up the blocks of tests in hugepage_vma_check a little bit, and testing things in the correct order. Link: https://lkml.kernel.org/r/20201124194925.623931-4-riel@surriel.com Fixes: c2231020 ("mm: thp: register mm for khugepaged when merging vma for shmem") Signed-off-by:
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