- 06 Mar, 2019 40 commits
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Joel Fernandes (Google) authored
Add tests to verify sealing memfds with the F_SEAL_FUTURE_WRITE works as expected. Link: http://lkml.kernel.org/r/20190112203816.85534-3-joel@joelfernandes.orgSigned-off-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by:
Shuah Khan <shuah@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Joel Fernandes (Google) authored
Android uses ashmem for sharing memory regions. We are looking forward to migrating all usecases of ashmem to memfd so that we can possibly remove the ashmem driver in the future from staging while also benefiting from using memfd and contributing to it. Note staging drivers are also not ABI and generally can be removed at anytime. One of the main usecases Android has is the ability to create a region and mmap it as writeable, then add protection against making any "future" writes while keeping the existing already mmap'ed writeable-region active. This allows us to implement a usecase where receivers of the shared memory buffer can get a read-only view, while the sender continues to write to the buffer. See CursorWindow documentation in Android for more details: https://developer.android.com/reference/android/database/CursorWindow This usecase cannot be implemented with the existing F_SEAL_WRITE seal. To support the usecase, this patch adds a new F_SEAL_FUTURE_WRITE seal which prevents any future mmap and write syscalls from succeeding while keeping the existing mmap active. A better way to do F_SEAL_FUTURE_WRITE seal was discussed [1] last week where we don't need to modify core VFS structures to get the same behavior of the seal. This solves several side-effects pointed by Andy. self-tests are provided in later patch to verify the expected semantics. [1] https://lore.kernel.org/lkml/20181111173650.GA256781@google.com/ Thanks a lot to Andy for suggestions to improve code. Link: http://lkml.kernel.org/r/20190112203816.85534-2-joel@joelfernandes.orgSigned-off-by:
John Stultz <john.stultz@linaro.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
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Aneesh Kumar K.V authored
THP pages can get split during different code paths. An incremented reference count does imply we will not split the compound page. But the pmd entry can be converted to level 4 pte entries. Keep the code simpler by allowing large IOMMU page size only if the guest ram is backed by hugetlb pages. Link: http://lkml.kernel.org/r/20190114095438.32470-6-aneesh.kumar@linux.ibm.comSigned-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by:
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Aneesh Kumar K.V authored
The current code doesn't do page migration if the page allocated is a compound page. With HugeTLB migration support, we can end up allocating hugetlb pages from CMA region. Also, THP pages can be allocated from CMA region. This patch updates the code to handle compound pages correctly. The patch also switches to a single get_user_pages with the right count, instead of doing one get_user_pages per page. That avoids reading page table multiple times. This is done by using get_user_pages_longterm, because that also takes care of DAX backed pages. DAX pages lifetime is dictated by file system rules and as such, we need to make sure that we free these pages on operations like truncate and punch hole. If we have long term pin on these pages, which are mostly return to userspace with elevated page count, the entity holding the long term pin may not be aware of the fact that file got truncated and the file system blocks possibly got reused. That can result in corruption. The patch also converts the hpas member of mm_iommu_table_group_mem_t to a union. We use the same storage location to store pointers to struct page. We cannot update all the code path use struct page *, because we access hpas in real mode and we can't do that struct page * to pfn conversion in real mode. [aneesh.kumar@linux.ibm.com: address review feedback, update changelog] Link: http://lkml.kernel.org/r/20190227144736.5872-4-aneesh.kumar@linux.ibm.com Link: http://lkml.kernel.org/r/20190114095438.32470-5-aneesh.kumar@linux.ibm.comSigned-off-by:
Michael Ellerman <mpe@ellerman.id.au> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by:
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Aneesh Kumar K.V authored
This patch updates get_user_pages_longterm to migrate pages allocated out of CMA region. This makes sure that we don't keep non-movable pages (due to page reference count) in the CMA area. This will be used by ppc64 in a later patch to avoid pinning pages in the CMA region. ppc64 uses CMA region for allocation of the hardware page table (hash page table) and not able to migrate pages out of CMA region results in page table allocation failures. One case where we hit this easy is when a guest using a VFIO passthrough device. VFIO locks all the guest's memory and if the guest memory is backed by CMA region, it becomes unmovable resulting in fragmenting the CMA and possibly preventing other guests from allocation a large enough hash page table. NOTE: We allocate the new page without using __GFP_THISNODE Link: http://lkml.kernel.org/r/20190114095438.32470-3-aneesh.kumar@linux.ibm.comSigned-off-by:
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Aneesh Kumar K.V authored
Patch series "mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region", v8. ppc64 uses the CMA area for the allocation of guest page table (hash page table). We won't be able to start guest if we fail to allocate hash page table. We have observed hash table allocation failure because we failed to migrate pages out of CMA region because they were pinned. This happen when we are using VFIO. VFIO on ppc64 pins the entire guest RAM. If the guest RAM pages get allocated out of CMA region, we won't be able to migrate those pages. The pages are also pinned for the lifetime of the guest. Currently we support migration of non-compound pages. With THP and with the addition of hugetlb migration we can end up allocating compound pages from CMA region. This patch series add support for migrating compound pages. This patch (of 4): Add PF_MEMALLOC_NOCMA which make sure any allocation in that context is marked non-movable and hence cannot be satisfied by CMA region. This is useful with get_user_pages_longterm where we want to take a page pin by migrating pages from CMA region. Marking the section PF_MEMALLOC_NOCMA ensures that we avoid unnecessary page migration later. Link: http://lkml.kernel.org/r/20190114095438.32470-2-aneesh.kumar@linux.ibm.comSigned-off-by:
Andrea Arcangeli <aarcange@redhat.com> Reviewed-by:
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David Hildenbrand authored
The usage of PG_reserved and how PG_reserved pages are to be treated is buried deep down in different parts of the kernel. Let's shine some light onto these details by documenting current users and expected behavior. Especially, clarify on the "Some of them might not even exist" case. These are physical memory gaps that will never be dumped as they are not marked as IORESOURCE_SYSRAM. PG_reserved does in general not hinder anybody from dumping or swapping. In some cases, these pages will not be stored in the hibernation image. Link: http://lkml.kernel.org/r/20190114125903.24845-10-david@redhat.comSigned-off-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
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David Hildenbrand authored
In the old days, remap_pfn_range() required pages to be marked as PG_reserved, so they would e.g. never get swapped out. This was required for special mappings. Nowadays, this is fully handled via the VMA (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP inside remap_pfn_range() to be precise). PG_reserved is no longer required but only a relic from the past. So only architecture specific MM handling might require it (e.g. to detect them as MMIO pages). As there are no architecture specific checks for PageReserved() apart from MCA handling in ia64code, this can go. Use simple vzalloc()/vfree() instead. Note that before calling vzalloc(), size has already been aligned to PAGE_SIZE, no need to align again. Link: http://lkml.kernel.org/r/20190114125903.24845-9-david@redhat.comSigned-off-by:
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David Hildenbrand authored
The crashkernel is reserved via memblock_reserve(). memblock_free_all() will call free_low_memory_core_early(), which will go over all reserved memblocks, marking the pages as PG_reserved. So manually marking pages as PG_reserved is not necessary, they are already in the desired state (otherwise they would have been handed over to the buddy as free pages and bad things would happen). Link: http://lkml.kernel.org/r/20190114125903.24845-8-david@redhat.comSigned-off-by:
Matthias Brugger <mbrugger@suse.com> Reviewed-by:
Bhupesh Sharma <bhsharma@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Stefan Agner <stefan@agner.ch> Cc: Laura Abbott <labbott@redhat.com> Cc: Greg Hackmann <ghackmann@android.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kristina Martsenko <kristina.martsenko@arm.com> Cc: CHANDAN VN <chandan.vn@samsung.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Logan Gunthorpe <logang@deltatee.com> Signed-off-by:
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David Hildenbrand authored
This will be done by free_reserved_page(). Link: http://lkml.kernel.org/r/20190114125903.24845-7-david@redhat.comSigned-off-by:
James Morse <james.morse@arm.com> Reviewed-by:
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David Hildenbrand authored
The PG_reserved flag is cleared from memory that is part of the kernel image (and therefore marked as PG_reserved). Avoid using PG_reserved directly. Link: http://lkml.kernel.org/r/20190114125903.24845-6-david@redhat.comSigned-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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David Hildenbrand authored
The VDSO is part of the kernel image and therefore the struct pages are marked as reserved during boot. As we install a special mapping, the actual struct pages will never be exposed to MM via the page tables. We can therefore leave the pages marked as reserved. Link: http://lkml.kernel.org/r/20190114125903.24845-5-david@redhat.comSigned-off-by:
Palmer Dabbelt <palmer@sifive.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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David Hildenbrand authored
The VDSO is part of the kernel image and therefore the struct pages are marked as reserved during boot. As we install a special mapping, the actual struct pages will never be exposed to MM via the page tables. We can therefore leave the pages marked as reserved. Link: http://lkml.kernel.org/r/20190114125903.24845-4-david@redhat.comSigned-off-by:
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David Hildenbrand authored
The VDSO is part of the kernel image and therefore the struct pages are marked as reserved during boot. As we install a special mapping, the actual struct pages will never be exposed to MM via the page tables. We can therefore leave the pages marked as reserved. Link: http://lkml.kernel.org/r/20190114125903.24845-3-david@redhat.comSigned-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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David Hildenbrand authored
Patch series "mm: PG_reserved cleanups and documentation", v2. I was recently going over all users of PG_reserved. Short story: it is difficult and sometimes not really clear if setting/checking for PG_reserved is only a relict from the past. Easy to break things. I guess I now have a pretty good idea wh things are like that nowadays and how they evolved. I had way more cleanups in this series inititally, but some architectures take PG_reserved as a way to apply a different caching strategy (for MMIO pages). So I decided to only include the most obvious changes (that are less likely to break something). So the big chunk of manual SetPageReserved users are MMIO/DMA related things on device buffers. Most notably, for device memory we will hopefully soon stop setting PG_reserved. Then the documentation has to be updated. This patch (of 9): The l1 GATT page table is kept in a special on-chip page with 64 entries. We allocate the l2 page table pages via get_zeroed_page() and enter them into the table. These l2 pages are modified accordingly when inserting/removing memory via efficeon_insert_memory and efficeon_remove_memory. Apart from that, these pages are not exposed or ioremap'ed. We can stop setting them reserved (propably copied from generic code). Link: http://lkml.kernel.org/r/20190114125903.24845-2-david@redhat.comSigned-off-by:
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Vineeth Remanan Pillai authored
This patch was initially posted by Kelley Nielsen. Reposting the patch with all review comments addressed and with minor modifications and optimizations. Also, folding in the fixes offered by Hugh Dickins and Huang Ying. Tests were rerun and commit message updated with new results. try_to_unuse() is of quadratic complexity, with a lot of wasted effort. It unuses swap entries one by one, potentially iterating over all the page tables for all the processes in the system for each one. This new proposed implementation of try_to_unuse simplifies its complexity to linear. It iterates over the system's mms once, unusing all the affected entries as it walks each set of page tables. It also makes similar changes to shmem_unuse. Improvement swapoff was called on a swap partition containing about 6G of data, in a VM(8cpu, 16G RAM), and calls to unuse_pte_range() were counted. Present implementation....about 1200M calls(8min, avg 80% cpu util). Prototype.................about 9.0K calls(3min, avg 5% cpu util). Details In shmem_unuse(), iterate over the shmem_swaplist and, for each shmem_inode_info that contains a swap entry, pass it to shmem_unuse_inode(), along with the swap type. In shmem_unuse_inode(), iterate over its associated xarray, and store the index and value of each swap entry in an array for passing to shmem_swapin_page() outside of the RCU critical section. In try_to_unuse(), instead of iterating over the entries in the type and unusing them one by one, perhaps walking all the page tables for all the processes for each one, iterate over the mmlist, making one pass. Pass each mm to unuse_mm() to begin its page table walk, and during the walk, unuse all the ptes that have backing store in the swap type received by try_to_unuse(). After the walk, check the type for orphaned swap entries with find_next_to_unuse(), and remove them from the swap cache. If find_next_to_unuse() starts over at the beginning of the type, repeat the check of the shmem_swaplist and the walk a maximum of three times. Change unuse_mm() and the intervening walk functions down to unuse_pte_range() to take the type as a parameter, and to iterate over their entire range, calling the next function down on every iteration. In unuse_pte_range(), make a swap entry from each pte in the range using the passed in type. If it has backing store in the type, call swapin_readahead() to retrieve the page and pass it to unuse_pte(). Pass the count of pages_to_unuse down the page table walks in try_to_unuse(), and return from the walk when the desired number of pages has been swapped back in. Link: http://lkml.kernel.org/r/20190114153129.4852-2-vpillai@digitalocean.comSigned-off-by:
Vineeth Remanan Pillai <vpillai@digitalocean.com> Signed-off-by:
Kelley Nielsen <kelleynnn@gmail.com> Signed-off-by:
Huang Ying <ying.huang@intel.com> Acked-by:
Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@surriel.com> Signed-off-by:
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Vineeth Remanan Pillai authored
swapin logic can be reused independently without rest of the logic in shmem_getpage_gfp. So lets refactor it out as an independent function. Link: http://lkml.kernel.org/r/20190114153129.4852-1-vpillai@digitalocean.comSigned-off-by:
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Kirill Tkhai authored
We may simply check for sc->may_unmap in isolate_lru_pages() instead of doing that in both of its callers. Link: http://lkml.kernel.org/r/154748280735.29962.15867846875217618569.stgit@localhost.localdomainSigned-off-by:
Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
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Vlastimil Babka authored
Syzbot with KMSAN reports (excerpt): ================================================================== BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:353 [inline] BUG: KMSAN: uninit-value in mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 CPU: 1 PID: 17420 Comm: syz-executor4 Not tainted 4.20.0-rc7+ #15 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613 __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:295 mpol_rebind_policy mm/mempolicy.c:353 [inline] mpol_rebind_mm+0x249/0x370 mm/mempolicy.c:384 update_tasks_nodemask+0x608/0xca0 kernel/cgroup/cpuset.c:1120 update_nodemasks_hier kernel/cgroup/cpuset.c:1185 [inline] update_nodemask kernel/cgroup/cpuset.c:1253 [inline] cpuset_write_resmask+0x2a98/0x34b0 kernel/cgroup/cpuset.c:1728 ... Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline] kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 kmem_cache_alloc+0x572/0xb90 mm/slub.c:2777 mpol_new mm/mempolicy.c:276 [inline] do_mbind mm/mempolicy.c:1180 [inline] kernel_mbind+0x8a7/0x31a0 mm/mempolicy.c:1347 __do_sys_mbind mm/mempolicy.c:1354 [inline] As it's difficult to report where exactly the uninit value resides in the mempolicy object, we have to guess a bit. mm/mempolicy.c:353 contains this part of mpol_rebind_policy(): if (!mpol_store_user_nodemask(pol) && nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) "mpol_store_user_nodemask(pol)" is testing pol->flags, which I couldn't ever see being uninitialized after leaving mpol_new(). So I'll guess it's actually about accessing pol->w.cpuset_mems_allowed on line 354, but still part of statement starting on line 353. For w.cpuset_mems_allowed to be not initialized, and the nodes_equal() reachable for a mempolicy where mpol_set_nodemask() is called in do_mbind(), it seems the only possibility is a MPOL_PREFERRED policy with empty set of nodes, i.e. MPOL_LOCAL equivalent, with MPOL_F_LOCAL flag. Let's exclude such policies from the nodes_equal() check. Note the uninit access should be benign anyway, as rebinding this kind of policy is always a no-op. Therefore no actual need for stable inclusion. Link: http://lkml.kernel.org/r/a71997c3-e8ae-a787-d5ce-3db05768b27c@suse.cz Link: http://lkml.kernel.org/r/73da3e9c-cc84-509e-17d9-0c434bb9967d@suse.czSigned-off-by:Vlastimil Babka <vbabka@suse.cz> Reported-by: syzbot+b19c2dc2c990ea657a71@syzkaller.appspotmail.com Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: zhong jiang <zhongjiang@huawei.com> Signed-off-by:
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Tetsuo Handa authored
If a memory cgroup contains a single process with many threads (including different process group sharing the mm) then it is possible to trigger a race when the oom killer complains that there are no oom elible tasks and complain into the log which is both annoying and confusing because there is no actual problem. The race looks as follows: P1 oom_reaper P2 try_charge try_charge mem_cgroup_out_of_memory mutex_lock(oom_lock) out_of_memory oom_kill_process(P1,P2) wake_oom_reaper mutex_unlock(oom_lock) oom_reap_task mutex_lock(oom_lock) select_bad_process # no victim The problem is more visible with many threads. Fix this by checking for fatal_signal_pending from mem_cgroup_out_of_memory when the oom_lock is already held. The oom bypass is safe because we do the same early in the try_charge path already. The situation migh have changed in the mean time. It should be safe to check for fatal_signal_pending and tsk_is_oom_victim but for a better code readability abstract the current charge bypass condition into should_force_charge and reuse it from that path. " Link: http://lkml.kernel.org/r/01370f70-e1f6-ebe4-b95e-0df21a0bc15e@i-love.sakura.ne.jpSigned-off-by:Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by:
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Mike Rapoport authored
There are two early memory allocations that use memblock_alloc_node_nopanic() and do not check its return value. While this happens very early during boot and chances that the allocation will fail are diminishing, it is still worth to have proper checks for the allocation errors. Link: http://lkml.kernel.org/r/1547734941-944-1-git-send-email-rppt@linux.ibm.comSigned-off-by:
Mike Rapoport <rppt@linux.ibm.com> Reviewed-by:
William Kucharski <william.kucharski@oracle.com> Signed-off-by:
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Aneesh Kumar K.V authored
NestMMU requires us to mark the pte invalid and flush the tlb when we do a RW upgrade of pte. We fixed a variant of this in the fault path in bd5050e3 ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang"). Link: http://lkml.kernel.org/r/20190116085035.29729-6-aneesh.kumar@linux.ibm.comSigned-off-by:
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Aneesh Kumar K.V authored
Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Follow the regular pte change protection sequence for hugetlb too. This allows the architectures to override the update sequence. Link: http://lkml.kernel.org/r/20190116085035.29729-5-aneesh.kumar@linux.ibm.comSigned-off-by:
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Aneesh Kumar K.V authored
NestMMU requires us to mark the pte invalid and flush the tlb when we do a RW upgrade of pte. We fixed a variant of this in the fault path in bd5050e3 ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang"). Do the same for mprotect upgrades. Hugetlb is handled in the next patch. Link: http://lkml.kernel.org/r/20190116085035.29729-4-aneesh.kumar@linux.ibm.comSigned-off-by:
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Aneesh Kumar K.V authored
Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Enable that by passing old pte value as the arg. Link: http://lkml.kernel.org/r/20190116085035.29729-3-aneesh.kumar@linux.ibm.comSigned-off-by:
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Aneesh Kumar K.V authored
Patch series "NestMMU pte upgrade workaround for mprotect", v5. We can upgrade pte access (R -> RW transition) via mprotect. We need to make sure we follow the recommended pte update sequence as outlined in commit bd5050e3 ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") for such updates. This patch series does that. This patch (of 5): Some architectures may want to call flush_tlb_range from these helpers. Link: http://lkml.kernel.org/r/20190116085035.29729-2-aneesh.kumar@linux.ibm.comSigned-off-by:
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Wei Yang authored
No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.comSigned-off-by:
Wei Yang <richard.weiyang@gmail.com> Reviewed-by:
Pekka Enberg <penberg@kernel.org> Acked-by:
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Changbin Du authored
Move the PAGE_OWNER option from submenu "Compile-time checks and compiler options" to dedicated submenu "Memory Debugging". Link: http://lkml.kernel.org/r/20190120024254.6270-1-changbin.du@gmail.comSigned-off-by:
Changbin Du <changbin.du@gmail.com> Acked-by:
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Yang Fan authored
The variable 'addr' is redundant in arch_get_unmapped_area_topdown(), just use parameter 'addr0' directly. Then remove the const qualifier of the parameter, and change its name to 'addr'. And in according with other functions, remove the const qualifier of all other no-pointer parameters in function arch_get_unmapped_area_topdown(). Link: http://lkml.kernel.org/r/20190127041112.25599-1-nullptr.cpp@gmail.comSigned-off-by:
Yang Fan <nullptr.cpp@gmail.com> Reviewed-by:
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Shakeel Butt authored
Since the start of the git history of Linux, the kernel after selecting the worst process to be oom-killed, prefer to kill its child (if the child does not share mm with the parent). Later it was changed to prefer to kill a child who is worst. If the parent is still the worst then the parent will be killed. This heuristic assumes that the children did less work than their parent and by killing one of them, the work lost will be less. However this is very workload dependent. If there is a workload which can benefit from this heuristic, can use oom_score_adj to prefer children to be killed before the parent. The select_bad_process() has already selected the worst process in the system/memcg. There is no need to recheck the badness of its children and hoping to find a worse candidate. That's a lot of unneeded racy work. Also the heuristic is dangerous because it make fork bomb like workloads to recover much later because we constantly pick and kill processes which are not memory hogs. So, let's remove this whole heuristic. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190121215850.221745-2-shakeelb@google.comSigned-off-by:
Shakeel Butt <shakeelb@google.com> Acked-by:
Roman Gushchin <guro@fb.com> Acked-by:
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Greg Kroah-Hartman authored
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.orgSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Laura Abbott <labbott@redhat.com> Signed-off-by:
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Matthew Wilcox authored
Pages which use page_type must never be mapped to userspace as it would destroy their page type. Add an explicit check for this instead of assuming that kernel drivers always get this right. Link: http://lkml.kernel.org/r/20190129053830.3749-1-willy@infradead.orgSigned-off-by:
Matthew Wilcox <willy@infradead.org> Reviewed-by:
Kees Cook <keescook@chromium.org> Reviewed-by:
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Matthew Wilcox authored
It's never appropriate to map a page allocated by SLAB into userspace. A buggy device driver might try this, or an attacker might be able to find a way to make it happen. Christoph said: : Let's just fail the code. Currently this may work with SLUB. But SLAB : and SLOB overlay fields with mapcount. So you would have a corrupted page : struct if you mapped a slab page to user space. Link: http://lkml.kernel.org/r/20190125173827.2658-1-willy@infradead.orgSigned-off-by:
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Uladzislau Rezki (Sony) authored
One of the vmalloc stress test case triggers the kernel BUG(): <snip> [60.562151] ------------[ cut here ]------------ [60.562154] kernel BUG at mm/vmalloc.c:512! [60.562206] invalid opcode: 0000 [#1] PREEMPT SMP PTI [60.562247] CPU: 0 PID: 430 Comm: vmalloc_test/0 Not tainted 4.20.0+ #161 [60.562293] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [60.562351] RIP: 0010:alloc_vmap_area+0x36f/0x390 <snip> it can happen due to big align request resulting in overflowing of calculated address, i.e. it becomes 0 after ALIGN()'s fixup. Fix it by checking if calculated address is within vstart/vend range. Link: http://lkml.kernel.org/r/20190124115648.9433-2-urezki@gmail.comSigned-off-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by:
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Chris Down authored
memcg has a significant number of files exposed to kernfs where their value is either exposed directly or is "max" in the case of PAGE_COUNTER_MAX. This patch makes this generic by providing a single function to do this work. In combination with the previous patch adding mem_cgroup_from_seq, this makes all of the seq_show feeder functions significantly more simple. Link: http://lkml.kernel.org/r/20190124194100.GA31425@chrisdown.nameSigned-off-by:
Chris Down <chris@chrisdown.name> Acked-by:
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Chris Down authored
This is the start of a series of patches similar to my earlier DEFINE_MEMCG_MAX_OR_VAL work, but with less Macro Magic(tm). There are a bunch of places we go from seq_file to mem_cgroup, which currently requires manually getting the css, then getting the mem_cgroup from the css. It's in enough places now that having mem_cgroup_from_seq makes sense (and also makes the next patch a bit nicer). Link: http://lkml.kernel.org/r/20190124194050.GA31341@chrisdown.nameSigned-off-by:
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Johannes Weiner authored
Cgroup has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Link: http://lkml.kernel.org/r/20190124211518.244221-3-surenb@google.comSigned-off-by:
Suren Baghdasaryan <surenb@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
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Johannes Weiner authored
Patch series "psi: pressure stall monitors", v3. Android is adopting psi to detect and remedy memory pressure that results in stuttering and decreased responsiveness on mobile devices. Psi gives us the stall information, but because we're dealing with latencies in the millisecond range, periodically reading the pressure files to detect stalls in a timely fashion is not feasible. Psi also doesn't aggregate its averages at a high enough frequency right now. This patch series extends the psi interface such that users can configure sensitive latency thresholds and use poll() and friends to be notified when these are breached. As high-frequency aggregation is costly, it implements an aggregation method that is optimized for fast, short-interval averaging, and makes the aggregation frequency adaptive, such that high-frequency updates only happen while monitored stall events are actively occurring. With these patches applied, Android can monitor for, and ward off, mounting memory shortages before they cause problems for the user. For example, using memory stall monitors in userspace low memory killer daemon (lmkd) we can detect mounting pressure and kill less important processes before device becomes visibly sluggish. In our memory stress testing psi memory monitors produce roughly 10x less false positives compared to vmpressure signals. Having ability to specify multiple triggers for the same psi metric allows other parts of Android framework to monitor memory state of the device and act accordingly. The new interface is straightforward. The user opens one of the pressure files for writing and writes a trigger description into the file descriptor that defines the stall state - some or full, and the maximum stall time over a given window of time. E.g.: /* Signal when stall time exceeds 100ms of a 1s window */ char trigger[] = "full 100000 1000000"; fd = open("/proc/pressure/memory"); write(fd, trigger, sizeof(trigger)); while (poll() >= 0) { ... } close(fd); When the monitored stall state is entered, psi adapts its aggregation frequency according to what the configured time window requires in order to emit event signals in a timely fashion. Once the stalling subsides, aggregation reverts back to normal. The trigger is associated with the open file descriptor. To stop monitoring, the user only needs to close the file descriptor and the trigger is discarded. Patches 1-4 prepare the psi code for polling support. Patch 5 implements the adaptive polling logic, the pressure growth detection optimized for short intervals, and hooks up write() and poll() on the pressure files. The patches were developed in collaboration with Johannes Weiner. This patch (of 5): Kernfs has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Link: http://lkml.kernel.org/r/20190124211518.244221-2-surenb@google.comSigned-off-by: -
Mel Gorman authored
Compaction is inherently race-prone as a suitable page freed during compaction can be allocated by any parallel task. This patch uses a capture_control structure to isolate a page immediately when it is freed by a direct compactor in the slow path of the page allocator. The intent is to avoid redundant scanning. 5.0.0-rc1 5.0.0-rc1 selective-v3r17 capture-v3r19 Amean fault-both-1 0.00 ( 0.00%) 0.00 * 0.00%* Amean fault-both-3 2582.11 ( 0.00%) 2563.68 ( 0.71%) Amean fault-both-5 4500.26 ( 0.00%) 4233.52 ( 5.93%) Amean fault-both-7 5819.53 ( 0.00%) 6333.65 ( -8.83%) Amean fault-both-12 9321.18 ( 0.00%) 9759.38 ( -4.70%) Amean fault-both-18 9782.76 ( 0.00%) 10338.76 ( -5.68%) Amean fault-both-24 15272.81 ( 0.00%) 13379.55 * 12.40%* Amean fault-both-30 15121.34 ( 0.00%) 16158.25 ( -6.86%) Amean fault-both-32 18466.67 ( 0.00%) 18971.21 ( -2.73%) Latency is only moderately affected but the devil is in the details. A closer examination indicates that base page fault latency is reduced but latency of huge pages is increased as it takes creater care to succeed. Part of the "problem" is that allocation success rates are close to 100% even when under pressure and compaction gets harder 5.0.0-rc1 5.0.0-rc1 selective-v3r17 capture-v3r19 Percentage huge-3 96.70 ( 0.00%) 98.23 ( 1.58%) Percentage huge-5 96.99 ( 0.00%) 95.30 ( -1.75%) Percentage huge-7 94.19 ( 0.00%) 97.24 ( 3.24%) Percentage huge-12 94.95 ( 0.00%) 97.35 ( 2.53%) Percentage huge-18 96.74 ( 0.00%) 97.30 ( 0.58%) Percentage huge-24 97.07 ( 0.00%) 97.55 ( 0.50%) Percentage huge-30 95.69 ( 0.00%) 98.50 ( 2.95%) Percentage huge-32 96.70 ( 0.00%) 99.27 ( 2.65%) And scan rates are reduced as expected by 6% for the migration scanner and 29% for the free scanner indicating that there is less redundant work. Compaction migrate scanned 20815362 19573286 Compaction free scanned 16352612 11510663 [mgorman@techsingularity.net: remove redundant check] Link: http://lkml.kernel.org/r/20190201143853.GH9565@techsingularity.net Link: http://lkml.kernel.org/r/20190118175136.31341-23-mgorman@techsingularity.netSigned-off-by:Mel Gorman <mgorman@techsingularity.net> Acked-by:
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Mel Gorman authored
Pageblock hints are cleared when compaction restarts or kswapd makes enough progress that it can sleep but it's over-eager in that the bit is cleared for migration sources with no LRU pages and migration targets with no free pages. As pageblock skip hint flushes are relatively rare and out-of-band with respect to kswapd, this patch makes a few more expensive checks to see if it's appropriate to even clear the bit. Every pageblock that is not cleared will avoid 512 pages being scanned unnecessarily on x86-64. The impact is variable with different workloads showing small differences in latency, success rates and scan rates. This is expected as clearing the hints is not that common but doing a small amount of work out-of-band to avoid a large amount of work in-band later is generally a good thing. Link: http://lkml.kernel.org/r/20190118175136.31341-22-mgorman@techsingularity.netSigned-off-by:
Qian Cai <cai@lca.pw> Acked-by:
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