- 15 12月, 2016 18 次提交
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由 Jan Kara 提交于
DAX will need to implement its own version of page_check_address(). To avoid duplicating page table walking code, export follow_pte() which does what we need. Link: http://lkml.kernel.org/r/1479460644-25076-18-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Currently finish_mkwrite_fault() returns 0 when PTE got changed before we acquired PTE lock and VM_FAULT_WRITE when we succeeded in modifying the PTE. This is somewhat confusing since 0 generally means success, it is also inconsistent with finish_fault() which returns 0 on success. Change finish_mkwrite_fault() to return 0 on success and VM_FAULT_NOPAGE when PTE changed. Practically, there should be no behavioral difference since we bail out from the fault the same way regardless whether we return 0, VM_FAULT_NOPAGE, or VM_FAULT_WRITE. Also note that VM_FAULT_WRITE has no effect for shared mappings since the only two places that check it - KSM and GUP - care about private mappings only. Generally the meaning of VM_FAULT_WRITE for shared mappings is not well defined and we should probably clean that up. Link: http://lkml.kernel.org/r/1479460644-25076-17-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Provide a helper function for finishing write faults due to PTE being read-only. The helper will be used by DAX to avoid the need of complicating generic MM code with DAX locking specifics. Link: http://lkml.kernel.org/r/1479460644-25076-16-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
wp_page_reuse() handles write shared faults which is needed only in wp_page_shared(). Move the handling only into that location to make wp_page_reuse() simpler and avoid a strange situation when we sometimes pass in locked page, sometimes unlocked etc. Link: http://lkml.kernel.org/r/1479460644-25076-15-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
So far we set vmf->page during WP faults only when we needed to pass it to the ->page_mkwrite handler. Set it in all the cases now and use that instead of passing page pointer explicitly around. Link: http://lkml.kernel.org/r/1479460644-25076-14-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
We will need more information in the ->page_mkwrite() helper for DAX to be able to fully finish faults there. Pass vm_fault structure to do_page_mkwrite() and use it there so that information propagates properly from upper layers. Link: http://lkml.kernel.org/r/1479460644-25076-13-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Currently we duplicate handling of shared write faults in wp_page_reuse() and do_shared_fault(). Factor them out into a common function. Link: http://lkml.kernel.org/r/1479460644-25076-12-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Move final handling of COW faults from generic code into DAX fault handler. That way generic code doesn't have to be aware of peculiarities of DAX locking so remove that knowledge and make locking functions private to fs/dax.c. Link: http://lkml.kernel.org/r/1479460644-25076-11-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Introduce finish_fault() as a helper function for finishing page faults. It is rather thin wrapper around alloc_set_pte() but since we'd want to call this from DAX code or filesystems, it is still useful to avoid some boilerplate code. Link: http://lkml.kernel.org/r/1479460644-25076-10-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Patch series "dax: Clear dirty bits after flushing caches", v5. Patchset to clear dirty bits from radix tree of DAX inodes when caches for corresponding pfns have been flushed. In principle, these patches enable handlers to easily update PTEs and do other work necessary to finish the fault without duplicating the functionality present in the generic code. I'd like to thank Kirill and Ross for reviews of the series! This patch (of 20): To allow full handling of COW faults add memcg field to struct vm_fault and a return value of ->fault() handler meaning that COW fault is fully handled and memcg charge must not be canceled. This will allow us to remove knowledge about special DAX locking from the generic fault code. Link: http://lkml.kernel.org/r/1479460644-25076-9-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Add orig_pte field to vm_fault structure to allow ->page_mkwrite handlers to fully handle the fault. This also allows us to save some passing of extra arguments around. Link: http://lkml.kernel.org/r/1479460644-25076-8-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Instead of creating another vm_fault structure, use the one passed to wp_pfn_shared() for passing arguments into pfn_mkwrite handler. Link: http://lkml.kernel.org/r/1479460644-25076-7-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Use vm_fault structure to pass cow_page, page, and entry in and out of the function. That reduces number of __do_fault() arguments from 4 to 1. Link: http://lkml.kernel.org/r/1479460644-25076-6-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Instead of creating another vm_fault structure, use the one passed to __do_fault() for passing arguments into fault handler. Link: http://lkml.kernel.org/r/1479460644-25076-5-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
struct vm_fault has already pgoff entry. Use it instead of passing pgoff as a separate argument and then assigning it later. Link: http://lkml.kernel.org/r/1479460644-25076-4-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Every single user of vmf->virtual_address typed that entry to unsigned long before doing anything with it so the type of virtual_address does not really provide us any additional safety. Just use masked vmf->address which already has the appropriate type. Link: http://lkml.kernel.org/r/1479460644-25076-3-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Currently we have two different structures for passing fault information around - struct vm_fault and struct fault_env. DAX will need more information in struct vm_fault to handle its faults so the content of that structure would become event closer to fault_env. Furthermore it would need to generate struct fault_env to be able to call some of the generic functions. So at this point I don't think there's much use in keeping these two structures separate. Just embed into struct vm_fault all that is needed to use it for both purposes. Link: http://lkml.kernel.org/r/1479460644-25076-2-git-send-email-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lorenzo Stoakes 提交于
Patch series "mm: unexport __get_user_pages_unlocked()". This patch series continues the cleanup of get_user_pages*() functions taking advantage of the fact we can now pass gup_flags as we please. It firstly adds an additional 'locked' parameter to get_user_pages_remote() to allow for its callers to utilise VM_FAULT_RETRY functionality. This is necessary as the invocation of __get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of this and no other existing higher level function would allow it to do so. Secondly existing callers of __get_user_pages_unlocked() are replaced with the appropriate higher-level replacement - get_user_pages_unlocked() if the current task and memory descriptor are referenced, or get_user_pages_remote() if other task/memory descriptors are referenced (having acquiring mmap_sem.) This patch (of 2): Add a int *locked parameter to get_user_pages_remote() to allow VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked(). Taking into account the previous adjustments to get_user_pages*() functions allowing for the passing of gup_flags, we are now in a position where __get_user_pages_unlocked() need only be exported for his ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to subsequently unexport __get_user_pages_unlocked() as well as allowing for future flexibility in the use of get_user_pages_remote(). [sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change] Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.comSigned-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 12月, 2016 4 次提交
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由 Aneesh Kumar K.V 提交于
Add arch specific callback in the generic THP page cache code that will deposit and withdarw preallocated page table. Archs like ppc64 use this preallocated table to store the hash pte slot information. Testing: kernel build of the patch series on tmpfs mounted with option huge=always The related thp stat: thp_fault_alloc 72939 thp_fault_fallback 60547 thp_collapse_alloc 603 thp_collapse_alloc_failed 0 thp_file_alloc 253763 thp_file_mapped 4251 thp_split_page 51518 thp_split_page_failed 1 thp_deferred_split_page 73566 thp_split_pmd 665 thp_zero_page_alloc 3 thp_zero_page_alloc_failed 0 [akpm@linux-foundation.org: remove unneeded parentheses, per Kirill] Link: http://lkml.kernel.org/r/20161113150025.17942-2-aneesh.kumar@linux.vnet.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Aneesh Kumar K.V 提交于
Now that we check for page size change early in the loop, we can partially revert e9d55e15 ("mm: change the interface for __tlb_remove_page"). This simplies the code much, by removing the need to track the last address with which we adjusted the range. We also go back to the older way of filling the mmu_gather array, ie, we add an entry and then check whether the gather batch is full. Link: http://lkml.kernel.org/r/20161026084839.27299-6-aneesh.kumar@linux.vnet.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Aneesh Kumar K.V 提交于
With commit e77b0852 ("mm/mmu_gather: track page size with mmu gather and force flush if page size change") we added the ability to force a tlb flush when the page size change in a mmu_gather loop. We did that by checking for a page size change every time we added a page to mmu_gather for lazy flush/remove. We can improve that by moving the page size change check early and not doing it every time we add a page. This also helps us to do tlb flush when invalidating a range covering dax mapping. Wrt dax mapping we don't have a backing struct page and hence we don't call tlb_remove_page, which earlier forced the tlb flush on page size change. Moving the page size change check earlier means we will do the same even for dax mapping. We also avoid doing this check on architecture other than powerpc. In a later patch we will remove page size check from tlb_remove_page(). Link: http://lkml.kernel.org/r/20161026084839.27299-5-aneesh.kumar@linux.vnet.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 David Rientjes 提交于
While doing MADV_DONTNEED on a large area of thp memory, I noticed we encountered many unlikely() branches in profiles for each backing hugepage. This is because zap_pmd_range() would call split_huge_pmd(), which rechecked the conditions that were already validated, but as part of an unlikely() branch. Avoid the unlikely() branch when in a context where pmd is known to be good for __split_huge_pmd() directly. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1610181600300.84525@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 11月, 2016 2 次提交
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由 Catalin Marinas 提交于
The flush_icache_range() API is meant to be used on kernel addresses only as it may not have the infrastructure (exception entries) to handle user memory faults. The lkdtm execute_user_location() function tests the kernel execution of user space addresses by mmap'ing an anonymous page, copying some code together with cache maintenance and attempting to run it. However, the cache maintenance step may fail because of the incorrect API usage described above. The patch changes lkdtm to use access_process_vm() for copying the code into user space which would take care of the necessary cache maintenance. Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com> [kees: export access_process_vm() for module use] Signed-off-by: NKees Cook <keescook@chromium.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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由 Borislav Petkov 提交于
It only returns 0 so we can save us the testing of its retval everywhere. Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: mcgrof@suse.com Cc: dri-devel@lists.freedesktop.org Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Airlie <airlied@redhat.com> Cc: dan.j.williams@intel.com Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/20161026174839.rusfxkm3xt4ennhe@pd.tnicSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 19 10月, 2016 4 次提交
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由 Lorenzo Stoakes 提交于
This removes the 'write' argument from access_process_vm() and replaces it with 'gup_flags' as use of this function previously silently implied FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NJesper Nilsson <jesper.nilsson@axis.com> Acked-by: NMichal Hocko <mhocko@suse.com> Acked-by: NMichael Ellerman <mpe@ellerman.id.au> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lorenzo Stoakes 提交于
This removes the 'write' argument from access_remote_vm() and replaces it with 'gup_flags' as use of this function previously silently implied FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lorenzo Stoakes 提交于
This removes the 'write' argument from __access_remote_vm() and replaces it with 'gup_flags' as use of this function previously silently implied FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lorenzo Stoakes 提交于
This removes the 'write' and 'force' from get_user_pages_remote() and replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NMichal Hocko <mhocko@suse.com> Reviewed-by: NJan Kara <jack@suse.cz> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 10月, 2016 2 次提交
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由 Dan Williams 提交于
vm_insert_mixed() unlike vm_insert_pfn_prot() and vmf_insert_pfn_pmd(), fails to check the pgprot_t it uses for the mapping against the one recorded in the memtype tracking tree. Add the missing call to track_pfn_insert() to preclude cases where incompatible aliased mappings are established for a given physical address range. Link: http://lkml.kernel.org/r/147328717909.35069.14256589123570653697.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: NDan Williams <dan.j.williams@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Michal Hocko 提交于
There are only few use_mm() users in the kernel right now. Most of them write to the target memory but vhost driver relies on copy_from_user/get_user from a kernel thread context. This makes it impossible to reap the memory of an oom victim which shares the mm with the vhost kernel thread because it could see a zero page unexpectedly and theoretically make an incorrect decision visible outside of the killed task context. To quote Michael S. Tsirkin: : Getting an error from __get_user and friends is handled gracefully. : Getting zero instead of a real value will cause userspace : memory corruption. The vhost kernel thread is bound to an open fd of the vhost device which is not tight to the mm owner life cycle in general. The device fd can be inherited or passed over to another process which means that we really have to be careful about unexpected memory corruption because unlike for normal oom victims the result will be visible outside of the oom victim context. Make sure that no kthread context (users of use_mm) can ever see corrupted data because of the oom reaper and hook into the page fault path by checking MMF_UNSTABLE mm flag. __oom_reap_task_mm will set the flag before it starts unmapping the address space while the flag is checked after the page fault has been handled. If the flag is set then SIGBUS is triggered so any g-u-p user will get a error code. Regular tasks do not need this protection because all which share the mm are killed when the mm is reaped and so the corruption will not outlive them. This patch shouldn't have any visible effect at this moment because the OOM killer doesn't invoke oom reaper for tasks with mm shared with kthreads yet. Link: http://lkml.kernel.org/r/1472119394-11342-9-git-send-email-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com> Acked-by: N"Michael S. Tsirkin" <mst@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 9月, 2016 1 次提交
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由 Lorenzo Stoakes 提交于
The NUMA balancing logic uses an arch-specific PROT_NONE page table flag defined by pte_protnone() or pmd_protnone() to mark PTEs or huge page PMDs respectively as requiring balancing upon a subsequent page fault. User-defined PROT_NONE memory regions which also have this flag set will not normally invoke the NUMA balancing code as do_page_fault() will send a segfault to the process before handle_mm_fault() is even called. However if access_remote_vm() is invoked to access a PROT_NONE region of memory, handle_mm_fault() is called via faultin_page() and __get_user_pages() without any access checks being performed, meaning the NUMA balancing logic is incorrectly invoked on a non-NUMA memory region. A simple means of triggering this problem is to access PROT_NONE mmap'd memory using /proc/self/mem which reliably results in the NUMA handling functions being invoked when CONFIG_NUMA_BALANCING is set. This issue was reported in bugzilla (issue 99101) which includes some simple repro code. There are BUG_ON() checks in do_numa_page() and do_huge_pmd_numa_page() added at commit c0e7cad9 to avoid accidentally provoking strange behaviour by attempting to apply NUMA balancing to pages that are in fact PROT_NONE. The BUG_ON()'s are consistently triggered by the repro. This patch moves the PROT_NONE check into mm/memory.c rather than invoking BUG_ON() as faulting in these pages via faultin_page() is a valid reason for reaching the NUMA check with the PROT_NONE page table flag set and is therefore not always a bug. Link: https://bugzilla.kernel.org/show_bug.cgi?id=99101Reported-by: NTrevor Saunders <tbsaunde@tbsaunde.org> Signed-off-by: NLorenzo Stoakes <lstoakes@gmail.com> Acked-by: NRik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 9月, 2016 1 次提交
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由 Rik van Riel 提交于
Commit: 4d942466 ("mm: convert p[te|md]_mknonnuma and remaining page table manipulations") changed NUMA balancing from _PAGE_NUMA to using PROT_NONE, and was quickly found to introduce a regression with NUMA grouping. It was followed up by these commits: 53da3bc2 ("mm: fix up numa read-only thread grouping logic") bea66fbd ("mm: numa: group related processes based on VMA flags instead of page table flags") b191f9b1 ("mm: numa: preserve PTE write permissions across a NUMA hinting fault") The first of those two commits try alternate approaches to NUMA grouping, which apparently do not work as well as looking at the PTE write permissions. The latter patch preserves the PTE write permissions across a NUMA protection fault. However, it forgets to revert the condition for whether or not to group tasks together back to what it was before v3.19, even though the information is now preserved in the page tables once again. This patch brings the NUMA grouping heuristic back to what it was before commit 4d942466, which the changelogs of subsequent commits suggest worked best. We have all the information again. We should probably use it. Signed-off-by: NRik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: aarcange@redhat.com Cc: linux-mm@kvack.org Cc: mgorman@suse.de Link: http://lkml.kernel.org/r/20160908213053.07c992a9@annuminas.surriel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 03 8月, 2016 2 次提交
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由 Minchan Kim 提交于
Every swap-in anonymous page starts from inactive lru list's head. It should be activated unconditionally when VM decide to reclaim because page table entry for the page always usually has marked accessed bit. Thus, their window size for getting a new referece is 2 * NR_inactive + NR_active while others is NR_inactive + NR_active. It's not fair that it has more chance to be referenced compared to other newly allocated page which starts from active lru list's head. Johannes: : The page can still have a valid copy on the swap device, so prefering to : reclaim that page over a fresh one could make sense. But as you point : out, having it start inactive instead of active actually ends up giving it : *more* LRU time, and that seems to be without justification. Rik: : The reason newly read in swap cache pages start on the inactive list is : that we do some amount of read-around, and do not know which pages will : get used. : : However, immediately activating the ones that DO get used, like your patch : does, is the right thing to do. Link: http://lkml.kernel.org/r/1469762740-17860-1-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NRik van Riel <riel@redhat.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Vegard Nossum 提交于
I ran into this: BUG: sleeping function called from invalid context at mm/page_alloc.c:3784 in_atomic(): 0, irqs_disabled(): 0, pid: 1434, name: trinity-c1 2 locks held by trinity-c1/1434: #0: (&mm->mmap_sem){......}, at: [<ffffffff810ce31e>] __do_page_fault+0x1ce/0x8f0 #1: (rcu_read_lock){......}, at: [<ffffffff81378f86>] filemap_map_pages+0xd6/0xdd0 CPU: 0 PID: 1434 Comm: trinity-c1 Not tainted 4.7.0+ #58 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x65/0x84 panic+0x185/0x2dd ___might_sleep+0x51c/0x600 __might_sleep+0x90/0x1a0 __alloc_pages_nodemask+0x5b1/0x2160 alloc_pages_current+0xcc/0x370 pte_alloc_one+0x12/0x90 __pte_alloc+0x1d/0x200 alloc_set_pte+0xe3e/0x14a0 filemap_map_pages+0x42b/0xdd0 handle_mm_fault+0x17d5/0x28b0 __do_page_fault+0x310/0x8f0 trace_do_page_fault+0x18d/0x310 do_async_page_fault+0x27/0xa0 async_page_fault+0x28/0x30 The important bits from the above is that filemap_map_pages() is calling into the page allocator while holding rcu_read_lock (sleeping is not allowed inside RCU read-side critical sections). According to Kirill Shutemov, the prefaulting code in do_fault_around() is supposed to take care of this, but missing error handling means that the allocation failure can go unnoticed. We don't need to return VM_FAULT_OOM (or any other error) here, since we can just let the normal fault path try again. Fixes: 7267ec00 ("mm: postpone page table allocation until we have page to map") Link: http://lkml.kernel.org/r/1469708107-11868-1-git-send-email-vegard.nossum@oracle.comSigned-off-by: NVegard Nossum <vegard.nossum@oracle.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Hillf Danton" <hillf.zj@alibaba-inc.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 7月, 2016 6 次提交
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由 Kirill A. Shutemov 提交于
For file mappings, we don't deposit page tables on THP allocation because it's not strictly required to implement split_huge_pmd(): we can just clear pmd and let following page faults to reconstruct the page table. But Power makes use of deposited page table to address MMU quirk. Let's hide THP page cache, including huge tmpfs, under separate config option, so it can be forbidden on Power. We can revert the patch later once solution for Power found. Link: http://lkml.kernel.org/r/1466021202-61880-36-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
Here's basic implementation of huge pages support for shmem/tmpfs. It's all pretty streight-forward: - shmem_getpage() allcoates huge page if it can and try to inserd into radix tree with shmem_add_to_page_cache(); - shmem_add_to_page_cache() puts the page onto radix-tree if there's space for it; - shmem_undo_range() removes huge pages, if it fully within range. Partial truncate of huge pages zero out this part of THP. This have visible effect on fallocate(FALLOC_FL_PUNCH_HOLE) behaviour. As we don't really create hole in this case, lseek(SEEK_HOLE) may have inconsistent results depending what pages happened to be allocated. - no need to change shmem_fault: core-mm will map an compound page as huge if VMA is suitable; Link: http://lkml.kernel.org/r/1466021202-61880-30-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
File COW for THP is handled on pte level: just split the pmd. It's not clear how benefitial would be allocation of huge pages on COW faults. And it would require some code to make them work. I think at some point we can consider teaching khugepaged to collapse pages in COW mappings, but allocating huge on fault is probably overkill. Link: http://lkml.kernel.org/r/1466021202-61880-16-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
THP_FILE_ALLOC: how many times huge page was allocated and put page cache. THP_FILE_MAPPED: how many times file huge page was mapped. Link: http://lkml.kernel.org/r/1466021202-61880-13-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
With postponed page table allocation we have chance to setup huge pages. do_set_pte() calls do_set_pmd() if following criteria met: - page is compound; - pmd entry in pmd_none(); - vma has suitable size and alignment; Link: http://lkml.kernel.org/r/1466021202-61880-12-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
Naive approach: on mapping/unmapping the page as compound we update ->_mapcount on each 4k page. That's not efficient, but it's not obvious how we can optimize this. We can look into optimization later. PG_double_map optimization doesn't work for file pages since lifecycle of file pages is different comparing to anon pages: file page can be mapped again at any time. Link: http://lkml.kernel.org/r/1466021202-61880-11-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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