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170 Commits
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79f5f8fab4 |
mm,hwpoison: rework soft offline for in-use pages
This patch changes the way we set and handle in-use poisoned pages. Until
now, poisoned pages were released to the buddy allocator, trusting that
the checks that take place at allocation time would act as a safe net and
would skip that page.
This has proved to be wrong, as we got some pfn walkers out there, like
compaction, that all they care is the page to be in a buddy freelist.
Although this might not be the only user, having poisoned pages in the
buddy allocator seems a bad idea as we should only have free pages that
are ready and meant to be used as such.
Before explaining the taken approach, let us break down the kind of pages
we can soft offline.
- Anonymous THP (after the split, they end up being 4K pages)
- Hugetlb
- Order-0 pages (that can be either migrated or invalited)
* Normal pages (order-0 and anon-THP)
- If they are clean and unmapped page cache pages, we invalidate
then by means of invalidate_inode_page().
- If they are mapped/dirty, we do the isolate-and-migrate dance.
Either way, do not call put_page directly from those paths. Instead, we
keep the page and send it to page_handle_poison to perform the right
handling.
page_handle_poison sets the HWPoison flag and does the last put_page.
Down the chain, we placed a check for HWPoison page in
free_pages_prepare, that just skips any poisoned page, so those pages
do not end up in any pcplist/freelist.
After that, we set the refcount on the page to 1 and we increment
the poisoned pages counter.
If we see that the check in free_pages_prepare creates trouble, we can
always do what we do for free pages:
- wait until the page hits buddy's freelists
- take it off, and flag it
The downside of the above approach is that we could race with an
allocation, so by the time we want to take the page off the buddy, the
page has been already allocated so we cannot soft offline it.
But the user could always retry it.
* Hugetlb pages
- We isolate-and-migrate them
After the migration has been successful, we call dissolve_free_huge_page,
and we set HWPoison on the page if we succeed.
Hugetlb has a slightly different handling though.
While for non-hugetlb pages we cared about closing the race with an
allocation, doing so for hugetlb pages requires quite some additional
and intrusive code (we would need to hook in free_huge_page and some other
places).
So I decided to not make the code overly complicated and just fail
normally if the page we allocated in the meantime.
We can always build on top of this.
As a bonus, because of the way we handle now in-use pages, we no longer
need the put-as-isolation-migratetype dance, that was guarding for poisoned
pages to end up in pcplists.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-10-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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06be6ff3d2 |
mm,hwpoison: rework soft offline for free pages
When trying to soft-offline a free page, we need to first take it off the buddy allocator. Once we know is out of reach, we can safely flag it as poisoned. take_page_off_buddy will be used to take a page meant to be poisoned off the buddy allocator. take_page_off_buddy calls break_down_buddy_pages, which splits a higher-order page in case our page belongs to one. Once the page is under our control, we call page_handle_poison to set it as poisoned and grab a refcount on it. Signed-off-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Aristeu Rozanski <aris@ruivo.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dmitry Yakunin <zeil@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20200922135650.1634-9-osalvador@suse.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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a08d93e575 |
mm: simplify PageDoubleMap with PF_SECOND policy
Introduce the new page policy of PF_SECOND which lets us use the normal pageflags generation machinery to create the various DoubleMap manipulation functions. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Link: https://lkml.kernel.org/r/20200629151933.15671-3-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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e18c45ffcf |
mm: move PageDoubleMap bit
Patch series "Fix PageDoubleMap". This is a purely theoretical problem for now as none of the filesystems which use PG_private_2 (ie PG_fscache) are being converted at this time, but it's confusing to leave it like this. This patch (of 2): PG_private_2 is defined as being PF_ANY (applicable to tail pages as well as regular & head pages). That means that the first tail page of a double-map page will appear to have Private2 set. Use the Workingset bit instead which is defined as PF_HEAD so any attempt to access the Workingset bit on a tail page will redirect to the head page's Workingset bit. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Link: https://lkml.kernel.org/r/20200629151933.15671-1-willy@infradead.org Link: https://lkml.kernel.org/r/20200629151933.15671-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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4beba9486a |
mm: Add PG_arch_2 page flag
For arm64 MTE support it is necessary to be able to mark pages that contain user space visible tags that will need to be saved/restored e.g. when swapped out. To support this add a new arch specific flag (PG_arch_2). This flag is only available on 64-bit architectures due to the limited number of spare page flags on the 32-bit ones. Signed-off-by: Steven Price <steven.price@arm.com> [catalin.marinas@arm.com: use CONFIG_64BIT for guarding this new flag] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> |
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aa218795cb |
mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE
virtio-mem wants to allow to offline memory blocks of which some parts were unplugged (allocated via alloc_contig_range()), especially, to later offline and remove completely unplugged memory blocks. The important part is that PageOffline() has to remain set until the section is offline, so these pages will never get accessed (e.g., when dumping). The pages should not be handed back to the buddy (which would require clearing PageOffline() and result in issues if offlining fails and the pages are suddenly in the buddy). Let's allow to do that by allowing to isolate any PageOffline() page when offlining. This way, we can reach the memory hotplug notifier MEM_GOING_OFFLINE, where the driver can signal that he is fine with offlining this page by dropping its reference count. PageOffline() pages with a reference count of 0 can then be skipped when offlining the pages (like if they were free, however they are not in the buddy). Anybody who uses PageOffline() pages and does not agree to offline them (e.g., Hyper-V balloon, XEN balloon, VMWare balloon for 2MB pages) will not decrement the reference count and make offlining fail when trying to migrate such an unmovable page. So there should be no observable change. Same applies to balloon compaction users (movable PageOffline() pages), the pages will simply be migrated. Note 1: If offlining fails, a driver has to increment the reference count again in MEM_CANCEL_OFFLINE. Note 2: A driver that makes use of this has to be aware that re-onlining the memory block has to be handled by hooking into onlining code (online_page_callback_t), resetting the page PageOffline() and not giving them to the buddy. Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Juergen Gross <jgross@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Anthony Yznaga <anthony.yznaga@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Qian Cai <cai@lca.pw> Cc: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20200507140139.17083-7-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
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36e66c554b |
mm: introduce Reported pages
In order to pave the way for free page reporting in virtualized environments we will need a way to get pages out of the free lists and identify those pages after they have been returned. To accomplish this, this patch adds the concept of a Reported Buddy, which is essentially meant to just be the Uptodate flag used in conjunction with the Buddy page type. To prevent the reported pages from leaking outside of the buddy lists I added a check to clear the PageReported bit in the del_page_from_free_list function. As a result any reported page that is split, merged, or allocated will have the flag cleared prior to the PageBuddy value being cleared. The process for reporting pages is fairly simple. Once we free a page that meets the minimum order for page reporting we will schedule a worker thread to start 2s or more in the future. That worker thread will begin working from the lowest supported page reporting order up to MAX_ORDER - 1 pulling unreported pages from the free list and storing them in the scatterlist. When processing each individual free list it is necessary for the worker thread to release the zone lock when it needs to stop and report the full scatterlist of pages. To reduce the work of the next iteration the worker thread will rotate the free list so that the first unreported page in the free list becomes the first entry in the list. It will then call a reporting function providing information on how many entries are in the scatterlist. Once the function completes it will return the pages to the free area from which they were allocated and start over pulling more pages from the free areas until there are no longer enough pages to report on to keep the worker busy, or we have processed as many pages as were contained in the free area when we started processing the list. The worker thread will work in a round-robin fashion making its way though each zone requesting reporting, and through each reportable free list within that zone. Once all free areas within the zone have been processed it will check to see if there have been any requests for reporting while it was processing. If so it will reschedule the worker thread to start up again in roughly 2s and exit. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitesh Narayan Lal <nitesh@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pagupta@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Wang <wei.w.wang@intel.com> Cc: Yang Zhang <yang.zhang.wz@gmail.com> Cc: wei qi <weiqi4@huawei.com> Link: http://lkml.kernel.org/r/20200211224635.29318.19750.stgit@localhost.localdomain Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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9de4f22a60 |
mm: code cleanup for MADV_FREE
Some comments for MADV_FREE is revised and added to help people understand the MADV_FREE code, especially the page flag, PG_swapbacked. This makes page_is_file_cache() isn't consistent with its comments. So the function is renamed to page_is_file_lru() to make them consistent again. All these are put in one patch as one logical change. Suggested-by: David Hildenbrand <david@redhat.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: David Rientjes <rientjes@google.com> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@kernel.org> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@surriel.com> Link: http://lkml.kernel.org/r/20200317100342.2730705-1-ying.huang@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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d72520ad00 |
page-flags: fix a crash at SetPageError(THP_SWAP)
Commit |
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169226f7e0 |
mm: thp: handle page cache THP correctly in PageTransCompoundMap
We have a usecase to use tmpfs as QEMU memory backend and we would like to take the advantage of THP as well. But, our test shows the EPT is not PMD mapped even though the underlying THP are PMD mapped on host. The number showed by /sys/kernel/debug/kvm/largepage is much less than the number of PMD mapped shmem pages as the below: 7f2778200000-7f2878200000 rw-s 00000000 00:14 262232 /dev/shm/qemu_back_mem.mem.Hz2hSf (deleted) Size: 4194304 kB [snip] AnonHugePages: 0 kB ShmemPmdMapped: 579584 kB [snip] Locked: 0 kB cat /sys/kernel/debug/kvm/largepages 12 And some benchmarks do worse than with anonymous THPs. By digging into the code we figured out that commit |
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b877ac9815 |
xen/swiotlb: remember having called xen_create_contiguous_region()
Instead of always calling xen_destroy_contiguous_region() in case the memory is DMA-able for the used device, do so only in case it has been made DMA-able via xen_create_contiguous_region() before. This will avoid a lot of xen_destroy_contiguous_region() calls for 64-bit capable devices. As the memory in question is owned by swiotlb-xen the PG_owner_priv_1 flag of the first allocated page can be used for remembering. Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> |
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3972f6bb1c |
mm, debug_pagealloc: use a page type instead of page_ext flag
When debug_pagealloc is enabled, we currently allocate the page_ext array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that we have the page_type field in struct page, we can use that instead, as guard pages are neither PageSlab nor mapped to userspace. This reduces memory overhead when debug_pagealloc is enabled and there are no other features requiring the page_ext array. Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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6e2e07cd35 |
mm: better document PG_reserved
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.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Anthony Yznaga <anthony.yznaga@oracle.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: <yi.z.zhang@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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ca215086b1 |
mm: convert PG_balloon to PG_offline
PG_balloon was introduced to implement page migration/compaction for pages inflated in virtio-balloon. Nowadays, it is only a marker that a page is part of virtio-balloon and therefore logically offline. We also want to make use of this flag in other balloon drivers - for inflated pages or when onlining a section but keeping some pages offline (e.g. used right now by XEN and Hyper-V via set_online_page_callback()). We are going to expose this flag to dump tools like makedumpfile. But instead of exposing PG_balloon, let's generalize the concept of marking pages as logically offline, so it can be reused for other purposes later on. Rename PG_balloon to PG_offline. This is an indicator that the page is logically offline, the content stale and that it should not be touched (e.g. a hypervisor would have to allocate backing storage in order for the guest to dump an unused page). We can then e.g. exclude such pages from dumps. We replace and reuse KPF_BALLOON (23), as this shouldn't really harm (and for now the semantics stay the same). In following patches, we will make use of this bit also in other balloon drivers. While at it, document PGTABLE. [akpm@linux-foundation.org: fix comment text, per David] Link: http://lkml.kernel.org/r/20181119101616.8901-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Pankaj gupta <pagupta@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Christian Hansen <chansen3@cisco.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: David Rientjes <rientjes@google.com> Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Juergen Gross <jgross@suse.com> Cc: Julien Freche <jfreche@vmware.com> Cc: Kairui Song <kasong@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Len Brown <len.brown@intel.com> Cc: Lianbo Jiang <lijiang@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xavier Deguillard <xdeguillard@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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144552ff89 |
/proc/kpagecount: return 0 for special pages that are never mapped
Certain pages that are never mapped to userspace have a type indicated in the page_type field of their struct pages (e.g. PG_buddy). page_type overlaps with _mapcount so set the count to 0 and avoid calling page_mapcount() for these pages. [anthony.yznaga@oracle.com: incorporate feedback from Matthew Wilcox] Link: http://lkml.kernel.org/r/1544481313-27318-1-git-send-email-anthony.yznaga@oracle.com Link: http://lkml.kernel.org/r/1543963526-27917-1-git-send-email-anthony.yznaga@oracle.com Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Miles Chen <miles.chen@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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d483da5bc7 |
mm: create non-atomic version of SetPageReserved for init use
It doesn't make much sense to use the atomic SetPageReserved at init time
when we are using memset to clear the memory and manipulating the page
flags via simple "&=" and "|=" operations in __init_single_page.
This patch adds a non-atomic version __SetPageReserved that can be used
during page init and shows about a 10% improvement in initialization times
on the systems I have available for testing. On those systems I saw
initialization times drop from around 35 seconds to around 32 seconds to
initialize a 3TB block of persistent memory. I believe the main advantage
of this is that it allows for more compiler optimization as the __set_bit
operation can be reordered whereas the atomic version cannot.
I tried adding a bit of documentation based on
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f682a97a00 |
mm: provide kernel parameter to allow disabling page init poisoning
Patch series "Address issues slowing persistent memory initialization", v5. The main thing this patch set achieves is that it allows us to initialize each node worth of persistent memory independently. As a result we reduce page init time by about 2 minutes because instead of taking 30 to 40 seconds per node and going through each node one at a time, we process all 4 nodes in parallel in the case of a 12TB persistent memory setup spread evenly over 4 nodes. This patch (of 3): On systems with a large amount of memory it can take a significant amount of time to initialize all of the page structs with the PAGE_POISON_PATTERN value. I have seen it take over 2 minutes to initialize a system with over 12TB of RAM. In order to work around the issue I had to disable CONFIG_DEBUG_VM and then the boot time returned to something much more reasonable as the arch_add_memory call completed in milliseconds versus seconds. However in doing that I had to disable all of the other VM debugging on the system. In order to work around a kernel that might have CONFIG_DEBUG_VM enabled on a system that has a large amount of memory I have added a new kernel parameter named "vm_debug" that can be set to "-" in order to disable it. Link: http://lkml.kernel.org/r/20180925201921.3576.84239.stgit@localhost.localdomain Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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1899ad18c6 |
mm: workingset: tell cache transitions from workingset thrashing
Refaults happen during transitions between workingsets as well as in-place thrashing. Knowing the difference between the two has a range of applications, including measuring the impact of memory shortage on the system performance, as well as the ability to smarter balance pressure between the filesystem cache and the swap-backed workingset. During workingset transitions, inactive cache refaults and pushes out established active cache. When that active cache isn't stale, however, and also ends up refaulting, that's bonafide thrashing. Introduce a new page flag that tells on eviction whether the page has been active or not in its lifetime. This bit is then stored in the shadow entry, to classify refaults as transitioning or thrashing. How many page->flags does this leave us with on 32-bit? 20 bits are always page flags 21 if you have an MMU 23 with the zone bits for DMA, Normal, HighMem, Movable 29 with the sparsemem section bits 30 if PAE is enabled 31 with this patch. So on 32-bit PAE, that leaves 1 bit for distinguishing two NUMA nodes. If that's not enough, the system can switch to discontigmem and re-gain the 6 or 7 sparsemem section bits. Link: http://lkml.kernel.org/r/20180828172258.3185-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Drake <drake@endlessm.com> Tested-by: Suren Baghdasaryan <surenb@google.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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d4ae9916ea |
mm: soft-offline: close the race against page allocation
A process can be killed with SIGBUS(BUS_MCEERR_AR) when it tries to allocate a page that was just freed on the way of soft-offline. This is undesirable because soft-offline (which is about corrected error) is less aggressive than hard-offline (which is about uncorrected error), and we can make soft-offline fail and keep using the page for good reason like "system is busy." Two main changes of this patch are: - setting migrate type of the target page to MIGRATE_ISOLATE. As done in free_unref_page_commit(), this makes kernel bypass pcplist when freeing the page. So we can assume that the page is in freelist just after put_page() returns, - setting PG_hwpoison on free page under zone->lock which protects freelists, so this allows us to avoid setting PG_hwpoison on a page that is decided to be allocated soon. [akpm@linux-foundation.org: tweak set_hwpoison_free_buddy_page() comment] Link: http://lkml.kernel.org/r/1531452366-11661-3-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com> Tested-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <zy.zhengyi@alibaba-inc.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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1d40a5ea01 |
mm: mark pages in use for page tables
Define a new PageTable bit in the page_type and use it to mark pages in use as page tables. This can be helpful when debugging crashdumps or analysing memory fragmentation. Add a KPF flag to report these pages to userspace and update page-types.c to interpret that flag. Note that only pages currently accounted as NR_PAGETABLES are tracked as PageTable; this does not include pgd/p4d/pud/pmd pages. Those will be the subject of a later patch. Link: http://lkml.kernel.org/r/20180518194519.3820-4-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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6e292b9be7 |
mm: split page_type out from _mapcount
We're already using a union of many fields here, so stop abusing the _mapcount and make page_type its own field. That implies renaming some of the machinery that creates PageBuddy, PageBalloon and PageKmemcg; bring back the PG_buddy, PG_balloon and PG_kmemcg names. As suggested by Kirill, make page_type a bitmask. Because it starts out life as -1 (thanks to sharing the storage with _mapcount), setting a page flag means clearing the appropriate bit. This gives us space for probably twenty or so extra bits (depending how paranoid we want to be about _mapcount underflow). Link: http://lkml.kernel.org/r/20180518194519.3820-3-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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f165b378bb |
mm: uninitialized struct page poisoning sanity checking
During boot we poison struct page memory in order to ensure that no one is accessing this memory until the struct pages are initialized in __init_single_page(). This patch adds more scrutiny to this checking by making sure that flags do not equal the poison pattern when they are accessed. The pattern is all ones. Since node id is also stored in struct page, and may be accessed quite early, we add this enforcement into page_to_nid() function as well. Note, this is applicable only when NODE_NOT_IN_PAGE_FLAGS=n [pasha.tatashin@oracle.com: v4] Link: http://lkml.kernel.org/r/20180215165920.8570-4-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180213193159.14606-4-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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3f56a2f803 |
mm: remove PG_highmem description
Commit
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8745808fda |
mm, arch: remove empty_bad_page*
empty_bad_page() and empty_bad_pte_table() seem to be relics from old days which is not used by any code for a long time. I have tried to find when exactly but this is not really all that straightforward due to many code movements - traces disappear around 2.4 times. Anyway no code really references neither empty_bad_page nor empty_bad_pte_table. We only allocate the storage which is not used by anybody so remove them. Link: http://lkml.kernel.org/r/20171004150045.30755-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Ralf Baechle <ralf@linus-mips.org> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: David Howells <dhowells@redhat.com> Cc: Rich Felker <dalias@libc.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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b24413180f |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |