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Recently I messed up the error handling in filemap_fault() because of an
unexpected ENOMEM (related to cgroup memory limits) in add_to_page_cache.
Enable error injection at this point so I can add a testcase to xfstests
to verify I don't mess this up again.
[akpm@linux-foundation.org: include linux/error-injection.h]
Link: http://lkml.kernel.org/r/20190403152604.14008-1-josef@toxicpanda.com
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Helper to test if a range is updated to read only (it is still valid to
read from the range). This is useful for device driver or anyone who wish
to optimize out update when they know that they already have the range map
read only.
Link: http://lkml.kernel.org/r/20190326164747.24405-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This updates each existing invalidation to use the correct mmu notifier
event that represent what is happening to the CPU page table. See the
patch which introduced the events to see the rational behind this.
Link: http://lkml.kernel.org/r/20190326164747.24405-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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CPU page table update can happens for many reasons, not only as a result
of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as
a result of kernel activities (memory compression, reclaim, migration,
...).
Users of mmu notifier API track changes to the CPU page table and take
specific action for them. While current API only provide range of virtual
address affected by the change, not why the changes is happening.
This patchset do the initial mechanical convertion of all the places that
calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP
event as well as the vma if it is know (most invalidation happens against
a given vma). Passing down the vma allows the users of mmu notifier to
inspect the new vma page protection.
The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier
should assume that every for the range is going away when that event
happens. A latter patch do convert mm call path to use a more appropriate
events for each call.
This is done as 2 patches so that no call site is forgotten especialy
as it uses this following coccinelle patch:
%<----------------------------------------------------------------------
@@
identifier I1, I2, I3, I4;
@@
static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1,
+enum mmu_notifier_event event,
+unsigned flags,
+struct vm_area_struct *vma,
struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... }
@@
@@
-#define mmu_notifier_range_init(range, mm, start, end)
+#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end)
@@
expression E1, E3, E4;
identifier I1;
@@
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, I1,
I1->vm_mm, E3, E4)
...>
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(..., struct vm_area_struct *VMA, ...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(...) {
struct vm_area_struct *VMA;
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN;
@@
FN(...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, NULL,
E2, E3, E4)
...> }
---------------------------------------------------------------------->%
Applied with:
spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place
spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place
spatch --sp-file mmu-notifier.spatch --dir mm --in-place
Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use the mmu_notifier_range_blockable() helper function instead of directly
dereferencing the range->blockable field. This is done to make it easier
to change the mmu_notifier range field.
This patch is the outcome of the following coccinelle patch:
%<-------------------------------------------------------------------
@@
identifier I1, FN;
@@
FN(..., struct mmu_notifier_range *I1, ...) {
<...
-I1->blockable
+mmu_notifier_range_blockable(I1)
...>
}
------------------------------------------------------------------->%
spatch --in-place --sp-file blockable.spatch --dir .
Link: http://lkml.kernel.org/r/20190326164747.24405-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Convert hmm_pfn_* to device_entry_* as here we are dealing with device
driver specific entry format and hmm provide helpers to allow differents
components (including HMM) to create/parse device entry.
We keep wrapper with the old name so that we can convert driver to use the
new API in stages in each device driver tree. This will get remove once
all driver are converted.
Link: http://lkml.kernel.org/r/20190403193318.16478-13-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is a all in one helper that fault pages in a range and map them to a
device so that every single device driver do not have to re-implement this
common pattern.
This is taken from ODP RDMA in preparation of ODP RDMA convertion. It
will be use by nouveau and other drivers.
[jglisse@redhat.com: Was using wrong field and wrong enum]
Link: http://lkml.kernel.org/r/20190409175340.26614-1-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20190403193318.16478-12-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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HMM mirror is a device driver helpers to mirror range of virtual address.
It means that the process jobs running on the device can access the same
virtual address as the CPU threads of that process. This patch adds
support for mirroring mapping of file that are on a DAX block device (ie
range of virtual address that is an mmap of a file in a filesystem on a
DAX block device). There is no reason to not support such case when
mirroring virtual address on a device.
Note that unlike GUP code we do not take page reference hence when we
back-off we have nothing to undo.
[jglisse@redhat.com: move THP and hugetlbfs code path behind #if KCONFIG]
Link: http://lkml.kernel.org/r/20190422163741.13029-1-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20190403193318.16478-10-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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HMM mirror is a device driver helpers to mirror range of virtual address.
It means that the process jobs running on the device can access the same
virtual address as the CPU threads of that process. This patch adds
support for hugetlbfs mapping (ie range of virtual address that are mmap
of a hugetlbfs).
[rcampbell@nvidia.com: fix initial PFN for hugetlbfs pages]
Link: http://lkml.kernel.org/r/20190419233536.8080-1-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20190403193318.16478-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The HMM mirror API can be use in two fashions. The first one where the
HMM user coalesce multiple page faults into one request and set flags per
pfns for of those faults. The second one where the HMM user want to
pre-fault a range with specific flags. For the latter one it is a waste
to have the user pre-fill the pfn arrays with a default flags value.
This patch adds a default flags value allowing user to set them for a
range without having to pre-fill the pfn array.
Link: http://lkml.kernel.org/r/20190403193318.16478-8-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A common use case for HMM mirror is user trying to mirror a range and
before they could program the hardware it get invalidated by some core mm
event. Instead of having user re-try right away to mirror the range
provide a completion mechanism for them to wait for any active
invalidation affecting the range.
This also changes how hmm_range_snapshot() and hmm_range_fault() works by
not relying on vma so that we can drop the mmap_sem when waiting and
lookup the vma again on retry.
Link: http://lkml.kernel.org/r/20190403193318.16478-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Minor optimization around hmm_pte_need_fault(). Rename for consistency
between code, comments and documentation. Also improves the comments on
all the possible returns values. Improve the function by returning the
number of populated entries in pfns array.
Link: http://lkml.kernel.org/r/20190403193318.16478-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rename for consistency between code, comments and documentation. Also
improves the comments on all the possible returns values. Improve the
function by returning the number of populated entries in pfns array.
Link: http://lkml.kernel.org/r/20190403193318.16478-5-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Users of HMM might be using the snapshot information to do preparatory
step like dma mapping pages to a device before checking for invalidation
through hmm_vma_range_done() so do not erase that information and assume
users will do the right thing.
Link: http://lkml.kernel.org/r/20190403193318.16478-4-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Every time I read the code to check that the HMM structure does not vanish
before it should thanks to the many lock protecting its removal i get a
headache. Switch to reference counting instead it is much easier to
follow and harder to break. This also remove some code that is no longer
needed with refcounting.
Link: http://lkml.kernel.org/r/20190403193318.16478-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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To avoid random config build issue, select mmu notifier when HMM is
selected. In any cases when HMM get selected it will be by users that
will also wants the mmu notifier.
Link: http://lkml.kernel.org/r/20190403193318.16478-2-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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hugetlb uses a fault mutex hash table to prevent page faults of the
same pages concurrently. The key for shared and private mappings is
different. Shared keys off address_space and file index. Private keys
off mm and virtual address. Consider a private mappings of a populated
hugetlbfs file. A fault will map the page from the file and if needed
do a COW to map a writable page.
Hugetlbfs hole punch uses the fault mutex to prevent mappings of file
pages. It uses the address_space file index key. However, private
mappings will use a different key and could race with this code to map
the file page. This causes problems (BUG) for the page cache remove
code as it expects the page to be unmapped. A sample stack is:
page dumped because: VM_BUG_ON_PAGE(page_mapped(page))
kernel BUG at mm/filemap.c:169!
...
RIP: 0010:unaccount_page_cache_page+0x1b8/0x200
...
Call Trace:
__delete_from_page_cache+0x39/0x220
delete_from_page_cache+0x45/0x70
remove_inode_hugepages+0x13c/0x380
? __add_to_page_cache_locked+0x162/0x380
hugetlbfs_fallocate+0x403/0x540
? _cond_resched+0x15/0x30
? __inode_security_revalidate+0x5d/0x70
? selinux_file_permission+0x100/0x130
vfs_fallocate+0x13f/0x270
ksys_fallocate+0x3c/0x80
__x64_sys_fallocate+0x1a/0x20
do_syscall_64+0x5b/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9
There seems to be another potential COW issue/race with this approach
of different private and shared keys as noted in commit 8382d914ebf7
("mm, hugetlb: improve page-fault scalability").
Since every hugetlb mapping (even anon and private) is actually a file
mapping, just use the address_space index key for all mappings. This
results in potentially more hash collisions. However, this should not
be the common case.
Link: http://lkml.kernel.org/r/20190328234704.27083-3-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20190412165235.t4sscoujczfhuiyt@linux-r8p5
Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When a huge page is allocated, PagePrivate() is set if the allocation
consumed a reservation. When freeing a huge page, PagePrivate is checked.
If set, it indicates the reservation should be restored. PagePrivate
being set at free huge page time mostly happens on error paths.
When huge page reservations are created, a check is made to determine if
the mapping is associated with an explicitly mounted filesystem. If so,
pages are also reserved within the filesystem. The default action when
freeing a huge page is to decrement the usage count in any associated
explicitly mounted filesystem. However, if the reservation is to be
restored the reservation/use count within the filesystem should not be
decrementd. Otherwise, a subsequent page allocation and free for the same
mapping location will cause the file filesystem usage to go 'negative'.
Filesystem Size Used Avail Use% Mounted on
nodev 4.0G -4.0M 4.1G - /opt/hugepool
To fix, when freeing a huge page do not adjust filesystem usage if
PagePrivate() is set to indicate the reservation should be restored.
I did not cc stable as the problem has been around since reserves were
added to hugetlbfs and nobody has noticed.
Link: http://lkml.kernel.org/r/20190328234704.27083-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The code comment above sparse_add_one_section() is obsolete and incorrect.
Clean it up and write a new one.
Link: http://lkml.kernel.org/r/20190329144250.14315-1-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There is no function named munlock_vma_pages(). Correct it to
munlock_vma_page().
Link: http://lkml.kernel.org/r/20190402095609.27181-1-peng.fan@nxp.com
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
NODEMASK_ALLOC is used to allocate a nodemask bitmap, and it does it by
first determining whether it should be allocated on the stack or
dynamically, depending on NODES_SHIFT. Right now, it goes the dynamic
path whenever the nodemask_t is above 32 bytes.
Although we could bump it to a reasonable value, the largest a nodemask_t
can get is 128 bytes, so since __nr_hugepages_store_common is called from
a rather short stack we can just get rid of the NODEMASK_ALLOC call here.
This reduces some code churn and complexity.
Link: http://lkml.kernel.org/r/20190402133415.21983-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Alex Ghiti <alex@ghiti.fr>
Cc: David Rientjes <rientjes@google.com>
Cc: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The number of node specific huge pages can be set via a file such as:
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages
When a node specific value is specified, the global number of huge pages
must also be adjusted. This adjustment is calculated as the specified
node specific value + (global value - current node value). If the node
specific value provided by the user is large enough, this calculation
could overflow an unsigned long leading to a smaller than expected number
of huge pages.
To fix, check the calculation for overflow. If overflow is detected, use
ULONG_MAX as the requested value. This is inline with the user request to
allocate as many huge pages as possible.
It was also noticed that the above calculation was done outside the
hugetlb_lock. Therefore, the values could be inconsistent and result in
underflow. To fix, the calculation is moved within the routine
set_max_huge_pages() where the lock is held.
In addition, the code in __nr_hugepages_store_common() which tries to
handle the case of not being able to allocate a node mask would likely
result in incorrect behavior. Luckily, it is very unlikely we will ever
take this path. If we do, simply return ENOMEM.
Link: http://lkml.kernel.org/r/20190328220533.19884-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Alex Ghiti <alex@ghiti.fr>
Cc: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
342332e6a925 ("mm/page_alloc.c: introduce kernelcore=mirror option") and
later patches rewrote the calculation of node spanned pages.
e506b99696a2 ("mem-hotplug: fix node spanned pages when we have a movable
node"), but the current code still has problems,
When we have a node with only zone_movable and the node id is not zero,
the size of node spanned pages is double added.
That's because we have an empty normal zone, and zone_start_pfn or
zone_end_pfn is not between arch_zone_lowest_possible_pfn and
arch_zone_highest_possible_pfn, so we need to use clamp to constrain the
range just like the commit <96e907d13602> (bootmem: Reimplement
__absent_pages_in_range() using for_each_mem_pfn_range()).
e.g.
Zone ranges:
DMA [mem 0x0000000000001000-0x0000000000ffffff]
DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
Normal [mem 0x0000000100000000-0x000000023fffffff]
Movable zone start for each node
Node 0: 0x0000000100000000
Node 1: 0x0000000140000000
Early memory node ranges
node 0: [mem 0x0000000000001000-0x000000000009efff]
node 0: [mem 0x0000000000100000-0x00000000bffdffff]
node 0: [mem 0x0000000100000000-0x000000013fffffff]
node 1: [mem 0x0000000140000000-0x000000023fffffff]
node 0 DMA spanned:0xfff present:0xf9e absent:0x61
node 0 DMA32 spanned:0xff000 present:0xbefe0 absent:0x40020
node 0 Normal spanned:0 present:0 absent:0
node 0 Movable spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA spanned:0 present:0 absent:0
node 1 DMA32 spanned:0 present:0 absent:0
node 1 Normal spanned:0x100000 present:0x100000 absent:0
node 1 Movable spanned:0x100000 present:0x100000 absent:0
On node 1 totalpages(node_present_pages): 2097152
node_spanned_pages:2097152
Memory: 6967796K/12582392K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 5614596K reserved, 0K
cma-reserved)
It shows that the current memory of node 1 is double added.
After this patch, the problem is fixed.
node 0 DMA spanned:0xfff present:0xf9e absent:0x61
node 0 DMA32 spanned:0xff000 present:0xbefe0 absent:0x40020
node 0 Normal spanned:0 present:0 absent:0
node 0 Movable spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA spanned:0 present:0 absent:0
node 1 DMA32 spanned:0 present:0 absent:0
node 1 Normal spanned:0 present:0 absent:0
node 1 Movable spanned:0x100000 present:0x100000 absent:0
On node 1 totalpages(node_present_pages): 1048576
node_spanned_pages:1048576
memory: 6967796K/8388088K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 1420292K reserved, 0K
cma-reserved)
Link: http://lkml.kernel.org/r/1554178276-10372-1-git-send-email-fanglinxu@huawei.com
Signed-off-by: Linxu Fang <fanglinxu@huawei.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
template
There are three tracepoints using this template, which are
mm_vmscan_direct_reclaim_begin,
mm_vmscan_memcg_reclaim_begin,
mm_vmscan_memcg_softlimit_reclaim_begin.
Regarding mm_vmscan_direct_reclaim_begin,
sc.may_writepage is !laptop_mode, that's a static setting, and
reclaim_idx is derived from gfp_mask which is already show in this
tracepoint.
Regarding mm_vmscan_memcg_reclaim_begin,
may_writepage is !laptop_mode too, and reclaim_idx is (MAX_NR_ZONES-1),
which are both static value.
mm_vmscan_memcg_softlimit_reclaim_begin is the same with
mm_vmscan_memcg_reclaim_begin.
So we can drop them all.
Link: http://lkml.kernel.org/r/1553736322-32235-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
MADV_DONTNEED is handled with mmap_sem taken in read mode. We call
page_mkclean without holding mmap_sem.
MADV_DONTNEED implies that pages in the region are unmapped and subsequent
access to the pages in that range is handled as a new page fault. This
implies that if we don't have parallel access to the region when
MADV_DONTNEED is run we expect those range to be unallocated.
w.r.t page_mkclean() we need to make sure that we don't break the
MADV_DONTNEED semantics. MADV_DONTNEED check for pmd_none without holding
pmd_lock. This implies we skip the pmd if we temporarily mark pmd none.
Avoid doing that while marking the page clean.
Keep the sequence same for dax too even though we don't support
MADV_DONTNEED for dax mapping
The bug was noticed by code review and I didn't observe any failures w.r.t
test run. This is similar to
commit 58ceeb6bec86d9140f9d91d71a710e963523d063
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Thu Apr 13 14:56:26 2017 -0700
thp: fix MADV_DONTNEED vs. MADV_FREE race
commit ced108037c2aa542b3ed8b7afd1576064ad1362a
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Thu Apr 13 14:56:20 2017 -0700
thp: fix MADV_DONTNEED vs. numa balancing race
Link: http://lkml.kernel.org/r/20190321040610.14226-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc:"Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
A discussion of the overall problem is below.
As mentioned in patch 0001, the steps are to fix the problem are:
1) Provide put_user_page*() routines, intended to be used
for releasing pages that were pinned via get_user_pages*().
2) Convert all of the call sites for get_user_pages*(), to
invoke put_user_page*(), instead of put_page(). This involves dozens of
call sites, and will take some time.
3) After (2) is complete, use get_user_pages*() and put_user_page*() to
implement tracking of these pages. This tracking will be separate from
the existing struct page refcounting.
4) Use the tracking and identification of these pages, to implement
special handling (especially in writeback paths) when the pages are
backed by a filesystem.
Overview
========
Some kernel components (file systems, device drivers) need to access
memory that is specified via process virtual address. For a long time,
the API to achieve that was get_user_pages ("GUP") and its variations.
However, GUP has critical limitations that have been overlooked; in
particular, GUP does not interact correctly with filesystems in all
situations. That means that file-backed memory + GUP is a recipe for
potential problems, some of which have already occurred in the field.
GUP was first introduced for Direct IO (O_DIRECT), allowing filesystem
code to get the struct page behind a virtual address and to let storage
hardware perform a direct copy to or from that page. This is a
short-lived access pattern, and as such, the window for a concurrent
writeback of GUP'd page was small enough that there were not (we think)
any reported problems. Also, userspace was expected to understand and
accept that Direct IO was not synchronized with memory-mapped access to
that data, nor with any process address space changes such as munmap(),
mremap(), etc.
Over the years, more GUP uses have appeared (virtualization, device
drivers, RDMA) that can keep the pages they get via GUP for a long period
of time (seconds, minutes, hours, days, ...). This long-term pinning
makes an underlying design problem more obvious.
In fact, there are a number of key problems inherent to GUP:
Interactions with file systems
==============================
File systems expect to be able to write back data, both to reclaim pages,
and for data integrity. Allowing other hardware (NICs, GPUs, etc) to gain
write access to the file memory pages means that such hardware can dirty
the pages, without the filesystem being aware. This can, in some cases
(depending on filesystem, filesystem options, block device, block device
options, and other variables), lead to data corruption, and also to kernel
bugs of the form:
kernel BUG at /build/linux-fQ94TU/linux-4.4.0/fs/ext4/inode.c:1899!
backtrace:
ext4_writepage
__writepage
write_cache_pages
ext4_writepages
do_writepages
__writeback_single_inode
writeback_sb_inodes
__writeback_inodes_wb
wb_writeback
wb_workfn
process_one_work
worker_thread
kthread
ret_from_fork
...which is due to the file system asserting that there are still buffer
heads attached:
({ \
BUG_ON(!PagePrivate(page)); \
((struct buffer_head *)page_private(page)); \
})
Dave Chinner's description of this is very clear:
"The fundamental issue is that ->page_mkwrite must be called on every
write access to a clean file backed page, not just the first one.
How long the GUP reference lasts is irrelevant, if the page is clean
and you need to dirty it, you must call ->page_mkwrite before it is
marked writeable and dirtied. Every. Time."
This is just one symptom of the larger design problem: real filesystems
that actually write to a backing device, do not actually support
get_user_pages() being called on their pages, and letting hardware write
directly to those pages--even though that pattern has been going on since
about 2005 or so.
Long term GUP
=============
Long term GUP is an issue when FOLL_WRITE is specified to GUP (so, a
writeable mapping is created), and the pages are file-backed. That can
lead to filesystem corruption. What happens is that when a file-backed
page is being written back, it is first mapped read-only in all of the CPU
page tables; the file system then assumes that nobody can write to the
page, and that the page content is therefore stable. Unfortunately, the
GUP callers generally do not monitor changes to the CPU pages tables; they
instead assume that the following pattern is safe (it's not):
get_user_pages()
Hardware can keep a reference to those pages for a very long time,
and write to it at any time. Because "hardware" here means "devices
that are not a CPU", this activity occurs without any interaction with
the kernel's file system code.
for each page
set_page_dirty
put_page()
In fact, the GUP documentation even recommends that pattern.
Anyway, the file system assumes that the page is stable (nothing is
writing to the page), and that is a problem: stable page content is
necessary for many filesystem actions during writeback, such as checksum,
encryption, RAID striping, etc. Furthermore, filesystem features like COW
(copy on write) or snapshot also rely on being able to use a new page for
as memory for that memory range inside the file.
Corruption during write back is clearly possible here. To solve that, one
idea is to identify pages that have active GUP, so that we can use a
bounce page to write stable data to the filesystem. The filesystem would
work on the bounce page, while any of the active GUP might write to the
original page. This would avoid the stable page violation problem, but
note that it is only part of the overall solution, because other problems
remain.
Other filesystem features that need to replace the page with a new one can
be inhibited for pages that are GUP-pinned. This will, however, alter and
limit some of those filesystem features. The only fix for that would be
to require GUP users to monitor and respond to CPU page table updates.
Subsystems such as ODP and HMM do this, for example. This aspect of the
problem is still under discussion.
Direct IO
=========
Direct IO can cause corruption, if userspace does Direct-IO that writes to
a range of virtual addresses that are mmap'd to a file. The pages written
to are file-backed pages that can be under write back, while the Direct IO
is taking place. Here, Direct IO races with a write back: it calls GUP
before page_mkclean() has replaced the CPU pte with a read-only entry.
The race window is pretty small, which is probably why years have gone by
before we noticed this problem: Direct IO is generally very quick, and
tends to finish up before the filesystem gets around to do anything with
the page contents. However, it's still a real problem. The solution is
to never let GUP return pages that are under write back, but instead,
force GUP to take a write fault on those pages. That way, GUP will
properly synchronize with the active write back. This does not change the
required GUP behavior, it just avoids that race.
Details
=======
Introduces put_user_page(), which simply calls put_page(). This provides
a way to update all get_user_pages*() callers, so that they call
put_user_page(), instead of put_page().
Also introduces put_user_pages(), and a few dirty/locked variations, as a
replacement for release_pages(), and also as a replacement for open-coded
loops that release multiple pages. These may be used for subsequent
performance improvements, via batching of pages to be released.
This is the first step of fixing a problem (also described in [1] and [2])
with interactions between get_user_pages ("gup") and filesystems.
Problem description: let's start with a bug report. Below, is what
happens sometimes, under memory pressure, when a driver pins some pages
via gup, and then marks those pages dirty, and releases them. Note that
the gup documentation actually recommends that pattern. The problem is
that the filesystem may do a writeback while the pages were gup-pinned,
and then the filesystem believes that the pages are clean. So, when the
driver later marks the pages as dirty, that conflicts with the
filesystem's page tracking and results in a BUG(), like this one that I
experienced:
kernel BUG at /build/linux-fQ94TU/linux-4.4.0/fs/ext4/inode.c:1899!
backtrace:
ext4_writepage
__writepage
write_cache_pages
ext4_writepages
do_writepages
__writeback_single_inode
writeback_sb_inodes
__writeback_inodes_wb
wb_writeback
wb_workfn
process_one_work
worker_thread
kthread
ret_from_fork
...which is due to the file system asserting that there are still buffer
heads attached:
({ \
BUG_ON(!PagePrivate(page)); \
((struct buffer_head *)page_private(page)); \
})
Dave Chinner's description of this is very clear:
"The fundamental issue is that ->page_mkwrite must be called on
every write access to a clean file backed page, not just the first
one. How long the GUP reference lasts is irrelevant, if the page is
clean and you need to dirty it, you must call ->page_mkwrite before it
is marked writeable and dirtied. Every. Time."
This is just one symptom of the larger design problem: real filesystems
that actually write to a backing device, do not actually support
get_user_pages() being called on their pages, and letting hardware write
directly to those pages--even though that pattern has been going on since
about 2005 or so.
The steps are to fix it are:
1) (This patch): provide put_user_page*() routines, intended to be used
for releasing pages that were pinned via get_user_pages*().
2) Convert all of the call sites for get_user_pages*(), to
invoke put_user_page*(), instead of put_page(). This involves dozens of
call sites, and will take some time.
3) After (2) is complete, use get_user_pages*() and put_user_page*() to
implement tracking of these pages. This tracking will be separate from
the existing struct page refcounting.
4) Use the tracking and identification of these pages, to implement
special handling (especially in writeback paths) when the pages are
backed by a filesystem.
[1] https://lwn.net/Articles/774411/ : "DMA and get_user_pages()"
[2] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()"
Link: http://lkml.kernel.org/r/20190327023632.13307-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> [docs]
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
On systems without CONTIG_ALLOC activated but that support gigantic pages,
boottime reserved gigantic pages can not be freed at all. This patch
simply enables the possibility to hand back those pages to memory
allocator.
Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: David S. Miller <davem@davemloft.net> [sparc]
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This condition allows to define alloc_contig_range, so simplify it into a
more accurate naming.
Link: http://lkml.kernel.org/r/20190327063626.18421-4-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
f022d8cb7ec7 ("mm: cma: Don't crash on allocation if CMA area can't be
activated") fixes the crash issue when activation fails via setting
cma->count as 0, same logic exists if bitmap allocation fails.
Link: http://lkml.kernel.org/r/20190325081309.6004-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.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>
|
|
Only memcg_numa_stat_show() uses those wrappers and the lru bitmasks,
group them together.
Link: http://lkml.kernel.org/r/20190228163020.24100-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
mem_cgroup_nr_lru_pages() is just a convenience wrapper around
memcg_page_state() that takes bitmasks of lru indexes and aggregates the
counts for those.
Replace callsites where the bitmask is simple enough with direct
memcg_page_state() call(s).
Link: http://lkml.kernel.org/r/20190228163020.24100-6-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
mem_cgroup_node_nr_lru_pages() is just a convenience wrapper around
lruvec_page_state() that takes bitmasks of lru indexes and aggregates the
counts for those.
Replace callsites where the bitmask is simple enough with direct
lruvec_page_state() calls.
This removes the last extern user of mem_cgroup_node_nr_lru_pages(), so
make that function private again, too.
Link: http://lkml.kernel.org/r/20190228163020.24100-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Instead of adding up the node counters, use memcg_page_state() to get the
memcg state directly. This is a bit cheaper and more stream-lined.
Link: http://lkml.kernel.org/r/20190228163020.24100-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Instead of adding up the zone counters, use lruvec_page_state() to get the
node state directly. This is a bit cheaper and more stream-lined.
Link: http://lkml.kernel.org/r/20190228163020.24100-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The page alloc fast path it may perform node reclaim, which may cause a
latency spike. We should add tracepoint for this event, and also measure
the latency it causes.
So bellow two tracepoints are introduced,
mm_vmscan_node_reclaim_begin
mm_vmscan_node_reclaim_end
Link: http://lkml.kernel.org/r/1551421452-5385-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: <shaoyafang@didiglobal.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
pfn_valid_within() calls pfn_valid() when CONFIG_HOLES_IN_ZONE making it
redundant for both definitions (w/wo CONFIG_MEMORY_HOTPLUG) of the helper
pfn_to_online_page() which either calls pfn_valid() or pfn_valid_within().
pfn_valid_within() being 1 when !CONFIG_HOLES_IN_ZONE is irrelevant
either way. This does not change functionality.
Link: http://lkml.kernel.org/r/1553141595-26907-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.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>
|
|
Currently one bit in cma bitmap represents number of pages rather than
one page, cma->count means cma size in pages. So to find available pages
via find_next_zero_bit()/find_next_bit() we should use cma size not in
pages but in bits although current free pages number is correct due to
zero value of order_per_bit. Once order_per_bit is changed the bitmap
status will be incorrect.
The size input in cma_debug_show_areas() is not correct. It will
affect the available pages at some position to debug the failure issue.
This is an example with order_per_bit = 1
Before this change:
[ 4.120060] cma: number of available pages: 1@93+4@108+7@121+7@137+7@153+7@169+7@185+7@201+3@213+3@221+3@229+3@237+3@245+3@253+3@261+3@269+3@277+3@285+3@293+3@301+3@309+3@317+3@325+19@333+15@369+512@512=> 638 free of 1024 total pages
After this change:
[ 4.143234] cma: number of available pages: 2@93+8@108+14@121+14@137+14@153+14@169+14@185+14@201+6@213+6@221+6@229+6@237+6@245+6@253+6@261+6@269+6@277+6@285+6@293+6@301+6@309+6@317+6@325+38@333+30@369=> 252 free of 1024 total pages
Obviously the bitmap status before is incorrect.
Link: http://lkml.kernel.org/r/20190320060829.9144-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Laura Abbott <labbott@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
In a low-memory situation, cc->fast_search_fail can keep increasing as it
is unable to find an available page to isolate in
fast_isolate_freepages(). As the result, it could trigger an error below,
so just compare with the maximum bits can be shifted first.
UBSAN: Undefined behaviour in mm/compaction.c:1160:30
shift exponent 64 is too large for 64-bit type 'unsigned long'
CPU: 131 PID: 1308 Comm: kcompactd1 Kdump: loaded Tainted: G
W L 5.0.0+ #17
Call trace:
dump_backtrace+0x0/0x450
show_stack+0x20/0x2c
dump_stack+0xc8/0x14c
__ubsan_handle_shift_out_of_bounds+0x7e8/0x8c4
compaction_alloc+0x2344/0x2484
unmap_and_move+0xdc/0x1dbc
migrate_pages+0x274/0x1310
compact_zone+0x26ec/0x43bc
kcompactd+0x15b8/0x1a24
kthread+0x374/0x390
ret_from_fork+0x10/0x18
[akpm@linux-foundation.org: code cleanup]
Link: http://lkml.kernel.org/r/20190320203338.53367-1-cai@lca.pw
Fixes: 70b44595eafe ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
In node_states_check_changes_online(), N_HIGH_MEMORY is used to substitute
ZONE_HIGHMEM directly. This is not right. N_HIGH_MEMORY is to mark the
memory state of node. Here zone index is checked, which should be
compared with 'ZONE_HIGHMEM' accordingly.
Replace it with ZONE_HIGHMEM.
This is a code cleanup - no known runtime effects.
Link: http://lkml.kernel.org/r/20190320080732.14933-1-bhe@redhat.com
Fixes: 8efe33f40f3e ("mm/memory_hotplug.c: simplify node_states_check_changes_online")
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
has_unmovable_pages() already checks whether the hugetlb page supports
migration, so all non-migratable hugetlb pages should have been caught
there. Let us drop the check from scan_movable_pages() as is redundant.
Link: http://lkml.kernel.org/r/20190320152658.10855-3-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.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>
|
|
On x86_64, 1GB-hugetlb pages could never be offlined due to the fact
that hugepage_migration_supported() returned false for PUD_SHIFT.
So whenever we wanted to offline a memblock containing a gigantic
hugetlb page, we never got beyond has_unmovable_pages() check.
This changed with [1], where now we also return true for PUD_SHIFT.
After that patch, the check in has_unmovable_pages() and scan_movable_pages()
returned true, but we still had a final barrier in do_migrate_range():
if (compound_order(head) > PFN_SECTION_SHIFT) {
ret = -EBUSY;
break;
}
This is not really nice, and we do not really need it.
It is perfectly possible to migrate a gigantic page as long as another node has
a spare gigantic page for us.
In alloc_huge_page_nodemask(), we calculate the __real__ number of free pages,
and if any, we try to dequeue one from another node.
This all works fine when we do have another node with a spare gigantic page,
but if that is not the case, alloc_huge_page_nodemask() ends up calling
alloc_migrate_huge_page() which bails out if the wanted page is gigantic.
That is mainly because finding a 1GB (or even 16GB on powerpc) contiguous
memory is quite unlikely when the system has been running for a while.
In that situation, we will keep looping forever because scan_movable_pages()
will give us the same page and we will fail again because there is no node
where we can dequeue a gigantic page from.
This is not nice, and it has been raised that we might want to treat -ENOMEM
as a fatal error in do_migrate_range(), but this has to be checked further.
Anyway, I would tend say that this is the administrator's job, to make sure
that the system can keep up with the memory to be offlined, so that would mean
that if we want to use gigantic pages, make sure that the other nodes have at
least enough gigantic pages to keep up in case we need to offline memory.
Just for the sake of completeness, this is one of the tests done:
# echo 1 > /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages
# echo 1 > /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/nr_hugepages
# cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages
1
# cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/free_hugepages
1
# cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/nr_hugepages
1
# cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages
1
(hugetlb1gb is a program that maps 1GB region using MAP_HUGE_1GB)
# numactl -m 1 ./hugetlb1gb
# cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/free_hugepages
0
# cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages
1
# offline node1 memory
# cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages
0
[1] https://lore.kernel.org/patchwork/patch/998796/
Link: http://lkml.kernel.org/r/20190320152658.10855-2-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.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>
|
|
DAX pages were previously unprotected from longterm pins when users called
get_user_pages_fast().
Use the new FOLL_LONGTERM flag to check for DEVMAP pages and fall back to
regular GUP processing if a DEVMAP page is encountered.
[ira.weiny@intel.com: v3]
Link: http://lkml.kernel.org/r/20190328084422.29911-5-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190328084422.29911-5-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-5-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
To facilitate additional options to get_user_pages_fast() change the
singular write parameter to be gup_flags.
This patch does not change any functionality. New functionality will
follow in subsequent patches.
Some of the get_user_pages_fast() call sites were unchanged because they
already passed FOLL_WRITE or 0 for the write parameter.
NOTE: It was suggested to change the ordering of the get_user_pages_fast()
arguments to ensure that callers were converted. This breaks the current
GUP call site convention of having the returned pages be the final
parameter. So the suggestion was rejected.
Link: http://lkml.kernel.org/r/20190328084422.29911-4-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-4-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Mike Marshall <hubcap@omnibond.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
In order to support more options in the GUP fast walk, change the write
parameter to flags throughout the call stack.
This patch does not change functionality and passes FOLL_WRITE where write
was previously used.
Link: http://lkml.kernel.org/r/20190328084422.29911-3-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-3-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Pach series "Add FOLL_LONGTERM to GUP fast and use it".
HFI1, qib, and mthca, use get_user_pages_fast() due to its performance
advantages. These pages can be held for a significant time. But
get_user_pages_fast() does not protect against mapping FS DAX pages.
Introduce FOLL_LONGTERM and use this flag in get_user_pages_fast() which
retains the performance while also adding the FS DAX checks. XDP has also
shown interest in using this functionality.[1]
In addition we change get_user_pages() to use the new FOLL_LONGTERM flag
and remove the specialized get_user_pages_longterm call.
[1] https://lkml.org/lkml/2019/3/19/939
"longterm" is a relative thing and at this point is probably a misnomer.
This is really flagging a pin which is going to be given to hardware and
can't move. I've thought of a couple of alternative names but I think we
have to settle on if we are going to use FL_LAYOUT or something else to
solve the "longterm" problem. Then I think we can change the flag to a
better name.
Secondly, it depends on how often you are registering memory. I have
spoken with some RDMA users who consider MR in the performance path...
For the overall application performance. I don't have the numbers as the
tests for HFI1 were done a long time ago. But there was a significant
advantage. Some of which is probably due to the fact that you don't have
to hold mmap_sem.
Finally, architecturally I think it would be good for everyone to use
*_fast. There are patches submitted to the RDMA list which would allow
the use of *_fast (they reworking the use of mmap_sem) and as soon as they
are accepted I'll submit a patch to convert the RDMA core as well. Also
to this point others are looking to use *_fast.
As an aside, Jasons pointed out in my previous submission that *_fast and
*_unlocked look very much the same. I agree and I think further cleanup
will be coming. But I'm focused on getting the final solution for DAX at
the moment.
This patch (of 7):
This patch starts a series which aims to support FOLL_LONGTERM in
get_user_pages_fast(). Some callers who would like to do a longterm (user
controlled pin) of pages with the fast variant of GUP for performance
purposes.
Rather than have a separate get_user_pages_longterm() call, introduce
FOLL_LONGTERM and change the longterm callers to use it.
This patch does not change any functionality. In the short term
"longterm" or user controlled pins are unsafe for Filesystems and FS DAX
in particular has been blocked. However, callers of get_user_pages_fast()
were not "protected".
FOLL_LONGTERM can _only_ be supported with get_user_pages[_fast]() as it
requires vmas to determine if DAX is in use.
NOTE: In merging with the CMA changes we opt to change the
get_user_pages() call in check_and_migrate_cma_pages() to a call of
__get_user_pages_locked() on the newly migrated pages. This makes the
code read better in that we are calling __get_user_pages_locked() on the
pages before and after a potential migration.
As a side affect some of the interfaces are cleaned up but this is not the
primary purpose of the series.
In review[1] it was asked:
<quote>
> This I don't get - if you do lock down long term mappings performance
> of the actual get_user_pages call shouldn't matter to start with.
>
> What do I miss?
A couple of points.
First "longterm" is a relative thing and at this point is probably a
misnomer. This is really flagging a pin which is going to be given to
hardware and can't move. I've thought of a couple of alternative names
but I think we have to settle on if we are going to use FL_LAYOUT or
something else to solve the "longterm" problem. Then I think we can
change the flag to a better name.
Second, It depends on how often you are registering memory. I have spoken
with some RDMA users who consider MR in the performance path... For the
overall application performance. I don't have the numbers as the tests
for HFI1 were done a long time ago. But there was a significant
advantage. Some of which is probably due to the fact that you don't have
to hold mmap_sem.
Finally, architecturally I think it would be good for everyone to use
*_fast. There are patches submitted to the RDMA list which would allow
the use of *_fast (they reworking the use of mmap_sem) and as soon as they
are accepted I'll submit a patch to convert the RDMA core as well. Also
to this point others are looking to use *_fast.
As an asside, Jasons pointed out in my previous submission that *_fast and
*_unlocked look very much the same. I agree and I think further cleanup
will be coming. But I'm focused on getting the final solution for DAX at
the moment.
</quote>
[1] https://lore.kernel.org/lkml/20190220180255.GA12020@iweiny-DESK2.sc.intel.com/T/#md6abad2569f3bf6c1f03686c8097ab6563e94965
[ira.weiny@intel.com: v3]
Link: http://lkml.kernel.org/r/20190328084422.29911-2-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190328084422.29911-2-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-2-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This combines two similar functions move_active_pages_to_lru() and
putback_inactive_pages() into single move_pages_to_lru(). This remove
duplicate code and makes object file size smaller.
Before:
text data bss dec hex filename
57082 4732 128 61942 f1f6 mm/vmscan.o
After:
text data bss dec hex filename
55112 4600 128 59840 e9c0 mm/vmscan.o
Note, that now we are checking for !page_evictable() coming from
shrink_active_list(), which shouldn't change any behavior since that path
works with evictable pages only.
Link: http://lkml.kernel.org/r/155290129627.31489.8321971028677203248.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
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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We may use input argument list as output argument too. This makes the
function more similar to putback_inactive_pages().
Link: http://lkml.kernel.org/r/155290129079.31489.16180612694090502942.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
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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We know which LRU is not active.
[chris@chrisdown.name: fix build on !CONFIG_MEMCG]
Link: http://lkml.kernel.org/r/20190322150513.GA22021@chrisdown.name
Link: http://lkml.kernel.org/r/155290128498.31489.18250485448913338607.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
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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Patch series "mm: Generalize putback functions"]
putback_inactive_pages() and move_active_pages_to_lru() are almost
similar, so this patchset merges them ina single function.
This patch (of 4):
The patch moves the calculation from putback_inactive_pages() to
shrink_inactive_list(). This makes putback_inactive_pages() looking more
similar to move_active_pages_to_lru().
To do that, we account activated pages in reclaim_stat::nr_activate.
Since a page may change its LRU type from anon to file cache inside
shrink_page_list() (see ClearPageSwapBacked()), we have to account pages
for the both types. So, nr_activate becomes an array.
Previously we used nr_activate to account PGACTIVATE events, but now we
account them into pgactivate variable (since they are about number of
pages in general, not about sum of hpage_nr_pages).
Link: http://lkml.kernel.org/r/155290127956.31489.3393586616054413298.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
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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alloc_pages_exact*() allocates a page of sufficient order and then splits
it to return only the number of pages requested. That makes it
incompatible with __GFP_COMP, because compound pages cannot be split.
As shown by [1] things may silently work until the requested size
(possibly depending on user) stops being power of two. Then for
CONFIG_DEBUG_VM, BUG_ON() triggers in split_page(). Without
CONFIG_DEBUG_VM, consequences are unclear.
There are several options here, none of them great:
1) Don't do the splitting when __GFP_COMP is passed, and return the
whole compound page. However if caller then returns it via
free_pages_exact(), that will be unexpected and the freeing actions
there will be wrong.
2) Warn and remove __GFP_COMP from the flags. But the caller may have
really wanted it, so things may break later somewhere.
3) Warn and return NULL. However NULL may be unexpected, especially
for small sizes.
This patch picks option 2, because as Michal Hocko put it: "callers wanted
it" is much less probable than "caller is simply confused and more gfp
flags is surely better than fewer".
[1] https://lore.kernel.org/lkml/20181126002805.GI18977@shao2-debian/T/#u
Link: http://lkml.kernel.org/r/0c6393eb-b28d-4607-c386-862a71f09de6@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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