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MADVISE_WILLNEED has always been a noop for DAX (formerly XIP) mappings.
Unfortunately madvise_willneed() doesn't communicate this information
properly to the generic madvise syscall implementation. The calling
convention is quite subtle there. madvise_vma() is supposed to either
return an error or update &prev otherwise the main loop will never
advance to the next vma and it will keep looping for ever without a way
to get out of the kernel.
It seems this has been broken since introduction. Nobody has noticed
because nobody seems to be using MADVISE_WILLNEED on these DAX mappings.
[[email protected]: rewrite changelog]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: fe77ba6f4f97 ("[PATCH] xip: madvice/fadvice: execute in place")
Signed-off-by: chenjie <[email protected]>
Signed-off-by: guoxuenan <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: zhangyi (F) <[email protected]>
Cc: Miao Xie <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Carsten Otte <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Until there is a solution to the dma-to-dax vs truncate problem it is
not safe to allow V4L2, Exynos, and other frame vector users to create
long standing / irrevocable memory registrations against filesytem-dax
vmas.
[[email protected]: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan]
Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com
Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: Seung-Woo Kim <[email protected]>
Cc: Joonyoung Shim <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Doug Ledford <[email protected]>
Cc: Hal Rosenstock <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Sean Hefty <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Patch series "introduce get_user_pages_longterm()", v2.
Here is a new get_user_pages api for cases where a driver intends to
keep an elevated page count indefinitely. This is distinct from usages
like iov_iter_get_pages where the elevated page counts are transient.
The iov_iter_get_pages cases immediately turn around and submit the
pages to a device driver which will put_page when the i/o operation
completes (under kernel control).
In the longterm case userspace is responsible for dropping the page
reference at some undefined point in the future. This is untenable for
filesystem-dax case where the filesystem is in control of the lifetime
of the block / page and needs reasonable limits on how long it can wait
for pages in a mapping to become idle.
Fixing filesystems to actually wait for dax pages to be idle before
blocks from a truncate/hole-punch operation are repurposed is saved for
a later patch series.
Also, allowing longterm registration of dax mappings is a future patch
series that introduces a "map with lease" semantic where the kernel can
revoke a lease and force userspace to drop its page references.
I have also tagged these for -stable to purposely break cases that might
assume that longterm memory registrations for filesystem-dax mappings
were supported by the kernel. The behavior regression this policy
change implies is one of the reasons we maintain the "dax enabled.
Warning: EXPERIMENTAL, use at your own risk" notification when mounting
a filesystem in dax mode.
It is worth noting the device-dax interface does not suffer the same
constraints since it does not support file space management operations
like hole-punch.
This patch (of 4):
Until there is a solution to the dma-to-dax vs truncate problem it is
not safe to allow long standing memory registrations against
filesytem-dax vmas. Device-dax vmas do not have this problem and are
explicitly allowed.
This is temporary until a "memory registration with layout-lease"
mechanism can be implemented for the affected sub-systems (RDMA and
V4L2).
[[email protected]: use kcalloc()]
Link: http://lkml.kernel.org/r/151068939435.7446.13560129395419350737.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <[email protected]>
Suggested-by: Christoph Hellwig <[email protected]>
Cc: Doug Ledford <[email protected]>
Cc: Hal Rosenstock <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Joonyoung Shim <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Sean Hefty <[email protected]>
Cc: Seung-Woo Kim <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Patch series "device-dax: fix unaligned munmap handling"
When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and fail attempts to split vmas into unaligned ranges. It
would be messy to teach the munmap path about device-dax alignment
constraints in the same (hstate) way that hugetlbfs communicates this
constraint. Instead, these patches introduce a new ->split() vm
operation.
This patch (of 2):
The device-dax interface has similar constraints as hugetlbfs in that it
requires the munmap path to unmap in huge page aligned units. Rather
than add more custom vma handling code in __split_vma() introduce a new
vm operation to perform this vma specific check.
Link: http://lkml.kernel.org/r/151130418135.4029.6783191281930729710.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:
- validate that the mapping is writable from a protection keys
standpoint
- validate that the pte has _PAGE_USER set since all fault paths where
pte_write is must be referencing user-memory.
Link: http://lkml.kernel.org/r/151043111604.2842.8051684481794973100.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: "Jérôme Glisse" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:
- validate that the mapping is writable from a protection keys
standpoint
- validate that the pte has _PAGE_USER set since all fault paths where
pmd_write is must be referencing user-memory.
Link: http://lkml.kernel.org/r/151043111049.2842.15241454964150083466.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: "Jérôme Glisse" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:
- validate that the mapping is writable from a protection keys
standpoint
- validate that the pte has _PAGE_USER set since all fault paths where
pud_write is must be referencing user-memory.
[[email protected]: fix powerpc compile error]
Link: http://lkml.kernel.org/r/151129127237.37405.16073414520854722485.stgit@dwillia2-desk3.amr.corp.intel.com
Link: http://lkml.kernel.org/r/151043110453.2842.2166049702068628177.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If the call __alloc_contig_migrate_range() in alloc_contig_range returns
-EBUSY, processing continues so that test_pages_isolated() is called
where there is a tracepoint to identify the busy pages. However, it is
possible for busy pages to become available between the calls to these
two routines. In this case, the range of pages may be allocated.
Unfortunately, the original return code (ret == -EBUSY) is still set and
returned to the caller. Therefore, the caller believes the pages were
not allocated and they are leaked.
Update the comment to indicate that allocation is still possible even if
__alloc_contig_migrate_range returns -EBUSY. Also, clear return code in
this case so that it is not accidentally used or returned to caller.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 8ef5849fa8a2 ("mm/cma: always check which page caused allocation failure")
Signed-off-by: Mike Kravetz <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Joonsoo Kim <[email protected]>
Cc: Michal Nazarewicz <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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tlb_gather_mmu(&tlb, mm, 0, -1) means gathering the whole virtual memory
space. In this case, tlb->fullmm is true. Some archs like arm64
doesn't flush TLB when tlb->fullmm is true:
commit 5a7862e83000 ("arm64: tlbflush: avoid flushing when fullmm == 1").
Which causes leaking of tlb entries.
Will clarifies his patch:
"Basically, we tag each address space with an ASID (PCID on x86) which
is resident in the TLB. This means we can elide TLB invalidation when
pulling down a full mm because we won't ever assign that ASID to
another mm without doing TLB invalidation elsewhere (which actually
just nukes the whole TLB).
I think that means that we could potentially not fault on a kernel
uaccess, because we could hit in the TLB"
There could be a window between complete_signal() sending IPI to other
cores and all threads sharing this mm are really kicked off from cores.
In this window, the oom reaper may calls tlb_flush_mmu_tlbonly() to
flush TLB then frees pages. However, due to the above problem, the TLB
entries are not really flushed on arm64. Other threads are possible to
access these pages through TLB entries. Moreover, a copy_to_user() can
also write to these pages without generating page fault, causes
use-after-free bugs.
This patch gathers each vma instead of gathering full vm space. In this
case tlb->fullmm is not true. The behavior of oom reaper become similar
to munmapping before do_exit, which should be safe for all archs.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: aac453635549 ("mm, oom: introduce oom reaper")
Signed-off-by: Wang Nan <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Bob Liu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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drain_all_pages backs off when called from a kworker context since
commit 0ccce3b92421 ("mm, page_alloc: drain per-cpu pages from workqueue
context") because the original IPI based pcp draining has been replaced
by a WQ based one and the check wanted to prevent from recursion and
inter workers dependencies. This has made some sense at the time
because the system WQ has been used and one worker holding the lock
could be blocked while waiting for new workers to emerge which can be a
problem under OOM conditions.
Since then commit ce612879ddc7 ("mm: move pcp and lru-pcp draining into
single wq") has moved draining to a dedicated (mm_percpu_wq) WQ with a
rescuer so we shouldn't depend on any other WQ activity to make a
forward progress so calling drain_all_pages from a worker context is
safe as long as this doesn't happen from mm_percpu_wq itself which is
not the case because all workers are required to _not_ depend on any MM
locks.
Why is this a problem in the first place? ACPI driven memory hot-remove
(acpi_device_hotplug) is executed from the worker context. We end up
calling __offline_pages to free all the pages and that requires both
lru_add_drain_all_cpuslocked and drain_all_pages to do their job
otherwise we can have dangling pages on pcp lists and fail the offline
operation (__test_page_isolated_in_pageblock would see a page with 0 ref
count but without PageBuddy set).
Fix the issue by removing the worker check in drain_all_pages.
lru_add_drain_all_cpuslocked doesn't have this restriction so it works
as expected.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 0ccce3b924212 ("mm, page_alloc: drain per-cpu pages from workqueue context")
Signed-off-by: Michal Hocko <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: <[email protected]> [4.11+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pull printk pointer hashing update from Tobin Harding:
"Here is the patch set that implements hashing of printk specifier %p.
First we have two clean up patches then we do the hashing. Hashing is
done via the SipHash algorithm. The next patch adds printk specifier
%px for printing pointers when we _really_ want to see the address i.e
%px is functionally equivalent to %lx. Final patch in the set fixes
KASAN since we break it by hashing %p.
For the record here is the justification for the series:
Currently there exist approximately 14 000 places in the Kernel
where addresses are being printed using an unadorned %p. This
potentially leaks sensitive information about the Kernel layout in
memory. Many of these calls are stale, instead of fixing every call
we hash the address by default before printing. We then add %px to
provide a way to print the actual address. Although this is
achievable using %lx, using %px will assist us if we ever want to
change pointer printing behaviour. %px is more uniquely grep'able
(there are already >50 000 uses of %lx).
The added advantage of hashing %p is that security is now opt-out,
if you _really_ want the address you have to work a little harder
and use %px.
This will of course break some users, forcing code printing needed
addresses to be updated"
[ I do expect this to be an annoyance, and a number of %px users to be
added for debuggability. But nobody is willing to audit existing %p
users for information leaks, and a number of places really only use
the pointer as an object identifier rather than really 'I need the
address'.
IOW - sorry for the inconvenience, but it's the least inconvenient of
the options. - Linus ]
* tag 'printk-hash-pointer-4.15-rc2' of git://github.com/tcharding/linux:
kasan: use %px to print addresses instead of %p
vsprintf: add printk specifier %px
printk: hash addresses printed with %p
vsprintf: refactor %pK code out of pointer()
docs: correct documentation for %pK
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This reverts commit 152e93af3cfe2d29d8136cc0a02a8612507136ee.
It was a nice cleanup in theory, but as Nicolai Stange points out, we do
need to make the page dirty for the copy-on-write case even when we
didn't end up making it writable, since the dirty bit is what we use to
check that we've gone through a COW cycle.
Reported-by: Michal Hocko <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pointers printed with %p are now hashed by default. Kasan needs the
actual address. We can use the new printk specifier %px for this
purpose.
Use %px instead of %p to print addresses.
Signed-off-by: Tobin C. Harding <[email protected]>
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Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs(). This
commit therefore makes this change.
Signed-off-by: Paul E. McKenney <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Vlastimil Babka <[email protected]>
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Signed-off-by: Al Viro <[email protected]>
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__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that __poll_t value.
Signed-off-by: Al Viro <[email protected]>
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This is a pure automated search-and-replace of the internal kernel
superblock flags.
The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.
Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.
The script to do this was:
# places to look in; re security/*: it generally should *not* be
# touched (that stuff parses mount(2) arguments directly), but
# there are two places where we really deal with superblock flags.
FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
include/linux/fs.h include/uapi/linux/bfs_fs.h \
security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
# the list of MS_... constants
SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
ACTIVE NOUSER"
SED_PROG=
for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done
# we want files that contain at least one of MS_...,
# with fs/namespace.c and fs/pnode.c excluded.
L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')
for f in $L; do sed -i $f $SED_PROG; done
Requested-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit 438a506180 ("percpu: don't forget to free the temporary struct
pcpu_alloc_info") uncovered a problem on the CRIS architecture where
the bootmem allocator is initialized with virtual addresses. Given it
has:
#define __va(x) ((void *)((unsigned long)(x) | 0x80000000))
then things just work out because the end result is the same whether you
give this a physical or a virtual address.
Untill you call memblock_free_early(__pa(address)) that is, because
values from __pa() don't match with the virtual addresses stuffed in the
bootmem allocator anymore.
Avoid freeing the temporary pcpu_alloc_info memory on that architecture
until they fix things up to let the kernel boot like it did before.
Signed-off-by: Nicolas Pitre <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Fixes: 438a506180 ("percpu: don't forget to free the temporary struct pcpu_alloc_info")
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Currently we make page table entries dirty all the time regardless of
access type and don't even consider if the mapping is write-protected.
The reasoning is that we don't really need dirty tracking on THP and
making the entry dirty upfront may save some time on first write to the
page.
Unfortunately, such approach may result in false-positive
can_follow_write_pmd() for huge zero page or read-only shmem file.
Let's only make page dirty only if we about to write to the page anyway
(as we do for small pages).
I've restructured the code to make entry dirty inside
maybe_p[mu]d_mkwrite(). It also takes into account if the vma is
write-protected.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Currently, we unconditionally make page table dirty in touch_pmd().
It may result in false-positive can_follow_write_pmd().
We may avoid the situation, if we would only make the page table entry
dirty if caller asks for write access -- FOLL_WRITE.
The patch also changes touch_pud() in the same way.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.
Cc: Jens Axboe <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
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In order to make error handle more cleaner we call bdi_debug_register
before set state to WB_registered, that we can avoid call bdi_unregister
in release_bdi().
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: weiping zhang <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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Convert bdi_debug_register to int and then do error handle for it.
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: weiping zhang <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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Performance of get_user_pages_fast() is critical for some workloads, but
it's tricky to test it directly.
This patch provides /sys/kernel/debug/gup_benchmark that helps with
testing performance of it.
See tools/testing/selftests/vm/gup_benchmark.c for userspace
counterpart.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Kirill A. Shutemov <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thorsten Leemhuis <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Huang Ying <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit f3c931633a59 ("mm, compaction: persistently skip hugetlbfs
pageblocks") has introduced pageblock_skip_persistent() checks into
migration and free scanners, to make sure pageblocks that should be
persistently skipped are marked as such, regardless of the
ignore_skip_hint flag.
Since the previous patch introduced a new no_set_skip_hint flag, the
ignore flag no longer prevents marking pageblocks as skipped. Therefore
we can remove the special cases. The relevant pageblocks will be marked
as skipped by the common logic which marks each pageblock where no page
could be isolated. This makes the code simpler.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pageblock skip hints were added as a heuristic for compaction, which
shares core code with CMA. Since CMA reliability would suffer from the
heuristics, compact_control flag ignore_skip_hint was added for the CMA
use case. Since 6815bf3f233e ("mm/compaction: respect ignore_skip_hint
in update_pageblock_skip") the flag also means that CMA won't *update*
the skip hints in addition to ignoring them.
Today, direct compaction can also ignore the skip hints in the last
resort attempt, but there's no reason not to set them when isolation
fails in such case. Thus, this patch splits off a new no_set_skip_hint
flag to avoid the updating, which only CMA sets. This should improve
the heuristics a bit, and allow us to simplify the persistent skip bit
handling as the next step.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
pageblock_skip_persistent() checks for HugeTLB pages of pageblock order.
When clearing pageblock skip bits for compaction, the bits are not
cleared for such pageblocks, because they cannot contain base pages
suitable for migration, nor free pages to use as migration targets.
This optimization can be simply extended to all compound pages of order
equal or larger than pageblock order, because migrating such pages (if
they support it) cannot help sub-pageblock fragmentation. This includes
THP's and also gigantic HugeTLB pages, which the current implementation
doesn't persistently skip due to a strict pageblock_order equality check
and not recognizing tail pages.
While THP pages are generally less "persistent" than HugeTLB, we can
still expect that if a THP exists at the point of
__reset_isolation_suitable(), it will exist also during the subsequent
compaction run. The time difference here could be actually smaller than
between a compaction run that sets a (non-persistent) skip bit on a THP,
and the next compaction run that observes it.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
It is pointless to migrate hugetlb memory as part of memory compaction
if the hugetlb size is equal to the pageblock order. No defragmentation
is occurring in this condition.
It is also pointless to for the freeing scanner to scan a pageblock
where a hugetlb page is pinned. Unconditionally skip these pageblocks,
and do so peristently so that they are not rescanned until it is
observed that these hugepages are no longer pinned.
It would also be possible to do this by involving the hugetlb subsystem
in marking pageblocks to no longer be skipped when they hugetlb pages
are freed. This is a simple solution that doesn't involve any
additional subsystems in pageblock skip manipulation.
[[email protected]: fix build]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Rientjes <[email protected]>
Tested-by: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Kcompactd is needlessly ignoring pageblock skip information. It is
doing MIGRATE_SYNC_LIGHT compaction, which is no more powerful than
MIGRATE_SYNC compaction.
If compaction recently failed to isolate memory from a set of
pageblocks, there is nothing to indicate that kcompactd will be able to
do so, or that it is beneficial from attempting to isolate memory.
Use the pageblock skip hint to avoid rescanning pageblocks needlessly
until that information is reset.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Rientjes <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Fix the following warning by removing the unused variable:
mm/shmem.c:3205:27: warning: variable 'info' set but not used [-Wunused-but-set-variable]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Corentin Labbe <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
There is a race in the current z3fold implementation between
do_compact() called in a work queue context and the page release
procedure when page's kref goes to 0.
do_compact() may be waiting for page lock, which is released by
release_z3fold_page_locked right before putting the page onto the
"stale" list, and then the page may be freed as do_compact() modifies
its contents.
The mechanism currently implemented to handle that (checking the
PAGE_STALE flag) is not reliable enough. Instead, we'll use page's kref
counter to guarantee that the page is not released if its compaction is
scheduled. It then becomes compaction function's responsibility to
decrease the counter and quit immediately if the page was actually
freed.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vitaly Wool <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm and dax updates from Dan Williams:
"Save for a few late fixes, all of these commits have shipped in -next
releases since before the merge window opened, and 0day has given a
build success notification.
The ext4 touches came from Jan, and the xfs touches have Darrick's
reviewed-by. An xfstest for the MAP_SYNC feature has been through
a few round of reviews and is on track to be merged.
- Introduce MAP_SYNC and MAP_SHARED_VALIDATE, a mechanism to enable
'userspace flush' of persistent memory updates via filesystem-dax
mappings. It arranges for any filesystem metadata updates that may
be required to satisfy a write fault to also be flushed ("on disk")
before the kernel returns to userspace from the fault handler.
Effectively every write-fault that dirties metadata completes an
fsync() before returning from the fault handler. The new
MAP_SHARED_VALIDATE mapping type guarantees that the MAP_SYNC flag
is validated as supported by the filesystem's ->mmap() file
operation.
- Add support for the standard ACPI 6.2 label access methods that
replace the NVDIMM_FAMILY_INTEL (vendor specific) label methods.
This enables interoperability with environments that only implement
the standardized methods.
- Add support for the ACPI 6.2 NVDIMM media error injection methods.
- Add support for the NVDIMM_FAMILY_INTEL v1.6 DIMM commands for
latch last shutdown status, firmware update, SMART error injection,
and SMART alarm threshold control.
- Cleanup physical address information disclosures to be root-only.
- Fix revalidation of the DIMM "locked label area" status to support
dynamic unlock of the label area.
- Expand unit test infrastructure to mock the ACPI 6.2 Translate SPA
(system-physical-address) command and error injection commands.
Acknowledgements that came after the commits were pushed to -next:
- 957ac8c421ad ("dax: fix PMD faults on zero-length files"):
Reviewed-by: Ross Zwisler <[email protected]>
- a39e596baa07 ("xfs: support for synchronous DAX faults") and
7b565c9f965b ("xfs: Implement xfs_filemap_pfn_mkwrite() using __xfs_filemap_fault()")
Reviewed-by: Darrick J. Wong <[email protected]>"
* tag 'libnvdimm-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (49 commits)
acpi, nfit: add 'Enable Latch System Shutdown Status' command support
dax: fix general protection fault in dax_alloc_inode
dax: fix PMD faults on zero-length files
dax: stop requiring a live device for dax_flush()
brd: remove dax support
dax: quiet bdev_dax_supported()
fs, dax: unify IOMAP_F_DIRTY read vs write handling policy in the dax core
tools/testing/nvdimm: unit test clear-error commands
acpi, nfit: validate commands against the device type
tools/testing/nvdimm: stricter bounds checking for error injection commands
xfs: support for synchronous DAX faults
xfs: Implement xfs_filemap_pfn_mkwrite() using __xfs_filemap_fault()
ext4: Support for synchronous DAX faults
ext4: Simplify error handling in ext4_dax_huge_fault()
dax: Implement dax_finish_sync_fault()
dax, iomap: Add support for synchronous faults
mm: Define MAP_SYNC and VM_SYNC flags
dax: Allow tuning whether dax_insert_mapping_entry() dirties entry
dax: Allow dax_iomap_fault() to return pfn
dax: Fix comment describing dax_iomap_fault()
...
|
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Pull virtio updates from Michael Tsirkin:
"Fixes in qemu, vhost and virtio"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
fw_cfg: fix the command line module name
vhost/vsock: fix uninitialized vhost_vsock->guest_cid
vhost: fix end of range for access_ok
vhost/scsi: Use safe iteration in vhost_scsi_complete_cmd_work()
virtio_balloon: fix deadlock on OOM
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git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull AFS updates from David Howells:
"kAFS filesystem driver overhaul.
The major points of the overhaul are:
(1) Preliminary groundwork is laid for supporting network-namespacing
of kAFS. The remainder of the namespacing work requires some way
to pass namespace information to submounts triggered by an
automount. This requires something like the mount overhaul that's
in progress.
(2) sockaddr_rxrpc is used in preference to in_addr for holding
addresses internally and add support for talking to the YFS VL
server. With this, kAFS can do everything over IPv6 as well as
IPv4 if it's talking to servers that support it.
(3) Callback handling is overhauled to be generally passive rather
than active. 'Callbacks' are promises by the server to tell us
about data and metadata changes. Callbacks are now checked when
we next touch an inode rather than actively going and looking for
it where possible.
(4) File access permit caching is overhauled to store the caching
information per-inode rather than per-directory, shared over
subordinate files. Whilst older AFS servers only allow ACLs on
directories (shared to the files in that directory), newer AFS
servers break that restriction.
To improve memory usage and to make it easier to do mass-key
removal, permit combinations are cached and shared.
(5) Cell database management is overhauled to allow lighter locks to
be used and to make cell records autonomous state machines that
look after getting their own DNS records and cleaning themselves
up, in particular preventing races in acquiring and relinquishing
the fscache token for the cell.
(6) Volume caching is overhauled. The afs_vlocation record is got rid
of to simplify things and the superblock is now keyed on the cell
and the numeric volume ID only. The volume record is tied to a
superblock and normal superblock management is used to mediate
the lifetime of the volume fscache token.
(7) File server record caching is overhauled to make server records
independent of cells and volumes. A server can be in multiple
cells (in such a case, the administrator must make sure that the
VL services for all cells correctly reflect the volumes shared
between those cells).
Server records are now indexed using the UUID of the server
rather than the address since a server can have multiple
addresses.
(8) File server rotation is overhauled to handle VMOVED, VBUSY (and
similar), VOFFLINE and VNOVOL indications and to handle rotation
both of servers and addresses of those servers. The rotation will
also wait and retry if the server says it is busy.
(9) Data writeback is overhauled. Each inode no longer stores a list
of modified sections tagged with the key that authorised it in
favour of noting the modified region of a page in page->private
and storing a list of keys that made modifications in the inode.
This simplifies things and allows other keys to be used to
actually write to the server if a key that made a modification
becomes useless.
(10) Writable mmap() is implemented. This allows a kernel to be build
entirely on AFS.
Note that Pre AFS-3.4 servers are no longer supported, though this can
be added back if necessary (AFS-3.4 was released in 1998)"
* tag 'afs-next-20171113' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (35 commits)
afs: Protect call->state changes against signals
afs: Trace page dirty/clean
afs: Implement shared-writeable mmap
afs: Get rid of the afs_writeback record
afs: Introduce a file-private data record
afs: Use a dynamic port if 7001 is in use
afs: Fix directory read/modify race
afs: Trace the sending of pages
afs: Trace the initiation and completion of client calls
afs: Fix documentation on # vs % prefix in mount source specification
afs: Fix total-length calculation for multiple-page send
afs: Only progress call state at end of Tx phase from rxrpc callback
afs: Make use of the YFS service upgrade to fully support IPv6
afs: Overhaul volume and server record caching and fileserver rotation
afs: Move server rotation code into its own file
afs: Add an address list concept
afs: Overhaul cell database management
afs: Overhaul permit caching
afs: Overhaul the callback handling
afs: Rename struct afs_call server member to cm_server
...
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Pull drm updates from Dave Airlie:
"This is the main drm pull request for v4.15.
Core:
- Atomic object lifetime fixes
- Atomic iterator improvements
- Sparse/smatch fixes
- Legacy kms ioctls to be interruptible
- EDID override improvements
- fb/gem helper cleanups
- Simple outreachy patches
- Documentation improvements
- Fix dma-buf rcu races
- DRM mode object leasing for improving VR use cases.
- vgaarb improvements for non-x86 platforms.
New driver:
- tve200: Faraday Technology TVE200 block.
This "TV Encoder" encodes a ITU-T BT.656 stream and can be found in
the StorLink SL3516 (later Cortina Systems CS3516) as well as the
Grain Media GM8180.
New bridges:
- SiI9234 support
New panels:
- S6E63J0X03, OTM8009A, Seiko 43WVF1G, 7" rpi touch panel, Toshiba
LT089AC19000, Innolux AT043TN24
i915:
- Remove Coffeelake from alpha support
- Cannonlake workarounds
- Infoframe refactoring for DisplayPort
- VBT updates
- DisplayPort vswing/emph/buffer translation refactoring
- CCS fixes
- Restore GPU clock boost on missed vblanks
- Scatter list updates for userptr allocations
- Gen9+ transition watermarks
- Display IPC (Isochronous Priority Control)
- Private PAT management
- GVT: improved error handling and pci config sanitizing
- Execlist refactoring
- Transparent Huge Page support
- User defined priorities support
- HuC/GuC firmware refactoring
- DP MST fixes
- eDP power sequencing fixes
- Use RCU instead of stop_machine
- PSR state tracking support
- Eviction fixes
- BDW DP aux channel timeout fixes
- LSPCON fixes
- Cannonlake PLL fixes
amdgpu:
- Per VM BO support
- Powerplay cleanups
- CI powerplay support
- PASID mgr for kfd
- SR-IOV fixes
- initial GPU reset for vega10
- Prime mmap support
- TTM updates
- Clock query interface for Raven
- Fence to handle ioctl
- UVD encode ring support on Polaris
- Transparent huge page DMA support
- Compute LRU pipe tweaks
- BO flag to allow buffers to opt out of implicit sync
- CTX priority setting API
- VRAM lost infrastructure plumbing
qxl:
- fix flicker since atomic rework
amdkfd:
- Further improvements from internal AMD tree
- Usermode events
- Drop radeon support
nouveau:
- Pascal temperature sensor support
- Improved BAR2 handling
- MMU rework to support Pascal MMU
exynos:
- Improved HDMI/mixer support
- HDMI audio interface support
tegra:
- Prep work for tegra186
- Cleanup/fixes
msm:
- Preemption support for a5xx
- Display fixes for 8x96 (snapdragon 820)
- Async cursor plane fixes
- FW loading rework
- GPU debugging improvements
vc4:
- Prep for DSI panels
- fix T-format tiling scanout
- New madvise ioctl
Rockchip:
- LVDS support
omapdrm:
- omap4 HDMI CEC support
etnaviv:
- GPU performance counters groundwork
sun4i:
- refactor driver load + TCON backend
- HDMI improvements
- A31 support
- Misc fixes
udl:
- Probe/EDID read fixes.
tilcdc:
- Misc fixes.
pl111:
- Support more variants
adv7511:
- Improve EDID handling.
- HDMI CEC support
sii8620:
- Add remote control support"
* tag 'drm-for-v4.15' of git://people.freedesktop.org/~airlied/linux: (1480 commits)
drm/rockchip: analogix_dp: Use mutex rather than spinlock
drm/mode_object: fix documentation for object lookups.
drm/i915: Reorder context-close to avoid calling i915_vma_close() under RCU
drm/i915: Move init_clock_gating() back to where it was
drm/i915: Prune the reservation shared fence array
drm/i915: Idle the GPU before shinking everything
drm/i915: Lock llist_del_first() vs llist_del_all()
drm/i915: Calculate ironlake intermediate watermarks correctly, v2.
drm/i915: Disable lazy PPGTT page table optimization for vGPU
drm/i915/execlists: Remove the priority "optimisation"
drm/i915: Filter out spurious execlists context-switch interrupts
drm/amdgpu: use irq-safe lock for kiq->ring_lock
drm/amdgpu: bypass lru touch for KIQ ring submission
drm/amdgpu: Potential uninitialized variable in amdgpu_vm_update_directories()
drm/amdgpu: potential uninitialized variable in amdgpu_vce_ring_parse_cs()
drm/amd/powerplay: initialize a variable before using it
drm/amd/powerplay: suppress KASAN out of bounds warning in vega10_populate_all_memory_levels
drm/amd/amdgpu: fix evicted VRAM bo adjudgement condition
drm/vblank: Tune drm_crtc_accurate_vblank_count() WARN down to a debug
drm/rockchip: add CONFIG_OF dependency for lvds
...
|
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Merge updates from Andrew Morton:
- a few misc bits
- ocfs2 updates
- almost all of MM
* emailed patches from Andrew Morton <[email protected]>: (131 commits)
memory hotplug: fix comments when adding section
mm: make alloc_node_mem_map a void call if we don't have CONFIG_FLAT_NODE_MEM_MAP
mm: simplify nodemask printing
mm,oom_reaper: remove pointless kthread_run() error check
mm/page_ext.c: check if page_ext is not prepared
writeback: remove unused function parameter
mm: do not rely on preempt_count in print_vma_addr
mm, sparse: do not swamp log with huge vmemmap allocation failures
mm/hmm: remove redundant variable align_end
mm/list_lru.c: mark expected switch fall-through
mm/shmem.c: mark expected switch fall-through
mm/page_alloc.c: broken deferred calculation
mm: don't warn about allocations which stall for too long
fs: fuse: account fuse_inode slab memory as reclaimable
mm, page_alloc: fix potential false positive in __zone_watermark_ok
mm: mlock: remove lru_add_drain_all()
mm, sysctl: make NUMA stats configurable
shmem: convert shmem_init_inodecache() to void
Unify migrate_pages and move_pages access checks
mm, pagevec: rename pagevec drained field
...
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Here, pfn_to_node should be page_to_nid.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Fan Du <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
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CONFIG_FLAT_NODE_MEM_MAP
free_area_init_node() calls alloc_node_mem_map(), but this function does
nothing unless we have CONFIG_FLAT_NODE_MEM_MAP.
As a cleanup, we can move the "#ifdef CONFIG_FLAT_NODE_MEM_MAP" within
alloc_node_mem_map() out of the function, and define a
alloc_node_mem_map() { } when CONFIG_FLAT_NODE_MEM_MAP is not present.
This also moves the printk that lays within the "#ifdef
CONFIG_FLAT_NODE_MEM_MAP" block from free_area_init_node() to
alloc_node_mem_map(), getting rid of the "#ifdef
CONFIG_FLAT_NODE_MEM_MAP" in free_area_init_node().
[[email protected]: clean up the printk while we're there]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Oscar Salvador <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
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alloc_warn() and dump_header() have to explicitly handle NULL nodemask
which forces both paths to use pr_cont. We can do better. printk
already handles NULL pointers properly so all we need is to teach
nodemask_pr_args to handle NULL nodemask carefully. This allows
simplification of both alloc_warn() and dump_header() and gets rid of
pr_cont altogether.
This patch has been motivated by patch from Joe Perches
http://lkml.kernel.org/r/b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@perches.com
[[email protected]: fix tile warning, per Arnd]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michal Hocko <[email protected]>
Acked-by: Joe Perches <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
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Since oom_init() is called before userspace processes start, memory
allocation failure for creating the OOM reaper kernel thread will let
the OOM killer call panic() rather than wake up the OOM reaper.
Link: http://lkml.kernel.org/r/1510137800-4602-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
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online_page_ext() and page_ext_init() allocate page_ext for each
section, but they do not allocate if the first PFN is !pfn_present(pfn)
or !pfn_valid(pfn). Then section->page_ext remains as NULL.
lookup_page_ext checks NULL only if CONFIG_DEBUG_VM is enabled. For a
valid PFN, __set_page_owner will try to get page_ext through
lookup_page_ext. Without CONFIG_DEBUG_VM lookup_page_ext will misuse
NULL pointer as value 0. This incurrs invalid address access.
This is the panic example when PFN 0x100000 is not valid but PFN
0x13FC00 is being used for page_ext. section->page_ext is NULL,
get_entry returned invalid page_ext address as 0x1DFA000 for a PFN
0x13FC00.
To avoid this panic, CONFIG_DEBUG_VM should be removed so that page_ext
will be checked at all times.
Unable to handle kernel paging request at virtual address 01dfa014
------------[ cut here ]------------
Kernel BUG at ffffff80082371e0 [verbose debug info unavailable]
Internal error: Oops: 96000045 [#1] PREEMPT SMP
Modules linked in:
PC is at __set_page_owner+0x48/0x78
LR is at __set_page_owner+0x44/0x78
__set_page_owner+0x48/0x78
get_page_from_freelist+0x880/0x8e8
__alloc_pages_nodemask+0x14c/0xc48
__do_page_cache_readahead+0xdc/0x264
filemap_fault+0x2ac/0x550
ext4_filemap_fault+0x3c/0x58
__do_fault+0x80/0x120
handle_mm_fault+0x704/0xbb0
do_page_fault+0x2e8/0x394
do_mem_abort+0x88/0x124
Pre-4.7 kernels also need commit f86e4271978b ("mm: check the return
value of lookup_page_ext for all call sites").
Link: http://lkml.kernel.org/r/[email protected]
Fixes: eefa864b701d ("mm/page_ext: resurrect struct page extending code for debugging")
Signed-off-by: Jaewon Kim <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: <[email protected]> [depends on f86e427197, see above]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
The parameter `struct bdi_writeback *wb` is not been used in the
function body. Remove it.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Wang Long <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Jens Axboe <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
The preempt count check on print_vma_addr has been added by commit
e8bff74afbdb ("x86: fix "BUG: sleeping function called from invalid
context" in print_vma_addr()") and it relied on the elevated preempt
count from preempt_conditional_sti because preempt_count check doesn't
work on non preemptive kernels by default.
The code has evolved though and commit d99e1bd175f4 ("x86/entry/traps:
Refactor preemption and interrupt flag handling") has replaced
preempt_conditional_sti by an explicit preempt_disable which is noop on
!PREEMPT so the check in print_vma_addr is broken.
Fix the issue by using trylock on mmap_sem rather than chacking the
preempt count. The allocation we are relying on has to be GFP_NOWAIT as
well. There is a chance that we won't dump the vma state if the lock is
contended or the memory short but this is acceptable outcome and much
less fragile than the not working preemption check or tricks around it.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: d99e1bd175f4 ("x86/entry/traps: Refactor preemption and interrupt flag handling")
Signed-off-by: Michal Hocko <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Yang Shi <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
While doing memory hotplug tests under heavy memory pressure we have
noticed too many page allocation failures when allocating vmemmap memmap
backed by huge page
kworker/u3072:1: page allocation failure: order:9, mode:0x24084c0(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO)
[...]
Call Trace:
dump_trace+0x59/0x310
show_stack_log_lvl+0xea/0x170
show_stack+0x21/0x40
dump_stack+0x5c/0x7c
warn_alloc_failed+0xe2/0x150
__alloc_pages_nodemask+0x3ed/0xb20
alloc_pages_current+0x7f/0x100
vmemmap_alloc_block+0x79/0xb6
__vmemmap_alloc_block_buf+0x136/0x145
vmemmap_populate+0xd2/0x2b9
sparse_mem_map_populate+0x23/0x30
sparse_add_one_section+0x68/0x18e
__add_pages+0x10a/0x1d0
arch_add_memory+0x4a/0xc0
add_memory_resource+0x89/0x160
add_memory+0x6d/0xd0
acpi_memory_device_add+0x181/0x251
acpi_bus_attach+0xfd/0x19b
acpi_bus_scan+0x59/0x69
acpi_device_hotplug+0xd2/0x41f
acpi_hotplug_work_fn+0x1a/0x23
process_one_work+0x14e/0x410
worker_thread+0x116/0x490
kthread+0xbd/0xe0
ret_from_fork+0x3f/0x70
and we do see many of those because essentially every allocation fails
for each memory section. This is an excessive way to tell the user that
there is nothing to really worry about because we do have a fallback
mechanism to use base pages. The only downside might be a performance
degradation due to TLB pressure.
This patch changes vmemmap_alloc_block() to use __GFP_NOWARN and warn
explicitly once on the first allocation failure. This will reduce the
noise in the kernel log considerably, while we still have an indication
that a performance might be impacted.
[[email protected]: forgot to git add the follow up fix]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Signed-off-by: Michal Hocko <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Khalid Aziz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Variable align_end is assigned a value but it is never read, so the
variable is redundant and can be removed. Cleans up the clang warning:
Value stored to 'align_end' is never read
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Colin Ian King <[email protected]>
Reviewed-by: Jérôme Glisse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In preparation for enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In reset_deferred_meminit() we determine number of pages that must not
be deferred. We initialize pages for at least 2G of memory, but also
pages for reserved memory in this node.
The reserved memory is determined in this function:
memblock_reserved_memory_within(), which operates over physical
addresses, and returns size in bytes. However, reset_deferred_meminit()
assumes that that this function operates with pfns, and returns page
count.
The result is that in the best case machine boots slower than expected
due to initializing more pages than needed in single thread, and in the
worst case panics because fewer than needed pages are initialized early.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 864b9a393dcb ("mm: consider memblock reservations for deferred memory initialization sizing")
Signed-off-by: Pavel Tatashin <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit 63f53dea0c98 ("mm: warn about allocations which stall for too
long") was a great step for reducing possibility of silent hang up
problem caused by memory allocation stalls. But this commit reverts it,
for it is possible to trigger OOM lockup and/or soft lockups when many
threads concurrently called warn_alloc() (in order to warn about memory
allocation stalls) due to current implementation of printk(), and it is
difficult to obtain useful information due to limitation of synchronous
warning approach.
Current printk() implementation flushes all pending logs using the
context of a thread which called console_unlock(). printk() should be
able to flush all pending logs eventually unless somebody continues
appending to printk() buffer.
Since warn_alloc() started appending to printk() buffer while waiting
for oom_kill_process() to make forward progress when oom_kill_process()
is processing pending logs, it became possible for warn_alloc() to force
oom_kill_process() loop inside printk(). As a result, warn_alloc()
significantly increased possibility of preventing oom_kill_process()
from making forward progress.
---------- Pseudo code start ----------
Before warn_alloc() was introduced:
retry:
if (mutex_trylock(&oom_lock)) {
while (atomic_read(&printk_pending_logs) > 0) {
atomic_dec(&printk_pending_logs);
print_one_log();
}
// Send SIGKILL here.
mutex_unlock(&oom_lock)
}
goto retry;
After warn_alloc() was introduced:
retry:
if (mutex_trylock(&oom_lock)) {
while (atomic_read(&printk_pending_logs) > 0) {
atomic_dec(&printk_pending_logs);
print_one_log();
}
// Send SIGKILL here.
mutex_unlock(&oom_lock)
} else if (waited_for_10seconds()) {
atomic_inc(&printk_pending_logs);
}
goto retry;
---------- Pseudo code end ----------
Although waited_for_10seconds() becomes true once per 10 seconds,
unbounded number of threads can call waited_for_10seconds() at the same
time. Also, since threads doing waited_for_10seconds() keep doing
almost busy loop, the thread doing print_one_log() can use little CPU
resource. Therefore, this situation can be simplified like
---------- Pseudo code start ----------
retry:
if (mutex_trylock(&oom_lock)) {
while (atomic_read(&printk_pending_logs) > 0) {
atomic_dec(&printk_pending_logs);
print_one_log();
}
// Send SIGKILL here.
mutex_unlock(&oom_lock)
} else {
atomic_inc(&printk_pending_logs);
}
goto retry;
---------- Pseudo code end ----------
when printk() is called faster than print_one_log() can process a log.
One of possible mitigation would be to introduce a new lock in order to
make sure that no other series of printk() (either oom_kill_process() or
warn_alloc()) can append to printk() buffer when one series of printk()
(either oom_kill_process() or warn_alloc()) is already in progress.
Such serialization will also help obtaining kernel messages in readable
form.
---------- Pseudo code start ----------
retry:
if (mutex_trylock(&oom_lock)) {
mutex_lock(&oom_printk_lock);
while (atomic_read(&printk_pending_logs) > 0) {
atomic_dec(&printk_pending_logs);
print_one_log();
}
// Send SIGKILL here.
mutex_unlock(&oom_printk_lock);
mutex_unlock(&oom_lock)
} else {
if (mutex_trylock(&oom_printk_lock)) {
atomic_inc(&printk_pending_logs);
mutex_unlock(&oom_printk_lock);
}
}
goto retry;
---------- Pseudo code end ----------
But this commit does not go that direction, for we don't want to
introduce a new lock dependency, and we unlikely be able to obtain
useful information even if we serialized oom_kill_process() and
warn_alloc().
Synchronous approach is prone to unexpected results (e.g. too late [1],
too frequent [2], overlooked [3]). As far as I know, warn_alloc() never
helped with providing information other than "something is going wrong".
I want to consider asynchronous approach which can obtain information
during stalls with possibly relevant threads (e.g. the owner of
oom_lock and kswapd-like threads) and serve as a trigger for actions
(e.g. turn on/off tracepoints, ask libvirt daemon to take a memory dump
of stalling KVM guest for diagnostic purpose).
This commit temporarily loses ability to report e.g. OOM lockup due to
unable to invoke the OOM killer due to !__GFP_FS allocation request.
But asynchronous approach will be able to detect such situation and emit
warning. Thus, let's remove warn_alloc().
[1] https://bugzilla.kernel.org/show_bug.cgi?id=192981
[2] http://lkml.kernel.org/r/CAM_iQpWuPVGc2ky8M-9yukECtS+zKjiDasNymX7rMcBjBFyM_A@mail.gmail.com
[3] commit db73ee0d46379922 ("mm, vmscan: do not loop on too_many_isolated for ever"))
Link: http://lkml.kernel.org/r/1509017339-4802-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <[email protected]>
Reported-by: Cong Wang <[email protected]>
Reported-by: yuwang.yuwang <[email protected]>
Reported-by: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
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Since commit 97a16fc82a7c ("mm, page_alloc: only enforce watermarks for
order-0 allocations"), __zone_watermark_ok() check for high-order
allocations will shortcut per-migratetype free list checks for
ALLOC_HARDER allocations, and return true as long as there's free page
of any migratetype. The intention is that ALLOC_HARDER can allocate
from MIGRATE_HIGHATOMIC free lists, while normal allocations can't.
However, as a side effect, the watermark check will then also return
true when there are pages only on the MIGRATE_ISOLATE list, or (prior to
CMA conversion to ZONE_MOVABLE) on the MIGRATE_CMA list. Since the
allocation cannot actually obtain isolated pages, and might not be able
to obtain CMA pages, this can result in a false positive.
The condition should be rare and perhaps the outcome is not a fatal one.
Still, it's better if the watermark check is correct. There also
shouldn't be a performance tradeoff here.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 97a16fc82a7c ("mm, page_alloc: only enforce watermarks for order-0 allocations")
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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