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The code for gso_max_size was added originally to allow for debugging and
workaround of buggy devices that couldn't support TSO with blocks 64K in
size. The original reason for limiting it to 64K was because that was the
existing limits of IPv4 and non-jumbogram IPv6 length fields.
With the addition of Big TCP we can remove this limit and allow the value
to potentially go up to UINT_MAX and instead be limited by the tso_max_size
value.
So in order to support this we need to go through and clean up the
remaining users of the gso_max_size value so that the values will cap at
64K for non-TCPv6 flows. In addition we can clean up the GSO_MAX_SIZE value
so that 64K becomes GSO_LEGACY_MAX_SIZE and UINT_MAX will now be the upper
limit for GSO_MAX_SIZE.
v6: (edumazet) fixed a compile error if CONFIG_IPV6=n,
in a new sk_trim_gso_size() helper.
netif_set_tso_max_size() caps the requested TSO size
with GSO_MAX_SIZE.
Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Log a few more path related status codes.
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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This was only used by the ide-cd driver, which went away in
commit b7fb14d3ac63 ("ide: remove the legacy ide driver")
so we might as well take advantage of that and get rid of
this hook as well.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: https://lore.kernel.org/all/20220427132436.12795-2-paul.gortmaker@windriver.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220515205833.944139-3-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently we have 3 primitives for removing an opened file from descriptor
table - pick_file(), __close_fd_get_file() and close_fd_get_file(). Their
calling conventions are rather odd and there's a code duplication for no
good reason. They can be unified -
1) have __range_close() cap max_fd in the very beginning; that way
we don't need separate way for pick_file() to report being past the end
of descriptor table.
2) make {__,}close_fd_get_file() return file (or NULL) directly, rather
than returning it via struct file ** argument. Don't bother with
(bogus) return value - nobody wants that -ENOENT.
3) make pick_file() return NULL on unopened descriptor - the only caller
that used to care about the distinction between descriptor past the end
of descriptor table and finding NULL in descriptor table doesn't give
a damn after (1).
4) lift ->files_lock out of pick_file()
That actually simplifies the callers, as well as the primitives themselves.
Code duplication is also gone...
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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These two interface were added in 091141a42 commit,
but now there is no place to call them.
The only user of fput/fget_many() was removed in commit
62906e89e63b ("io_uring: remove file batch-get optimisation").
A user of get_file_rcu_many() were removed in commit
f073531070d2 ("init: add an init_dup helper").
And replace atomic_long_sub/add to atomic_long_dec/inc
can improve performance.
Here are the test results of unixbench:
Cmd: ./Run -c 64 context1
Without patch:
System Benchmarks Partial Index BASELINE RESULT INDEX
Pipe-based Context Switching 4000.0 2798407.0 6996.0
========
System Benchmarks Index Score (Partial Only) 6996.0
With patch:
System Benchmarks Partial Index BASELINE RESULT INDEX
Pipe-based Context Switching 4000.0 3486268.8 8715.7
========
System Benchmarks Index Score (Partial Only) 8715.7
Signed-off-by: Gou Hao <gouhao@uniontech.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Fix the warning - "Enum value 'NR_DAMON_OPS' not described in enum
'damon_ops_id'" generated by the command "make pdfdocs"
Link: https://lkml.kernel.org/r/20220508073316.141401-1-gautammenghani201@gmail.com
Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We must add hugetlb_free_vmemmap=on (or "off") to the boot cmdline and
reboot the server to enable or disable the feature of optimizing vmemmap
pages associated with HugeTLB pages. However, rebooting usually takes a
long time. So add a sysctl to enable or disable the feature at runtime
without rebooting. Why we need this? There are 3 use cases.
1) The feature of minimizing overhead of struct page associated with
each HugeTLB is disabled by default without passing
"hugetlb_free_vmemmap=on" to the boot cmdline. When we (ByteDance)
deliver the servers to the users who want to enable this feature, they
have to configure the grub (change boot cmdline) and reboot the
servers, whereas rebooting usually takes a long time (we have thousands
of servers). It's a very bad experience for the users. So we need a
approach to enable this feature after rebooting. This is a use case in
our practical environment.
2) Some use cases are that HugeTLB pages are allocated 'on the fly'
instead of being pulled from the HugeTLB pool, those workloads would be
affected with this feature enabled. Those workloads could be
identified by the characteristics of they never explicitly allocating
huge pages with 'nr_hugepages' but only set 'nr_overcommit_hugepages'
and then let the pages be allocated from the buddy allocator at fault
time. We can confirm it is a real use case from the commit
099730d67417. For those workloads, the page fault time could be ~2x
slower than before. We suspect those users want to disable this
feature if the system has enabled this before and they don't think the
memory savings benefit is enough to make up for the performance drop.
3) If the workload which wants vmemmap pages to be optimized and the
workload which wants to set 'nr_overcommit_hugepages' and does not want
the extera overhead at fault time when the overcommitted pages be
allocated from the buddy allocator are deployed in the same server.
The user could enable this feature and set 'nr_hugepages' and
'nr_overcommit_hugepages', then disable the feature. In this case, the
overcommited HugeTLB pages will not encounter the extra overhead at
fault time.
Link: https://lkml.kernel.org/r/20220512041142.39501-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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On some architectures (like ARM64), it can support CONT-PTE/PMD size
hugetlb, which means it can support not only PMD/PUD size hugetlb: 2M and
1G, but also CONT-PTE/PMD size: 64K and 32M if a 4K page size specified.
When migrating a hugetlb page, we will get the relevant page table entry
by huge_pte_offset() only once to nuke it and remap it with a migration
pte entry. This is correct for PMD or PUD size hugetlb, since they always
contain only one pmd entry or pud entry in the page table.
However this is incorrect for CONT-PTE and CONT-PMD size hugetlb, since
they can contain several continuous pte or pmd entry with same page table
attributes. So we will nuke or remap only one pte or pmd entry for this
CONT-PTE/PMD size hugetlb page, which is not expected for hugetlb
migration. The problem is we can still continue to modify the subpages'
data of a hugetlb page during migrating a hugetlb page, which can cause a
serious data consistent issue, since we did not nuke the page table entry
and set a migration pte for the subpages of a hugetlb page.
To fix this issue, we should change to use huge_ptep_clear_flush() to nuke
a hugetlb page table, and remap it with set_huge_pte_at() and
set_huge_swap_pte_at() when migrating a hugetlb page, which already
considered the CONT-PTE or CONT-PMD size hugetlb.
[akpm@linux-foundation.org: fix nommu build]
[baolin.wang@linux.alibaba.com: fix build errors for !CONFIG_MMU]
Link: https://lkml.kernel.org/r/a4baca670aca637e7198d9ae4543b8873cb224dc.1652270205.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/ea5abf529f0997b5430961012bfda6166c1efc8c.1652147571.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The use of kmap_atomic() is new code is being deprecated in favor of
kmap_local_page(). For this reason the "Using kmap_atomic" section in
highmem.rst is obsolete and unnecessary, but it can still help developers
if it were moved to kdocs in highmem.h.
Therefore, move the relevant parts of this section from highmem.rst and
merge them with the kdocs in highmem.h.
Link: https://lkml.kernel.org/r/20220428212455.892-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Extend and reorganize Highmem's documentation", v4.
This series has the purpose to extend and reorganize Highmem's
documentation.
This is a work in progress because some information should still be moved
from highmem.rst to highmem.h and highmem-internal.h. Specifically I'm
talking about moving the "how to" information to the relevant headers, as
it as been suggested by Ira Weiny (Intel).
Also, this is a work in progress because some kdocs in highmem.h and
highmem-internal.h should be improved.
This patch (of 4):
`scripts/kernel-doc -v -none include/linux/highmem*` reports the following
warnings:
include/linux/highmem.h:160: warning: expecting prototype for kunmap_atomic(). Prototype was for nr_free_highpages() instead
include/linux/highmem.h:204: warning: No description found for return value of 'alloc_zeroed_user_highpage_movable'
include/linux/highmem-internal.h:256: warning: Function parameter or member '__addr' not described in 'kunmap_atomic'
include/linux/highmem-internal.h:256: warning: Excess function parameter 'addr' description in 'kunmap_atomic'
Fix these warnings by (1) moving the kernel-doc comments from highmem.h to
highmem-internal.h (which is the file were the kunmap_atomic() macro is
actually defined), (2) extending and merging it with the comment which was
already in highmem-internal.h, and (3) using correct parameter names (4)
correcting a few technical inaccuracies in comments, and (5) adding a
deprecation notice in kunmap_atomic() for consistency with kmap_atomic().
Link: https://lkml.kernel.org/r/20220428212455.892-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220428212455.892-2-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Instead of having uninitialized versions of arguments as separate
bpf_arg_types (eg ARG_PTR_TO_UNINIT_MEM as the uninitialized version
of ARG_PTR_TO_MEM), we can instead use MEM_UNINIT as a bpf_type_flag
modifier to denote that the argument is uninitialized.
Doing so cleans up some of the logic in the verifier. We no longer
need to do two checks against an argument type (eg "if
(base_type(arg_type) == ARG_PTR_TO_MEM || base_type(arg_type) ==
ARG_PTR_TO_UNINIT_MEM)"), since uninitialized and initialized
versions of the same argument type will now share the same base type.
In the near future, MEM_UNINIT will be used by dynptr helper functions
as well.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220509224257.3222614-2-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The addition of random_get_entropy_fallback() provides access to
whichever time source has the highest frequency, which is useful for
gathering entropy on platforms without available cycle counters. It's
not necessarily as good as being able to quickly access a cycle counter
that the CPU has, but it's still something, even when it falls back to
being jiffies-based.
In the event that a given arch does not define get_cycles(), falling
back to the get_cycles() default implementation that returns 0 is really
not the best we can do. Instead, at least calling
random_get_entropy_fallback() would be preferable, because that always
needs to return _something_, even falling back to jiffies eventually.
It's not as though random_get_entropy_fallback() is super high precision
or guaranteed to be entropic, but basically anything that's not zero all
the time is better than returning zero all the time.
Finally, since random_get_entropy_fallback() is used during extremely
early boot when randomizing freelists in mm_init(), it can be called
before timekeeping has been initialized. In that case there really is
nothing we can do; jiffies hasn't even started ticking yet. So just give
up and return 0.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Theodore Ts'o <tytso@mit.edu>
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The struct security_hook_list member lsm is assigned in
security_add_hooks() with string literals passed from the individual
security modules. Declare the function parameter and the struct member
const to signal their immutability.
Reported by Clang [-Wwrite-strings]:
security/selinux/hooks.c:7388:63: error: passing 'const char [8]'
to parameter of type 'char *' discards qualifiers
[-Werror,-Wincompatible-pointer-types-discards-qualifiers]
security_add_hooks(selinux_hooks,
ARRAY_SIZE(selinux_hooks), selinux);
^~~~~~~~~
./include/linux/lsm_hooks.h:1629:11: note: passing argument to
parameter 'lsm' here
char *lsm);
^
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Pull NFS client bugfixes from Trond Myklebust:
"One more pull request. There was a bug in the fix to ensure that gss-
proxy continues to work correctly after we fixed the AF_LOCAL socket
leak in the RPC code. This therefore reverts that broken patch, and
replaces it with one that works correctly.
Stable fixes:
- SUNRPC: Ensure that the gssproxy client can start in a connected
state
Bugfixes:
- Revert "SUNRPC: Ensure gss-proxy connects on setup"
- nfs: fix broken handling of the softreval mount option"
* tag 'nfs-for-5.18-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
nfs: fix broken handling of the softreval mount option
SUNRPC: Ensure that the gssproxy client can start in a connected state
Revert "SUNRPC: Ensure gss-proxy connects on setup"
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VFIO PCI does a security check as part of hot reset to prove that the user
has permission to manipulate all the devices that will be impacted by the
reset.
Use a new API vfio_file_has_dev() to perform this security check against
the struct file directly and remove the vfio_group from VFIO PCI.
Since VFIO PCI was the last user of vfio_group_get_external_user() and
vfio_group_put_external_user() remove it as well.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/8-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Just change the argument from struct vfio_group to struct file *.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Instead of a general extension check change the function into a limited
test if the iommu_domain has enforced coherency, which is the only thing
kvm needs to query.
Make the new op self contained by properly refcounting the container
before touching it.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/5-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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vfio_group_fops_open() ensures there is only ever one struct file open for
any struct vfio_group at any time:
/* Do we need multiple instances of the group open? Seems not. */
opened = atomic_cmpxchg(&group->opened, 0, 1);
if (opened) {
vfio_group_put(group);
return -EBUSY;
Therefor the struct file * can be used directly to search the list of VFIO
groups that KVM keeps instead of using the
vfio_external_group_match_file() callback to try to figure out if the
passed in FD matches the list or not.
Delete vfio_external_group_match_file().
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/4-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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The only caller wants to get a pointer to the struct iommu_group
associated with the VFIO group file. Instead of returning the group ID
then searching sysfs for that string to get the struct iommu_group just
directly return the iommu_group pointer already held by the vfio_group
struct.
It already has a safe lifetime due to the struct file kref, the vfio_group
and thus the iommu_group cannot be destroyed while the group file is open.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Merge IOMMU dependencies for vfio.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Fixes the following sparse warnings:
include/trace/events/*: sparse: cast to restricted gfp_t
include/trace/events/*: sparse: restricted gfp_t degrades to integer
gfp_t type is bitwise and requires __force attributes for any casts.
Link: https://lkml.kernel.org/r/331d88fe-f4f7-657c-02a2-d977f15fbff6@openvz.org
Signed-off-by: Vasily Averin <vvs@openvz.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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p4d_clear_huge may be optimized for void return type and function usage.
vunmap_p4d_range function saves a few steps here.
Link: https://lkml.kernel.org/r/20220507150630.90399-1-kunyu@nfschina.com
Signed-off-by: Li kunyu <kunyu@nfschina.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, there is no architecture definition __HAVE_ARCH_PTEP_CLEAR,
Generic ptep_clear() is the only definition for all architecture, So drop
the "#ifndef __HAVE_ARCH_PTEP_CLEAR".
Link: https://lkml.kernel.org/r/20220507110114.4128854-5-tongtiangen@huawei.com
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Move ptep_clear() to the include/linux/pgtable.h and add page table check
relate hooks to some helpers, it's prepare for support page table check
feature on new architecture.
Optimize the implementation of ptep_clear(), page table hooks added page
table check stubs, the interface control should be at stubs, there is no
rationale for doing a IS_ENABLED() check here.
For architectures that do not enable CONFIG_PAGE_TABLE_CHECK, they will
call a fallback page table check stubs[1] when getting their page table
helpers[2] in include/linux/pgtable.h.
[1] page table check stubs defined in include/linux/page_table_check.h
[2] ptep_clear() ptep_get_and_clear() pmdp_huge_get_and_clear()
pudp_huge_get_and_clear()
Link: https://lkml.kernel.org/r/20220507110114.4128854-4-tongtiangen@huawei.com
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This is the folio equivalent of PageMovable() which is needed to
convert mm/migrate.c to folios.
Link: https://lkml.kernel.org/r/20220504182857.4013401-26-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This is the equivalent of PageMappingFlags and is needed for converting
mm/migrate.c to folios.
Link: https://lkml.kernel.org/r/20220504182857.4013401-25-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
shmem_swapin_page() only brings in order-0 pages, which are folios
by definition.
Link: https://lkml.kernel.org/r/20220504182857.4013401-24-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The only use of the page argument to cgroup_throttle_swaprate() is to get
the node ID, and this will be the same for all pages in the folio, so just
pass in the first page of the folio.
Link: https://lkml.kernel.org/r/20220504182857.4013401-18-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The call to can_split_folio() in vmscan is currently guarded by a test of
PageTransHuge() so the BUILD_BUG() is eliminated if THP are disabled. The
next patch replaces that test with folio_test_large() which may be true,
even when THP are disabled. However, if THP are disabled, we cannot
split, so an unconditional return of false is appropriate.
Link: https://lkml.kernel.org/r/20220504182857.4013401-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove a hidden call to compound_head(), and account nr_pages instead of a
single page. This matches the code in lru_lazyfree_fn() that accounts
nr_pages to PGLAZYFREE.
Link: https://lkml.kernel.org/r/20220504182857.4013401-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This removes an assumption that a large folio is HPAGE_PMD_NR pages
in size.
Link: https://lkml.kernel.org/r/20220504182857.4013401-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers have now been converted to use vma_alloc_folio(), so convert
the body of alloc_pages_vma() to allocate folios instead.
Link: https://lkml.kernel.org/r/20220504182857.4013401-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now alloc_contig_range() works at pageblock granularity. Change CMA
allocation, which uses alloc_contig_range(), to use pageblock_nr_pages
alignment.
Link: https://lkml.kernel.org/r/20220425143118.2850746-6-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Ren <renzhengeek@gmail.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
alloc_contig_range() worked at MAX_ORDER_NR_PAGES granularity to avoid
merging pageblocks with different migratetypes. It might unnecessarily
convert extra pageblocks at the beginning and at the end of the range.
Change alloc_contig_range() to work at pageblock granularity.
Special handling is needed for free pages and in-use pages across the
boundaries of the range specified by alloc_contig_range(). Because these=
Partially isolated pages causes free page accounting issues. The free
pages will be split and freed into separate migratetype lists; the in-use=
Pages will be migrated then the freed pages will be handled in the
aforementioned way.
[ziy@nvidia.com: fix deadlock/crash]
Link: https://lkml.kernel.org/r/23A7297E-6C84-4138-A9FE-3598234004E6@nvidia.com
Link: https://lkml.kernel.org/r/20220425143118.2850746-4-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Ren <renzhengeek@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Use pageblock_order for cma and alloc_contig_range alignment", v11.
This patchset tries to remove the MAX_ORDER-1 alignment requirement for CMA
and alloc_contig_range(). It prepares for my upcoming changes to make
MAX_ORDER adjustable at boot time[1].
The MAX_ORDER - 1 alignment requirement comes from that
alloc_contig_range() isolates pageblocks to remove free memory from buddy
allocator but isolating only a subset of pageblocks within a page spanning
across multiple pageblocks causes free page accounting issues. Isolated
page might not be put into the right free list, since the code assumes the
migratetype of the first pageblock as the whole free page migratetype.
This is based on the discussion at [2].
To remove the requirement, this patchset:
1. isolates pages at pageblock granularity instead of
max(MAX_ORDER_NR_PAEGS, pageblock_nr_pages);
2. splits free pages across the specified range or migrates in-use pages
across the specified range then splits the freed page to avoid free page
accounting issues (it happens when multiple pageblocks within a single page
have different migratetypes);
3. only checks unmovable pages within the range instead of MAX_ORDER - 1 aligned
range during isolation to avoid alloc_contig_range() failure when pageblocks
within a MAX_ORDER - 1 aligned range are allocated separately.
4. returns pages not in the range as it did before.
One optimization might come later:
1. make MIGRATE_ISOLATE a separate bit to be able to restore the original
migratetypes when isolation fails in the middle of the range.
[1] https://lore.kernel.org/linux-mm/20210805190253.2795604-1-zi.yan@sent.com/
[2] https://lore.kernel.org/linux-mm/d19fb078-cb9b-f60f-e310-fdeea1b947d2@redhat.com/
This patch (of 6):
has_unmovable_pages() is only used in mm/page_isolation.c. Move it from
mm/page_alloc.c and make it static.
Link: https://lkml.kernel.org/r/20220425143118.2850746-2-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Eric Ren <renzhengeek@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We've had all the necessary changes ready for both shmem and hugetlbfs.
Turn on all the shmem/hugetlbfs switches for userfaultfd-wp.
We can expand UFFD_API_RANGE_IOCTLS_BASIC with _UFFDIO_WRITEPROTECT too
because all existing types now support write protection mode.
Since vma_can_userfault() will be used elsewhere, move into userfaultfd_k.h.
Link: https://lkml.kernel.org/r/20220405014926.15101-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Firstly, we'll need to pass in dst_vma into copy_hugetlb_page_range()
because for uffd-wp it's the dst vma that matters on deciding how we
should treat uffd-wp protected ptes.
We should recognize pte markers during fork and do the pte copy if needed.
[lkp@intel.com: vma_needs_copy can be static]
Link: https://lkml.kernel.org/r/Ylb0CGeFJlc4EzLk@7ec4ff11d4ae
Link: https://lkml.kernel.org/r/20220405014918.14932-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
As with shmem uffd-wp special ptes, only drop the uffd-wp special swap pte
if unmapping an entire vma or synchronized such that faults can not race
with the unmap operation. This requires passing zap_flags all the way to
the lowest level hugetlb unmap routine: __unmap_hugepage_range.
In general, unmap calls originated in hugetlbfs code will pass the
ZAP_FLAG_DROP_MARKER flag as synchronization is in place to prevent
faults. The exception is hole punch which will first unmap without any
synchronization. Later when hole punch actually removes the page from the
file, it will check to see if there was a subsequent fault and if so take
the hugetlb fault mutex while unmapping again. This second unmap will
pass in ZAP_FLAG_DROP_MARKER.
The justification of "whether to apply ZAP_FLAG_DROP_MARKER flag when
unmap a hugetlb range" is (IMHO): we should never reach a state when a
page fault could errornously fault in a page-cache page that was
wr-protected to be writable, even in an extremely short period. That
could happen if e.g. we pass ZAP_FLAG_DROP_MARKER when
hugetlbfs_punch_hole() calls hugetlb_vmdelete_list(), because if a page
faults after that call and before remove_inode_hugepages() is executed,
the page cache can be mapped writable again in the small racy window, that
can cause unexpected data overwritten.
[peterx@redhat.com: fix sparse warning]
Link: https://lkml.kernel.org/r/Ylcdw8I1L5iAoWhb@xz-m1.local
[akpm@linux-foundation.org: move zap_flags_t from mm.h to mm_types.h to fix build issues]
Link: https://lkml.kernel.org/r/20220405014915.14873-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This starts from passing cp_flags into hugetlb_change_protection() so
hugetlb will be able to handle MM_CP_UFFD_WP[_RESOLVE] requests.
huge_pte_clear_uffd_wp() is introduced to handle the case where the
UFFDIO_WRITEPROTECT is requested upon migrating huge page entries.
Link: https://lkml.kernel.org/r/20220405014906.14708-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Pass the wp_copy variable into hugetlb_mcopy_atomic_pte() thoughout the
stack. Apply the UFFD_WP bit if UFFDIO_COPY_MODE_WP is with UFFDIO_COPY.
Hugetlb pages are only managed by hugetlbfs, so we're safe even without
setting dirty bit in the huge pte if the page is installed as read-only.
However we'd better still keep the dirty bit set for a read-only
UFFDIO_COPY pte (when UFFDIO_COPY_MODE_WP bit is set), not only to match
what we do with shmem, but also because the page does contain dirty data
that the kernel just copied from the userspace.
Link: https://lkml.kernel.org/r/20220405014904.14643-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
File-backed memory is prone to being unmapped at any time. It means all
information in the pte will be dropped, including the uffd-wp flag.
To persist the uffd-wp flag, we'll use the pte markers. This patch
teaches the zap code to understand uffd-wp and know when to keep or drop
the uffd-wp bit.
Add a new flag ZAP_FLAG_DROP_MARKER and set it in zap_details when we
don't want to persist such an information, for example, when destroying
the whole vma, or punching a hole in a shmem file. For the rest cases we
should never drop the uffd-wp bit, or the wr-protect information will get
lost.
The new ZAP_FLAG_DROP_MARKER needs to be put into mm.h rather than
memory.c because it'll be further referenced in hugetlb files later.
Link: https://lkml.kernel.org/r/20220405014847.14295-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
File-backed memories are prone to unmap/swap so the ptes are always
unstable, because they can be easily faulted back later using the page
cache. This could lead to uffd-wp getting lost when unmapping or swapping
out such memory. One example is shmem. PTE markers are needed to store
those information.
This patch prepares it by handling uffd-wp pte markers first it is applied
elsewhere, so that the page fault handler can recognize uffd-wp pte
markers.
The handling of uffd-wp pte markers is similar to missing fault, it's just
that we'll handle this "missing fault" when we see the pte markers,
meanwhile we need to make sure the marker information is kept during
processing the fault.
This is a slow path of uffd-wp handling, because zapping of wr-protected
shmem ptes should be rare. So far it should only trigger in two
conditions:
(1) When trying to punch holes in shmem_fallocate(), there is an
optimization to zap the pgtables before evicting the page.
(2) When swapping out shmem pages.
Because of this, the page fault handling is simplifed too by not sending
the wr-protect message in the 1st page fault, instead the page will be
installed read-only, so the uffd-wp message will be generated in the next
fault, which will trigger the do_wp_page() path of general uffd-wp
handling.
Disable fault-around for all uffd-wp registered ranges for extra safety
just like uffd-minor fault, and clean the code up.
Link: https://lkml.kernel.org/r/20220405014844.14239-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Pass wp_copy into shmem_mfill_atomic_pte() through the stack, then apply
the UFFD_WP bit properly when the UFFDIO_COPY on shmem is with
UFFDIO_COPY_MODE_WP. wp_copy lands mfill_atomic_install_pte() finally.
Note: we must do pte_wrprotect() if !writable in
mfill_atomic_install_pte(), as mk_pte() could return a writable pte (e.g.,
when VM_SHARED on a shmem file).
Link: https://lkml.kernel.org/r/20220405014841.14185-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patch introduces the 1st user of pte marker: the uffd-wp marker.
When the pte marker is installed with the uffd-wp bit set, it means this
pte was wr-protected by uffd.
We will use this special pte to arm the ptes that got either unmapped or
swapped out for a file-backed region that was previously wr-protected.
This special pte could trigger a page fault just like swap entries.
This idea is greatly inspired by Hugh and Andrea in the discussion, which
is referenced in the links below.
Some helpers are introduced to detect whether a swap pte is uffd
wr-protected. After the pte marker introduced, one swap pte can be
wr-protected in two forms: either it is a normal swap pte and it has
_PAGE_SWP_UFFD_WP set, or it's a pte marker that has PTE_MARKER_UFFD_WP
set.
[peterx@redhat.com: fixup]
Link: https://lkml.kernel.org/r/YkzKiM8tI4+qOfXF@xz-m1.local
Link: https://lore.kernel.org/lkml/20201126222359.8120-1-peterx@redhat.com/
Link: https://lore.kernel.org/lkml/20201130230603.46187-1-peterx@redhat.com/
Link: https://lkml.kernel.org/r/20220405014838.14131-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This patch allows do_fault() to trigger on !pte_none() cases too. This
prepares for the pte markers to be handled by do_fault() just like none
pte.
To achieve this, instead of unconditionally check against pte_none() in
finish_fault(), we may hit the case that the orig_pte was some pte marker
so what we want to do is to replace the pte marker with some valid pte
entry. Then if orig_pte was set we'd want to check the current *pte
(under pgtable lock) against orig_pte rather than none pte.
Right now there's no solid way to safely reference orig_pte because when
pmd is not allocated handle_pte_fault() will not initialize orig_pte, so
it's not safe to reference it.
There's another solution proposed before this patch to do pte_clear() for
vmf->orig_pte for pmd==NULL case, however it turns out it'll break arm32
because arm32 could have assumption that pte_t* pointer will always reside
on a real ram32 pgtable, not any kernel stack variable.
To solve this, we add a new flag FAULT_FLAG_ORIG_PTE_VALID, and it'll be
set along with orig_pte when there is valid orig_pte, or it'll be cleared
when orig_pte was not initialized.
It'll be updated every time we call handle_pte_fault(), so e.g. if a page
fault retry happened it'll be properly updated along with orig_pte.
[1] https://lore.kernel.org/lkml/710c48c9-406d-e4c5-a394-10501b951316@samsung.com/
[akpm@linux-foundation.org: coding-style cleanups]
[peterx@redhat.com: fix crash reported by Marek]
Link: https://lkml.kernel.org/r/Ylb9rXJyPm8/ao8f@xz-m1.local
Link: https://lkml.kernel.org/r/20220405014836.14077-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "userfaultfd-wp: Support shmem and hugetlbfs", v8.
Overview
========
Userfaultfd-wp anonymous support was merged two years ago. There're quite
a few applications that started to leverage this capability either to take
snapshots for user-app memory, or use it for full user controled swapping.
This series tries to complete the feature for uffd-wp so as to cover all
the RAM-based memory types. So far uffd-wp is the only missing piece of
the rest features (uffd-missing & uffd-minor mode).
One major reason to do so is that anonymous pages are sometimes not
satisfying the need of applications, and there're growing users of either
shmem and hugetlbfs for either sharing purpose (e.g., sharing guest mem
between hypervisor process and device emulation process, shmem local live
migration for upgrades), or for performance on tlb hits.
All these mean that if a uffd-wp app wants to switch to any of the memory
types, it'll stop working. I think it's worthwhile to have the kernel to
cover all these aspects.
This series chose to protect pages in pte level not page level.
One major reason is safety. I have no idea how we could make it safe if
any of the uffd-privileged app can wr-protect a page that any other
application can use. It means this app can block any process potentially
for any time it wants.
The other reason is that it aligns very well with not only the anonymous
uffd-wp solution, but also uffd as a whole. For example, userfaultfd is
implemented fundamentally based on VMAs. We set flags to VMAs showing the
status of uffd tracking. For another per-page based protection solution,
it'll be crossing the fundation line on VMA-based, and it could simply be
too far away already from what's called userfaultfd.
PTE markers
===========
The patchset is based on the idea called PTE markers. It was discussed in
one of the mm alignment sessions, proposed starting from v6, and this is
the 2nd version of it using PTE marker idea.
PTE marker is a new type of swap entry that is ony applicable to file
backed memories like shmem and hugetlbfs. It's used to persist some
pte-level information even if the original present ptes in pgtable are
zapped.
Logically pte markers can store more than uffd-wp information, but so far
only one bit is used for uffd-wp purpose. When the pte marker is
installed with uffd-wp bit set, it means this pte is wr-protected by uffd.
It solves the problem on e.g. file-backed memory mapped ptes got zapped
due to any reason (e.g. thp split, or swapped out), we can still keep the
wr-protect information in the ptes. Then when the page fault triggers
again, we'll know this pte is wr-protected so we can treat the pte the
same as a normal uffd wr-protected pte.
The extra information is encoded into the swap entry, or swp_offset to be
explicit, with the swp_type being PTE_MARKER. So far uffd-wp only uses
one bit out of the swap entry, the rest bits of swp_offset are still
reserved for other purposes.
There're two configs to enable/disable PTE markers:
CONFIG_PTE_MARKER
CONFIG_PTE_MARKER_UFFD_WP
We can set !PTE_MARKER to completely disable all the PTE markers, along
with uffd-wp support. I made two config so we can also enable PTE marker
but disable uffd-wp file-backed for other purposes. At the end of current
series, I'll enable CONFIG_PTE_MARKER by default, but that patch is
standalone and if anyone worries about having it by default, we can also
consider turn it off by dropping that oneliner patch. So far I don't see
a huge risk of doing so, so I kept that patch.
In most cases, PTE markers should be treated as none ptes. It is because
that unlike most of the other swap entry types, there's no PFN or block
offset information encoded into PTE markers but some extra well-defined
bits showing the status of the pte. These bits should only be used as
extra data when servicing an upcoming page fault, and then we behave as if
it's a none pte.
I did spend a lot of time observing all the pte_none() users this time.
It is indeed a challenge because there're a lot, and I hope I didn't miss
a single of them when we should take care of pte markers. Luckily, I
don't think it'll need to be considered in many cases, for example: boot
code, arch code (especially non-x86), kernel-only page handlings (e.g.
CPA), or device driver codes when we're tackling with pure PFN mappings.
I introduced pte_none_mostly() in this series when we need to handle pte
markers the same as none pte, the "mostly" is the other way to write
"either none pte or a pte marker".
I didn't replace pte_none() to cover pte markers for below reasons:
- Very rare case of pte_none() callers will handle pte markers. E.g., all
the kernel pages do not require knowledge of pte markers. So we don't
pollute the major use cases.
- Unconditionally change pte_none() semantics could confuse people, because
pte_none() existed for so long a time.
- Unconditionally change pte_none() semantics could make pte_none() slower
even if in many cases pte markers do not exist.
- There're cases where we'd like to handle pte markers differntly from
pte_none(), so a full replace is also impossible. E.g. khugepaged should
still treat pte markers as normal swap ptes rather than none ptes, because
pte markers will always need a fault-in to merge the marker with a valid
pte. Or the smap code will need to parse PTE markers not none ptes.
Patch Layout
============
Introducing PTE marker and uffd-wp bit in PTE marker:
mm: Introduce PTE_MARKER swap entry
mm: Teach core mm about pte markers
mm: Check against orig_pte for finish_fault()
mm/uffd: PTE_MARKER_UFFD_WP
Adding support for shmem uffd-wp:
mm/shmem: Take care of UFFDIO_COPY_MODE_WP
mm/shmem: Handle uffd-wp special pte in page fault handler
mm/shmem: Persist uffd-wp bit across zapping for file-backed
mm/shmem: Allow uffd wr-protect none pte for file-backed mem
mm/shmem: Allows file-back mem to be uffd wr-protected on thps
mm/shmem: Handle uffd-wp during fork()
Adding support for hugetlbfs uffd-wp:
mm/hugetlb: Introduce huge pte version of uffd-wp helpers
mm/hugetlb: Hook page faults for uffd write protection
mm/hugetlb: Take care of UFFDIO_COPY_MODE_WP
mm/hugetlb: Handle UFFDIO_WRITEPROTECT
mm/hugetlb: Handle pte markers in page faults
mm/hugetlb: Allow uffd wr-protect none ptes
mm/hugetlb: Only drop uffd-wp special pte if required
mm/hugetlb: Handle uffd-wp during fork()
Misc handling on the rest mm for uffd-wp file-backed:
mm/khugepaged: Don't recycle vma pgtable if uffd-wp registered
mm/pagemap: Recognize uffd-wp bit for shmem/hugetlbfs
Enabling of uffd-wp on file-backed memory:
mm/uffd: Enable write protection for shmem & hugetlbfs
mm: Enable PTE markers by default
selftests/uffd: Enable uffd-wp for shmem/hugetlbfs
Tests
=====
- Compile test on x86_64 and aarch64 on different configs
- Kernel selftests
- uffd-test [0]
- Umapsort [1,2] test for shmem/hugetlb, with swap on/off
[0] https://github.com/xzpeter/clibs/tree/master/uffd-test
[1] https://github.com/xzpeter/umap-apps/tree/peter
[2] https://github.com/xzpeter/umap/tree/peter-shmem-hugetlbfs
This patch (of 23):
Introduces a new swap entry type called PTE_MARKER. It can be installed
for any pte that maps a file-backed memory when the pte is temporarily
zapped, so as to maintain per-pte information.
The information that kept in the pte is called a "marker". Here we define
the marker as "unsigned long" just to match pgoff_t, however it will only
work if it still fits in swp_offset(), which is e.g. currently 58 bits on
x86_64.
A new config CONFIG_PTE_MARKER is introduced too; it's by default off. A
bunch of helpers are defined altogether to service the rest of the pte
marker code.
[peterx@redhat.com: fixup]
Link: https://lkml.kernel.org/r/Yk2rdB7SXZf+2BDF@xz-m1.local
Link: https://lkml.kernel.org/r/20220405014646.13522-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20220405014646.13522-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This commit moves 'damon_set_regions()' from vaddr to core, as it is aimed
to be used by not only 'vaddr' but also other parts of DAMON.
Link: https://lkml.kernel.org/r/20220429160606.127307-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: Support online tuning".
Effects of DAMON and DAMON-based Operation Schemes highly depends on the
configurations. Wrong configurations could even result in unexpected
efficiency degradations. For finding a best configuration, repeating
incremental configuration changes and results measurements, in other
words, online tuning, could be helpful.
Nevertheless, DAMON kernel API supports only restrictive online tuning.
Worse yet, the sysfs-based DAMON user interface doesn't support online
tuning at all. DAMON_RECLAIM also doesn't support online tuning.
This patchset makes the DAMON kernel API, DAMON sysfs interface, and
DAMON_RECLAIM supports online tuning.
Sequence of patches
-------------------
First two patches enhance DAMON online tuning for kernel API users.
Specifically, patch 1 let kernel API users to be able to do DAMON online
tuning without a restriction, and patch 2 makes error handling easier.
Following seven patches (patches 3-9) refactor code for better readability
and easier reuse of code fragments that will be useful for online tuning
support.
Patch 10 introduces DAMON callback based user request handling structure
for DAMON sysfs interface, and patch 11 enables DAMON online tuning via
DAMON sysfs interface. Documentation patch (patch 12) for usage of it
follows.
Patch 13 enables online tuning of DAMON_RECLAIM and finally patch 14
documents the DAMON_RECLAIM online tuning usage.
This patch (of 14):
For updating input parameters for running DAMON contexts, DAMON kernel API
users can use the contexts' callbacks, as it is the safe place for context
internal data accesses. When the context has DAMON-based operation
schemes and all schemes are deactivated due to their watermarks, however,
DAMON does nothing but only watermarks checks. As a result, no callbacks
will be called back, and therefore the kernel API users cannot update the
input parameters including monitoring attributes, DAMON-based operation
schemes, and watermarks.
To let users easily update such DAMON input parameters in such a case,
this commit adds a new callback, 'after_wmarks_check()'. It will be
called after each watermarks check. Users can do the online input
parameters update in the callback even under the schemes deactivated case.
Link: https://lkml.kernel.org/r/20220429160606.127307-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A pmd migration entry should first be a swap pmd,so use is_swap_pmd(pmd)
instead of !pmd_present(pmd).
On the other hand, some architecture (MIPS for example) may misjudge a
pmd_none entry as a pmd migration entry.
Link: https://lkml.kernel.org/r/1651131333-6386-1-git-send-email-zhanghongchen@loongson.cn
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When CONFIG_KASAN_HW_TAGS is enabled we currently increase the minimum
slab alignment to 16. This happens even if MTE is not supported in
hardware or disabled via kasan=off, which creates an unnecessary memory
overhead in those cases. Eliminate this overhead by making the minimum
slab alignment a runtime property and only aligning to 16 if KASAN is
enabled at runtime.
On a DragonBoard 845c (non-MTE hardware) with a kernel built with
CONFIG_KASAN_HW_TAGS, waiting for quiescence after a full Android boot I
see the following Slab measurements in /proc/meminfo (median of 3
reboots):
Before: 169020 kB
After: 167304 kB
[akpm@linux-foundation.org: make slab alignment type `unsigned int' to avoid casting]
Link: https://linux-review.googlesource.com/id/I752e725179b43b144153f4b6f584ceb646473ead
Link: https://lkml.kernel.org/r/20220427195820.1716975-2-pcc@google.com
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
