| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
vma->lock being part of the vm_area_struct causes performance regression
during page faults because during contention its count and owner fields
are constantly updated and having other parts of vm_area_struct used
during page fault handling next to them causes constant cache line
bouncing. Fix that by moving the lock outside of the vm_area_struct.
All attempts to keep vma->lock inside vm_area_struct in a separate cache
line still produce performance regression especially on NUMA machines.
Smallest regression was achieved when lock is placed in the fourth cache
line but that bloats vm_area_struct to 256 bytes.
Considering performance and memory impact, separate lock looks like the
best option. It increases memory footprint of each VMA but that can be
optimized later if the new size causes issues. Note that after this
change vma_init() does not allocate or initialize vma->lock anymore. A
number of drivers allocate a pseudo VMA on the stack but they never use
the VMA's lock, therefore it does not need to be allocated. The future
drivers which might need the VMA lock should use
vm_area_alloc()/vm_area_free() to allocate the VMA.
Link: https://lkml.kernel.org/r/20230227173632.3292573-34-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
call_rcu() can take a long time when callback offloading is enabled. Its
use in the vm_area_free can cause regressions in the exit path when
multiple VMAs are being freed.
Because exit_mmap() is called only after the last mm user drops its
refcount, the page fault handlers can't be racing with it. Any other
possible user like oom-reaper or process_mrelease are already synchronized
using mmap_lock. Therefore exit_mmap() can free VMAs directly, without
the use of call_rcu().
Expose __vm_area_free() and use it from exit_mmap() to avoid possible
call_rcu() floods and performance regressions caused by it.
Link: https://lkml.kernel.org/r/20230227173632.3292573-33-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Assert there are no holders of VMA lock for reading when it is about to be
destroyed.
Link: https://lkml.kernel.org/r/20230227173632.3292573-21-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Introduce per-VMA locking. The lock implementation relies on a per-vma
and per-mm sequence counters to note exclusive locking:
- read lock - (implemented by vma_start_read) requires the vma
(vm_lock_seq) and mm (mm_lock_seq) sequence counters to differ.
If they match then there must be a vma exclusive lock held somewhere.
- read unlock - (implemented by vma_end_read) is a trivial vma->lock
unlock.
- write lock - (vma_start_write) requires the mmap_lock to be held
exclusively and the current mm counter is assigned to the vma counter.
This will allow multiple vmas to be locked under a single mmap_lock
write lock (e.g. during vma merging). The vma counter is modified
under exclusive vma lock.
- write unlock - (vma_end_write_all) is a batch release of all vma
locks held. It doesn't pair with a specific vma_start_write! It is
done before exclusive mmap_lock is released by incrementing mm
sequence counter (mm_lock_seq).
- write downgrade - if the mmap_lock is downgraded to the read lock, all
vma write locks are released as well (effectivelly same as write
unlock).
Link: https://lkml.kernel.org/r/20230227173632.3292573-13-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This prepares for page faults handling under VMA lock, looking up VMAs
under protection of an rcu read lock, instead of the usual mmap read lock.
Link: https://lkml.kernel.org/r/20230227173632.3292573-11-surenb@google.com
Signed-off-by: Michel Lespinasse <michel@lespinasse.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use the maple tree in RCU mode for VMA tracking.
The maple tree tracks the stack and is able to update the pivot
(lower/upper boundary) in-place to allow the page fault handler to write
to the tree while holding just the mmap read lock. This is safe as the
writes to the stack have a guard VMA which ensures there will always be a
NULL in the direction of the growth and thus will only update a pivot.
It is possible, but not recommended, to have VMAs that grow up/down
without guard VMAs. syzbot has constructed a testcase which sets up a VMA
to grow and consume the empty space. Overwriting the entire NULL entry
causes the tree to be altered in a way that is not safe for concurrent
readers; the readers may see a node being rewritten or one that does not
match the maple state they are using.
Enabling RCU mode allows the concurrent readers to see a stable node and
will return the expected result.
[Liam.Howlett@Oracle.com: we don't need to free the nodes with RCU[
Link: https://lore.kernel.org/linux-mm/000000000000b0a65805f663ace6@google.com/
Link: https://lkml.kernel.org/r/20230227173632.3292573-9-surenb@google.com
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: syzbot+8d95422d3537159ca390@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Stop open-coding get_unused_fd_flags() and anon_inode_getfile(). That's
brittle just for keeping the flags between both calls in sync. Use the
dedicated helper.
Message-Id: <20230327-pidfd-file-api-v1-2-5c0e9a3158e4@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Add a new helper that allows to reserve a pidfd and allocates a new
pidfd file that stashes the provided struct pid. This will allow us to
remove places that either open code this function or that call
pidfd_create() but then have to call close_fd() because there are still
failure points after pidfd_create() has been called.
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230327-pidfd-file-api-v1-1-5c0e9a3158e4@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Preparing to remove IOASID infrastructure, PASID management will be
under SVA code. Decouple mm code from IOASID.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230322200803.869130-3-jacob.jun.pan@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
|
|
During tracefs discussions it was decided instead of requiring a mapping
within a user-process to track the lifetime of memory descriptors we
should hook the appropriate calls. Do this by adding the minimal stubs
required for task fork, exec, and exit. Currently this is just a NOP.
Future patches will implement these calls fully.
Link: https://lkml.kernel.org/r/20230328235219.203-3-beaub@linux.microsoft.com
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
On big systems, the mm refcount can become highly contented when doing a
lot of context switching with threaded applications. user<->idle switch
is one of the important cases. Abandoning lazy tlb entirely slows this
switching down quite a bit in the common uncontended case, so that is not
viable.
Implement a scheme where lazy tlb mm references do not contribute to the
refcount, instead they get explicitly removed when the refcount reaches
zero.
The final mmdrop() sends IPIs to all CPUs in the mm_cpumask and they
switch away from this mm to init_mm if it was being used as the lazy tlb
mm. Enabling the shoot lazies option therefore requires that the arch
ensures that mm_cpumask contains all CPUs that could possibly be using mm.
A DEBUG_VM option IPIs every CPU in the system after this to ensure there
are no references remaining before the mm is freed.
Shootdown IPIs cost could be an issue, but they have not been observed to
be a serious problem with this scheme, because short-lived processes tend
not to migrate CPUs much, therefore they don't get much chance to leave
lazy tlb mm references on remote CPUs. There are a lot of options to
reduce them if necessary, described in comments.
The near-worst-case can be benchmarked with will-it-scale:
context_switch1_threads -t $(($(nproc) / 2))
This will create nproc threads (nproc / 2 switching pairs) all sharing the
same mm that spread over all CPUs so each CPU does thread->idle->thread
switching.
[ Rik came up with basically the same idea a few years ago, so credit
to him for that. ]
Link: https://lore.kernel.org/linux-mm/20230118080011.2258375-1-npiggin@gmail.com/
Link: https://lore.kernel.org/all/20180728215357.3249-11-riel@surriel.com/
Link: https://lkml.kernel.org/r/20230203071837.1136453-5-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Pull xfs percpu counter fixes from Darrick Wong:
"We discovered a filesystem summary counter corruption problem that was
traced to cpu hot-remove racing with the call to percpu_counter_sum
that sets the free block count in the superblock when writing it to
disk. The root cause is that percpu_counter_sum doesn't cull from
dying cpus and hence misses those counter values if the cpu shutdown
hooks have not yet run to merge the values.
I'm hoping this is a fairly painless fix to the problem, since the
dying cpu mask should generally be empty. It's been in for-next for a
week without any complaints from the bots.
- Fix a race in the percpu counters summation code where the
summation failed to add in the values for any CPUs that were dying
but not yet dead. This fixes some minor discrepancies and incorrect
assertions when running generic/650"
* tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
pcpcntr: remove percpu_counter_sum_all()
fork: remove use of percpu_counter_sum_all
pcpcntrs: fix dying cpu summation race
cpumask: introduce for_each_cpu_or
|
|
This effectively reverts the change made in commit f689054aace2
("percpu_counter: add percpu_counter_sum_all interface") as the
race condition percpu_counter_sum_all() was invented to avoid is
now handled directly in percpu_counter_sum() and nobody needs to
care about summing racing with cpu unplug anymore.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
|
|
The next patch adds helpers like create_io_thread, but for use by the
vhost layer. There are several functions, so they are in their own file
instead of cluttering up fork.c. This patch allows that new file to
call copy_process.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Since:
commit 10ab825bdef8 ("change kernel threads to ignore signals instead of
blocking them")
kthreads have been ignoring signals by default, and the vhost layer has
never had a need to change that. This patch adds an option flag,
USER_WORKER_SIG_IGN, handled in copy_process() after copy_sighand()
and copy_signals() so vhost_tasks added in the next patches can continue
to ignore singals.
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Each vhost device gets a thread that is used to perform IO and management
operations. Instead of a thread that is accessing a device, the thread is
part of the device, so when it creates a thread using a helper based on
copy_process we can't dup or clone the parent's files/FDS because it
would do an extra increment on ourself.
Later, when we do:
Qemu process exits:
do_exit -> exit_files -> put_files_struct -> close_files
we would leak the device's resources because of that extra refcount
on the fd or file_struct.
This patch adds a no_files option so these worker threads can prevent
taking an extra refcount on themselves.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
This adds a new flag, PF_USER_WORKER, that's used for behavior common to
to both PF_IO_WORKER and users like vhost which will use a new helper
instead of create_io_thread because they require different behavior for
operations like signal handling.
The common behavior PF_USER_WORKER covers is the vm reclaim handling.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
This patch allows kernel users to pass in the thread name so it can be
set during creation instead of having to use set_task_comm after the
thread is created.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Currently, calling clone3() with CLONE_NEWTIME in clone_args->flags
fails with -EINVAL. This is because CLONE_NEWTIME intersects with
CSIGNAL. However, CSIGNAL was deprecated when clone3 was introduced in
commit 7f192e3cd316 ("fork: add clone3"), allowing re-use of that part
of clone flags.
Fix this by explicitly allowing CLONE_NEWTIME in clone3_args_valid. This
is also in line with the respective check in check_unshare_flags which
allow CLONE_NEWTIME for unshare().
Fixes: 769071ac9f20 ("ns: Introduce Time Namespace")
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Improve the scalability of the CFS bandwidth unthrottling logic with
large number of CPUs.
- Fix & rework various cpuidle routines, simplify interaction with the
generic scheduler code. Add __cpuidle methods as noinstr to objtool's
noinstr detection and fix boatloads of cpuidle bugs & quirks.
- Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS, to query
previously issued registrations.
- Limit scheduler slice duration to the sysctl_sched_latency period, to
improve scheduling granularity with a large number of SCHED_IDLE
tasks.
- Debuggability enhancement on sys_exit(): warn about disabled IRQs,
but also enable them to prevent a cascade of followup problems and
repeat warnings.
- Fix the rescheduling logic in prio_changed_dl().
- Micro-optimize cpufreq and sched-util methods.
- Micro-optimize ttwu_runnable()
- Micro-optimize the idle-scanning in update_numa_stats(),
select_idle_capacity() and steal_cookie_task().
- Update the RSEQ code & self-tests
- Constify various scheduler methods
- Remove unused methods
- Refine __init tags
- Documentation updates
- Misc other cleanups, fixes
* tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
sched/rt: pick_next_rt_entity(): check list_entry
sched/deadline: Add more reschedule cases to prio_changed_dl()
sched/fair: sanitize vruntime of entity being placed
sched/fair: Remove capacity inversion detection
sched/fair: unlink misfit task from cpu overutilized
objtool: mem*() are not uaccess safe
cpuidle: Fix poll_idle() noinstr annotation
sched/clock: Make local_clock() noinstr
sched/clock/x86: Mark sched_clock() noinstr
x86/pvclock: Improve atomic update of last_value in pvclock_clocksource_read()
x86/atomics: Always inline arch_atomic64*()
cpuidle: tracing, preempt: Squash _rcuidle tracing
cpuidle: tracing: Warn about !rcu_is_watching()
cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG
cpuidle: drivers: firmware: psci: Dont instrument suspend code
KVM: selftests: Fix build of rseq test
exit: Detect and fix irq disabled state in oops
cpuidle, arm64: Fix the ARM64 cpuidle logic
cpuidle: mvebu: Fix duplicate flags assignment
sched/fair: Limit sched slice duration
...
|
|
To simplify the usage of VM_LOCKED_CLEAR_MASK in vm_flags_clear(), replace
it with VM_LOCKED_MASK bitmask and convert all users.
Link: https://lkml.kernel.org/r/20230126193752.297968-4-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "introduce vm_flags modifier functions", v4.
This patchset was originally published as a part of per-VMA locking [1]
and was split after suggestion that it's viable on its own and to
facilitate the review process. It is now a preprequisite for the next
version of per-VMA lock patchset, which reuses vm_flags modifier functions
to lock the VMA when vm_flags are being updated.
VMA vm_flags modifications are usually done under exclusive mmap_lock
protection because this attrubute affects other decisions like VMA merging
or splitting and races should be prevented. Introduce vm_flags modifier
functions to enforce correct locking.
This patch (of 7):
Convert vma assignment in vm_area_dup() to a memcpy() to prevent compiler
errors when we add a const modifier to vma->vm_flags.
Link: https://lkml.kernel.org/r/20230126193752.297968-1-surenb@google.com
Link: https://lkml.kernel.org/r/20230126193752.297968-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Avoid using the maple tree interface directly. This gains type safety.
Link: https://lkml.kernel.org/r/20230120162650.984577-10-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Switch from a request_queue pointer and reference to a gendisk once
for the throttle information in struct task_struct.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Link: https://lore.kernel.org/r/20230203150400.3199230-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
This feature allows the scheduler to expose a per-memory map concurrency
ID to user-space. This concurrency ID is within the possible cpus range,
and is temporarily (and uniquely) assigned while threads are actively
running within a memory map. If a memory map has fewer threads than
cores, or is limited to run on few cores concurrently through sched
affinity or cgroup cpusets, the concurrency IDs will be values close
to 0, thus allowing efficient use of user-space memory for per-cpu
data structures.
This feature is meant to be exposed by a new rseq thread area field.
The primary purpose of this feature is to do the heavy-lifting needed
by memory allocators to allow them to use per-cpu data structures
efficiently in the following situations:
- Single-threaded applications,
- Multi-threaded applications on large systems (many cores) with limited
cpu affinity mask,
- Multi-threaded applications on large systems (many cores) with
restricted cgroup cpuset per container.
One of the key concern from scheduler maintainers is the overhead
associated with additional spin locks or atomic operations in the
scheduler fast-path. This is why the following optimization is
implemented.
On context switch between threads belonging to the same memory map,
transfer the mm_cid from prev to next without any atomic ops. This
takes care of use-cases involving frequent context switch between
threads belonging to the same memory map.
Additional optimizations can be done if the spin locks added when
context switching between threads belonging to different memory maps end
up being a performance bottleneck. Those are left out of this patch
though. A performance impact would have to be clearly demonstrated to
justify the added complexity.
The credit goes to Paul Turner (Google) for the original virtual cpu id
idea. This feature is implemented based on the discussions with Paul
Turner and Peter Oskolkov (Google), but I took the liberty to implement
scheduler fast-path optimizations and my own NUMA-awareness scheme. The
rumor has it that Google have been running a rseq vcpu_id extension
internally in production for a year. The tcmalloc source code indeed has
comments hinting at a vcpu_id prototype extension to the rseq system
call [1].
The following benchmarks do not show any significant overhead added to
the scheduler context switch by this feature:
* perf bench sched messaging (process)
Baseline: 86.5±0.3 ms
With mm_cid: 86.7±2.6 ms
* perf bench sched messaging (threaded)
Baseline: 84.3±3.0 ms
With mm_cid: 84.7±2.6 ms
* hackbench (process)
Baseline: 82.9±2.7 ms
With mm_cid: 82.9±2.9 ms
* hackbench (threaded)
Baseline: 85.2±2.6 ms
With mm_cid: 84.4±2.9 ms
[1] https://github.com/google/tcmalloc/blob/master/tcmalloc/internal/linux_syscall_support.h#L26
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-8-mathieu.desnoyers@efficios.com
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Dave Hansen:
"New Feature:
- Randomize the per-cpu entry areas
Cleanups:
- Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it
- Move to "native" set_memory_rox() helper
- Clean up pmd_get_atomic() and i386-PAE
- Remove some unused page table size macros"
* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
x86/mm: Ensure forced page table splitting
x86/kasan: Populate shadow for shared chunk of the CPU entry area
x86/kasan: Add helpers to align shadow addresses up and down
x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
x86/mm: Recompute physical address for every page of per-CPU CEA mapping
x86/mm: Rename __change_page_attr_set_clr(.checkalias)
x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
x86/mm: Add a few comments
x86/mm: Fix CR3_ADDR_MASK
x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
mm: Convert __HAVE_ARCH_P..P_GET to the new style
mm: Remove pointless barrier() after pmdp_get_lockless()
x86/mm/pae: Get rid of set_64bit()
x86_64: Remove pointless set_64bit() usage
x86/mm/pae: Be consistent with pXXp_get_and_clear()
x86/mm/pae: Use WRITE_ONCE()
x86/mm/pae: Don't (ab)use atomic64
mm/gup: Fix the lockless PMD access
...
|
|
Instead of duplicating init_mm, allocate a fresh mm. The advantage is
that mm_alloc() has much simpler dependencies. Additionally it makes
more conceptual sense, init_mm has no (and must not have) user state
to duplicate.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.816175235@infradead.org
|
|
In order to allow using mm_alloc() much earlier, move initializing
mm_cachep into mm_init().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.751153381@infradead.org
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- More userfaultfs work from Peter Xu
- Several convert-to-folios series from Sidhartha Kumar and Huang Ying
- Some filemap cleanups from Vishal Moola
- David Hildenbrand added the ability to selftest anon memory COW
handling
- Some cpuset simplifications from Liu Shixin
- Addition of vmalloc tracing support by Uladzislau Rezki
- Some pagecache folioifications and simplifications from Matthew
Wilcox
- A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use
it
- Miguel Ojeda contributed some cleanups for our use of the
__no_sanitize_thread__ gcc keyword.
This series should have been in the non-MM tree, my bad
- Naoya Horiguchi improved the interaction between memory poisoning and
memory section removal for huge pages
- DAMON cleanups and tuneups from SeongJae Park
- Tony Luck fixed the handling of COW faults against poisoned pages
- Peter Xu utilized the PTE marker code for handling swapin errors
- Hugh Dickins reworked compound page mapcount handling, simplifying it
and making it more efficient
- Removal of the autonuma savedwrite infrastructure from Nadav Amit and
David Hildenbrand
- zram support for multiple compression streams from Sergey Senozhatsky
- David Hildenbrand reworked the GUP code's R/O long-term pinning so
that drivers no longer need to use the FOLL_FORCE workaround which
didn't work very well anyway
- Mel Gorman altered the page allocator so that local IRQs can remnain
enabled during per-cpu page allocations
- Vishal Moola removed the try_to_release_page() wrapper
- Stefan Roesch added some per-BDI sysfs tunables which are used to
prevent network block devices from dirtying excessive amounts of
pagecache
- David Hildenbrand did some cleanup and repair work on KSM COW
breaking
- Nhat Pham and Johannes Weiner have implemented writeback in zswap's
zsmalloc backend
- Brian Foster has fixed a longstanding corner-case oddity in
file[map]_write_and_wait_range()
- sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
Chen
- Shiyang Ruan has done some work on fsdax, to make its reflink mode
work better under xfstests. Better, but still not perfect
- Christoph Hellwig has removed the .writepage() method from several
filesystems. They only need .writepages()
- Yosry Ahmed wrote a series which fixes the memcg reclaim target
beancounting
- David Hildenbrand has fixed some of our MM selftests for 32-bit
machines
- Many singleton patches, as usual
* tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits)
mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio
mm: mmu_gather: allow more than one batch of delayed rmaps
mm: fix typo in struct pglist_data code comment
kmsan: fix memcpy tests
mm: add cond_resched() in swapin_walk_pmd_entry()
mm: do not show fs mm pc for VM_LOCKONFAULT pages
selftests/vm: ksm_functional_tests: fixes for 32bit
selftests/vm: cow: fix compile warning on 32bit
selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions
mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem
mm,thp,rmap: fix races between updates of subpages_mapcount
mm: memcg: fix swapcached stat accounting
mm: add nodes= arg to memory.reclaim
mm: disable top-tier fallback to reclaim on proactive reclaim
selftests: cgroup: make sure reclaim target memcg is unprotected
selftests: cgroup: refactor proactive reclaim code to reclaim_until()
mm: memcg: fix stale protection of reclaim target memcg
mm/mmap: properly unaccount memory on mas_preallocate() failure
omfs: remove ->writepage
jfs: remove ->writepage
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Replace prandom_u32_max() and various open-coded variants of it,
there is now a new family of functions that uses fast rejection
sampling to choose properly uniformly random numbers within an
interval:
get_random_u32_below(ceil) - [0, ceil)
get_random_u32_above(floor) - (floor, U32_MAX]
get_random_u32_inclusive(floor, ceil) - [floor, ceil]
Coccinelle was used to convert all current users of
prandom_u32_max(), as well as many open-coded patterns, resulting in
improvements throughout the tree.
I'll have a "late" 6.1-rc1 pull for you that removes the now unused
prandom_u32_max() function, just in case any other trees add a new
use case of it that needs to converted. According to linux-next,
there may be two trivial cases of prandom_u32_max() reintroductions
that are fixable with a 's/.../.../'. So I'll have for you a final
conversion patch doing that alongside the removal patch during the
second week.
This is a treewide change that touches many files throughout.
- More consistent use of get_random_canary().
- Updates to comments, documentation, tests, headers, and
simplification in configuration.
- The arch_get_random*_early() abstraction was only used by arm64 and
wasn't entirely useful, so this has been replaced by code that works
in all relevant contexts.
- The kernel will use and manage random seeds in non-volatile EFI
variables, refreshing a variable with a fresh seed when the RNG is
initialized. The RNG GUID namespace is then hidden from efivarfs to
prevent accidental leakage.
These changes are split into random.c infrastructure code used in the
EFI subsystem, in this pull request, and related support inside of
EFISTUB, in Ard's EFI tree. These are co-dependent for full
functionality, but the order of merging doesn't matter.
- Part of the infrastructure added for the EFI support is also used for
an improvement to the way vsprintf initializes its siphash key,
replacing an sleep loop wart.
- The hardware RNG framework now always calls its correct random.c
input function, add_hwgenerator_randomness(), rather than sometimes
going through helpers better suited for other cases.
- The add_latent_entropy() function has long been called from the fork
handler, but is a no-op when the latent entropy gcc plugin isn't
used, which is fine for the purposes of latent entropy.
But it was missing out on the cycle counter that was also being mixed
in beside the latent entropy variable. So now, if the latent entropy
gcc plugin isn't enabled, add_latent_entropy() will expand to a call
to add_device_randomness(NULL, 0), which adds a cycle counter,
without the absent latent entropy variable.
- The RNG is now reseeded from a delayed worker, rather than on demand
when used. Always running from a worker allows it to make use of the
CPU RNG on platforms like S390x, whose instructions are too slow to
do so from interrupts. It also has the effect of adding in new inputs
more frequently with more regularity, amounting to a long term
transcript of random values. Plus, it helps a bit with the upcoming
vDSO implementation (which isn't yet ready for 6.2).
- The jitter entropy algorithm now tries to execute on many different
CPUs, round-robining, in hopes of hitting even more memory latencies
and other unpredictable effects. It also will mix in a cycle counter
when the entropy timer fires, in addition to being mixed in from the
main loop, to account more explicitly for fluctuations in that timer
firing. And the state it touches is now kept within the same cache
line, so that it's assured that the different execution contexts will
cause latencies.
* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits)
random: include <linux/once.h> in the right header
random: align entropy_timer_state to cache line
random: mix in cycle counter when jitter timer fires
random: spread out jitter callback to different CPUs
random: remove extraneous period and add a missing one in comments
efi: random: refresh non-volatile random seed when RNG is initialized
vsprintf: initialize siphash key using notifier
random: add back async readiness notifier
random: reseed in delayed work rather than on-demand
random: always mix cycle counter in add_latent_entropy()
hw_random: use add_hwgenerator_randomness() for early entropy
random: modernize documentation comment on get_random_bytes()
random: adjust comment to account for removed function
random: remove early archrandom abstraction
random: use random.trust_{bootloader,cpu} command line option only
stackprotector: actually use get_random_canary()
stackprotector: move get_random_canary() into stackprotector.h
treewide: use get_random_u32_inclusive() when possible
treewide: use get_random_u32_{above,below}() instead of manual loop
treewide: use get_random_u32_below() instead of deprecated function
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve updates from Kees Cook:
"Most are small refactorings and bug fixes, but three things stand out:
switching timens (which got reverted before) looks solid now,
FOLL_FORCE has been removed (no failures seen yet across several weeks
in -next), and some whitespace cleanups (which are long overdue).
- Add timens support (when switching mm). This version has survived
in -next for the entire cycle (Andrei Vagin)
- Various small bug fixes, refactoring, and readability improvements
(Bernd Edlinger, Rolf Eike Beer, Bo Liu, Li Zetao Liu Shixin)
- Remove FOLL_FORCE for stack setup (Kees Cook)
- Whitespace cleanups (Rolf Eike Beer, Kees Cook)"
* tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
binfmt_misc: fix shift-out-of-bounds in check_special_flags
binfmt: Fix error return code in load_elf_fdpic_binary()
exec: Remove FOLL_FORCE for stack setup
binfmt_elf: replace IS_ERR() with IS_ERR_VALUE()
binfmt_elf: simplify error handling in load_elf_phdrs()
binfmt_elf: fix documented return value for load_elf_phdrs()
exec: simplify initial stack size expansion
binfmt: Fix whitespace issues
exec: Add comments on check_unsafe_exec() fs counting
ELF uapi: add spaces before '{'
selftests/timens: add a test for vfork+exit
fs/exec: switch timens when a task gets a new mm
|
|
Our syzbot instance reported memory leaks in do_seccomp() [0], similar
to the report [1]. It shows that we miss freeing struct seccomp_filter
and some objects included in it.
We can reproduce the issue with the program below [2] which calls one
seccomp() and two clone() syscalls.
The first clone()d child exits earlier than its parent and sends a
signal to kill it during the second clone(), more precisely before the
fatal_signal_pending() test in copy_process(). When the parent receives
the signal, it has to destroy the embryonic process and return -EINTR to
user space. In the failure path, we have to call seccomp_filter_release()
to decrement the filter's refcount.
Initially, we called it in free_task() called from the failure path, but
the commit 3a15fb6ed92c ("seccomp: release filter after task is fully
dead") moved it to release_task() to notify user space as early as possible
that the filter is no longer used.
To keep the change and current seccomp refcount semantics, let's move
copy_seccomp() just after the signal check and add a WARN_ON_ONCE() in
free_task() for future debugging.
[0]:
unreferenced object 0xffff8880063add00 (size 256):
comm "repro_seccomp", pid 230, jiffies 4294687090 (age 9.914s)
hex dump (first 32 bytes):
01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
backtrace:
do_seccomp (./include/linux/slab.h:600 ./include/linux/slab.h:733 kernel/seccomp.c:666 kernel/seccomp.c:708 kernel/seccomp.c:1871 kernel/seccomp.c:1991)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
unreferenced object 0xffffc90000035000 (size 4096):
comm "repro_seccomp", pid 230, jiffies 4294687090 (age 9.915s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 05 00 00 00 . |
