| Age | Commit message (Collapse) | Author | Files | Lines |
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Add an internal struct iovec that we can return as a pointer, with the
fields of the iovec overlapping with the ITER_UBUF ubuf and length
fields.
Then we can have iter_iov() check for the appropriate type, and return
&iter->__ubuf_iovec for ITER_UBUF and iter->__iov for ITER_IOVEC and
things will magically work out for a single segment request regardless
of either type.
Signed-off-by: Jens Axboe <[email protected]>
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To avoid needing to check if a given user backed iov_iter is of type
ITER_IOVEC or ITER_UBUF, set the number of segments for the ITER_UBUF
case to 1 as we're carrying a single segment.
Signed-off-by: Jens Axboe <[email protected]>
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No more users are left of this function.
Signed-off-by: Jens Axboe <[email protected]>
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These just return the address and length of the current iovec segment
in the iterator. Convert existing iov_iter_iovec() users to use them
instead of getting a copy of the current vec.
Signed-off-by: Jens Axboe <[email protected]>
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This returns a pointer to the current iovec entry in the iterator. Only
useful with ITER_IOVEC right now, but it prepares us to treat ITER_UBUF
and ITER_IOVEC identically for the first segment.
Rename struct iov_iter->iov to iov_iter->__iov to find any potentially
troublesome spots, and also to prevent anyone from adding new code that
accesses iter->iov directly.
Signed-off-by: Jens Axboe <[email protected]>
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This patch adds missing variable no_cs descriptions.
Signed-off-by: Jaewon Kim <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Andi Shyti <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
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We want to make two optimizations in napi_schedule_rps() and
____napi_schedule() which require to know if these helpers are
called from net_rx_action(), instead of being called from
other contexts.
sd.in_net_rx_action is only read/written by the owning cpu.
Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Jason Xing <[email protected]>
Tested-by: Jason Xing <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
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We've aligned setgid behavior over multiple kernel releases. The details
can be found in the following two merge messages:
cf619f891971 ("Merge tag 'fs.ovl.setgid.v6.2')
426b4ca2d6a5 ("Merge tag 'fs.setgid.v6.0')
Consistent setgid stripping behavior is now encapsulated in the
setattr_should_drop_sgid() helper which is used by all filesystems that
strip setgid bits outside of vfs proper. Switch nfs to rely on this
helper as well. Without this patch the setgid stripping tests in
xfstests will fail.
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
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Let's use BIT() and GENMASK() instead of open it.
Signed-off-by: Yangtao Li <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
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Constant battery data is available through power-supply's simple-battery
API. This works automatically, so the manual handling can be removed
without loosing any feature :)
Note, that the POWER_SUPPLY_STATUS_FULL check for the level variable can
be dropped, since the variable is never written. It can be re-introduced
properly once the driver gets functionality to calculate the current
charge level. Apart from that the check must be done fuzzy anyways,
since charge estimation usually is not precise enough to always return
exactly the full charge capacity for a full battery.
Reviewed-by: Linus Walleij <[email protected]>
Reviewed-by: Matti Vaittinen <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
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Drop CHARGE_NOW support, which requires a platform specific
calculation method.
Reviewed-by: Linus Walleij <[email protected]>
Reviewed-by: Matti Vaittinen <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
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Drop support for configuring IRQ jitter delay by using big
enough fixed value.
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
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Automatically expose data from the simple-battery firmware
node for all battery drivers.
Reviewed-by: Linus Walleij <[email protected]>
Reviewed-by: Matti Vaittinen <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
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I just landed the fence deadline PR from Rob that a bunch of drivers
want/need to apply driver-specific patches. Backmerge -rc4 so that
they don't have to be stuck on -rc2 for no reason at all.
Signed-off-by: Daniel Vetter <[email protected]>
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into drm-next
This series adds a deadline hint to fences, so realtime deadlines
such as vblank can be communicated to the fence signaller for power/
frequency management decisions.
This is partially inspired by a trick i915 does, but implemented
via dma-fence for a couple of reasons:
1) To continue to be able to use the atomic helpers
2) To support cases where display and gpu are different drivers
See https://patchwork.freedesktop.org/series/93035/
This does not yet add any UAPI, although this will be needed in
a number of cases:
1) Workloads "ping-ponging" between CPU and GPU, where we don't
want the GPU freq governor to interpret time stalled waiting
for GPU as "idle" time
2) Cases where the compositor is waiting for fences to be signaled
before issuing the atomic ioctl, for example to maintain 60fps
cursor updates even when the GPU is not able to maintain that
framerate.
Signed-off-by: Daniel Vetter <[email protected]>
From: Rob Clark <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGt5nDQpa6J86V1oFKPA30YcJzPhAVpmF7N1K1g2N3c=Zg@mail.gmail.com
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The compressed register cache support has assumptions that make it hard to
cover in testing, mainly that it requires raw registers defaults be
provided. Rather than either address these assumptions or leave it untested
by the forthcoming KUnit tests let's remove it, the use case is quite thin
and there are no current users.
Signed-off-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Add tabs to make struct members easier to read and unify the style of
the code.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Beau Belgrave <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
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As part of the discussions for user_events aligned with user space
tracers, it was determined that user programs should register a aligned
value to set or clear a bit when an event becomes enabled. Currently a
shared page is being used that requires mmap(). Remove the shared page
implementation and move to a user registered address implementation.
In this new model during the event registration from user programs 3 new
values are specified. The first is the address to update when the event
is either enabled or disabled. The second is the bit to set/clear to
reflect the event being enabled. The third is the size of the value at
the specified address.
This allows for a local 32/64-bit value in user programs to support
both kernel and user tracers. As an example, setting bit 31 for kernel
tracers when the event becomes enabled allows for user tracers to use
the other bits for ref counts or other flags. The kernel side updates
the bit atomically, user programs need to also update these values
atomically.
User provided addresses must be aligned on a natural boundary, this
allows for single page checking and prevents odd behaviors such as a
enable value straddling 2 pages instead of a single page. Currently
page faults are only logged, future patches will handle these.
Link: https://lkml.kernel.org/r/[email protected]
Suggested-by: Mathieu Desnoyers <[email protected]>
Signed-off-by: Beau Belgrave <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
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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/[email protected]
Suggested-by: Mathieu Desnoyers <[email protected]>
Signed-off-by: Beau Belgrave <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
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The UAPI parts need to be split out from the kernel parts of user_events
now that other parts of the kernel will reference it. Do so by moving
the existing include/linux/user_events.h into
include/uapi/linux/user_events.h.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Beau Belgrave <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
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On devices featuring several banks, the Read While Write (RWW) feature
is here to improve the overall performance when performing parallel
reads and writes at different locations (different banks). The following
constraints have to be taken into account:
1#: A single operation can be performed in a given bank.
2#: Only a single program or erase operation can happen on the entire
chip (common hardware limitation to limit costs)
3#: Reads must remain serialized even though reads crossing bank
boundaries are allowed.
4#: The I/O bus is unique and thus is the most constrained resource, all
spi-nor operations requiring access to the spi bus (through the spi
controller) must be serialized until the bus exchanges are over. So
we must ensure a single operation can be "sent" at a time.
5#: Any other operation that would not be either a read or a write or an
erase is considered requiring access to the full chip and cannot be
parallelized, we then need to ensure the full chip is in the idle
state when this occurs.
All these constraints can easily be managed with a proper locking model:
1#: Is enforced by a bitfield of the in-use banks, so that only a single
operation can happen in a specific bank at any time.
2#: Is handled by the ongoing_pe boolean which is set before any write
or erase, and is released only at the very end of the
operation. This way, no other destructive operation on the chip can
start during this time frame.
3#: An ongoing_rd boolean allows to track the ongoing reads, so that
only one can be performed at a time.
4#: An ongoing_io boolean is introduced in order to capture and serialize
bus accessed. This is the one being released "sooner" than before,
because we only need to protect the chip against other SPI accesses
during the I/O phase, which for the destructive operations is the
beginning of the operation (when we send the command cycles and
possibly the data), while the second part of the operation (the
erase delay or the programmation delay) is when we can do something
else in another bank.
5#: Is handled by the three booleans presented above, if any of them is
set, the chip is not yet ready for the operation and must wait.
All these internal variables are protected by the existing lock, so that
changes in this structure are atomic. The serialization is handled with
a wait queue.
Signed-off-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Tudor Ambarus <[email protected]>
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Create sysfs entry for CDX devices.
Sysfs entries provided in each of the CDX device detected by
the CDX controller
- vendor id
- device id
- remove
- reset of the device.
- driver override
Signed-off-by: Puneet Gupta <[email protected]>
Signed-off-by: Nipun Gupta <[email protected]>
Signed-off-by: Tarak Reddy <[email protected]>
Reviewed-by: Pieter Jansen van Vuuren <[email protected]>
Tested-by: Nikhil Agarwal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Introduce AMD CDX bus, which provides a mechanism for scanning
and probing CDX devices. These devices are memory mapped on
system bus for Application Processors(APUs).
CDX devices can be changed dynamically in the Fabric and CDX
bus interacts with CDX controller to rescan the bus and
rediscover the devices.
Signed-off-by: Nipun Gupta <[email protected]>
Reviewed-by: Pieter Jansen van Vuuren <[email protected]>
Tested-by: Nikhil Agarwal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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A series by myself to remove CONFIG_SLOB:
The SLOB allocator was deprecated in 6.2 and there have been no
complaints so far so let's proceed with the removal.
Besides the code cleanup, the main immediate benefit will be allowing
kfree() family of function to work on kmem_cache_alloc() objects, which
was incompatible with SLOB. This includes kfree_rcu() which had no
kmem_cache_free_rcu() counterpart yet and now it shouldn't be necessary
anymore.
Otherwise it's all straightforward removal. After this series, 'git grep
slob' or 'git grep SLOB' will have 3 remaining relevant hits in non-mm
code:
- tomoyo - patch submitted and carried there, doesn't need to wait for
this series
- skbuff - patch to cleanup now-unnecessary #ifdefs will be posted to
netdev after this is merged, as requested to avoid conflicts
- ftrace ring_buffer - patch to remove obsolete comment is carried there
The rest of 'git grep SLOB' hits are false positives, or intentional
(CREDITS, and mm/Kconfig SLUB_TINY description to help those that will
happen to migrate later).
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Trivial slab and slub fixes for 6.4. A comment fix, a structure
constification, and a config SLUB_DEBUG help text fix.
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Fix build errors on ARCH=alpha when CONFIG_MDA_CONSOLE=m.
This allows the ARCH macros to be the only ones defined.
In file included from ../drivers/video/console/mdacon.c:37:
../arch/alpha/include/asm/vga.h:17:40: error: expected identifier or '(' before 'volatile'
17 | static inline void scr_writew(u16 val, volatile u16 *addr)
| ^~~~~~~~
../include/linux/vt_buffer.h:24:34: note: in definition of macro 'scr_writew'
24 | #define scr_writew(val, addr) (*(addr) = (val))
| ^~~~
../include/linux/vt_buffer.h:24:40: error: expected ')' before '=' token
24 | #define scr_writew(val, addr) (*(addr) = (val))
| ^
../arch/alpha/include/asm/vga.h:17:20: note: in expansion of macro 'scr_writew'
17 | static inline void scr_writew(u16 val, volatile u16 *addr)
| ^~~~~~~~~~
../arch/alpha/include/asm/vga.h:25:29: error: expected identifier or '(' before 'volatile'
25 | static inline u16 scr_readw(volatile const u16 *addr)
| ^~~~~~~~
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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This will make it easier to free objects in situations when they can
come from either kmalloc() or kmem_cache_alloc(), and also allow
kfree_rcu() for freeing objects from kmem_cache_alloc().
For the SLAB and SLUB allocators this was always possible so with SLOB
gone, we can document it as supported.
Signed-off-by: Vlastimil Babka <[email protected]>
Reviewed-by: Mike Rapoport (IBM) <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Cc: Joel Fernandes <[email protected]>
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CONFIG_SLOB has been removed from Kconfig. Remove code and #ifdef's
specific to SLOB in the slab headers and common code.
Signed-off-by: Vlastimil Babka <[email protected]>
Reviewed-by: Hyeonggon Yoo <[email protected]>
Acked-by: Lorenzo Stoakes <[email protected]>
Acked-by: Mike Rapoport (IBM) <[email protected]>
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With SLOB removed we no longer need the PG_slob_free alias for
PG_private. Also update tools/mm/page-types.
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Hyeonggon Yoo <[email protected]>
Acked-by: Lorenzo Stoakes <[email protected]>
Acked-by: Mike Rapoport (IBM) <[email protected]>
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USB3.2 spec section 9.2.5.4 quotes that a function may signal that
it wants to exit from Function Suspend by sending a Function
Wake Notification to the host if it is enabled for function
remote wakeup. Add an api in composite layer that can be used
by the function drivers to support this feature. Also expose
a gadget op so that composite layer can trigger a wakeup request
to the UDC driver.
Reviewed-by: Thinh Nguyen <[email protected]>
Signed-off-by: Elson Roy Serrao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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The wakeup bit in the bmAttributes field indicates whether the device
is configured for remote wakeup. But this field should be allowed to
set only if the UDC supports such wakeup mechanism. So configure this
field based on UDC capability. Also inform the UDC whether the device
is configured for remote wakeup by implementing a gadget op.
Reviewed-by: Thinh Nguyen <[email protected]>
Signed-off-by: Elson Roy Serrao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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This patch adds sockmap support for vsock sockets. It is intended to be
usable by all transports, but only the virtio and loopback transports
are implemented.
SOCK_STREAM, SOCK_DGRAM, and SOCK_SEQPACKET are all supported.
Signed-off-by: Bobby Eshleman <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Stefano Garzarella <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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These new fields in QUERY_Q_COUNTER command allow us to access
another vport counters during the query command, which is specially
useful to query representor vports.
In addition also add the required caps to check if this capability
is actually supported.
Signed-off-by: Patrisious Haddad <[email protected]>
Reviewed-by: Michael Guralnik <[email protected]>
Link: https://lore.kernel.org/r/75c73a4a0e60f18c37b35a4a11ca2e2415e4a6f3.1679566038.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <[email protected]>
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A recent patch caused an unused-function warning in builds with
CONFIG_PM disabled, after the function became marked 'static':
drivers/usb/host/xhci-pci.c:91:13: error: 'xhci_msix_sync_irqs' defined but not used [-Werror=unused-function]
91 | static void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
| ^~~~~~~~~~~~~~~~~~~
This could be solved by adding another #ifdef, but as there is
a trend towards removing CONFIG_PM checks in favor of helper
macros, do the same conversion here and use pm_ptr() to get
either a function pointer or NULL but avoid the warning.
As the hidden functions reference some other symbols, make
sure those are visible at compile time, at the minimal cost of
a few extra bytes for 'struct usb_device'.
Fixes: 9abe15d55dcc ("xhci: Move xhci MSI sync function to to xhci-pci")
Signed-off-by: Arnd Bergmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux
Saeed Mahameed says:
====================
mlx5-updates-2023-03-20
mlx5 dynamic msix
This patch series adds support for dynamic msix vectors allocation in mlx5.
Eli Cohen Says:
================
The following series of patches modifies mlx5_core to work with the
dynamic MSIX API. Currently, mlx5_core allocates all the interrupt
vectors it needs and distributes them amongst the consumers. With the
introduction of dynamic MSIX support, which allows for allocation of
interrupts more than once, we now allocate vectors as we need them.
This allows other drivers running on top of mlx5_core to allocate
interrupt vectors for their own use. An example for this is mlx5_vdpa,
which uses these vectors to propagate interrupts directly from the
hardware to the vCPU [1].
As a preparation for using this series, a use after free issue is fixed
in lib/cpu_rmap.c and the allocator for rmap entries has been modified.
A complementary API for irq_cpu_rmap_add() has also been introduced.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux.git/patch/?id=0f2bf1fcae96a83b8c5581854713c9fc3407556e
================
* tag 'mlx5-updates-2023-03-20' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux:
net/mlx5: Provide external API for allocating vectors
net/mlx5: Use one completion vector if eth is disabled
net/mlx5: Refactor calculation of required completion vectors
net/mlx5: Move devlink registration before mlx5_load
net/mlx5: Use dynamic msix vectors allocation
net/mlx5: Refactor completion irq request/release code
net/mlx5: Improve naming of pci function vectors
net/mlx5: Use newer affinity descriptor
net/mlx5: Modify struct mlx5_irq to use struct msi_map
net/mlx5: Fix wrong comment
net/mlx5e: Coding style fix, add empty line
lib: cpu_rmap: Add irq_cpu_rmap_remove to complement irq_cpu_rmap_add
lib: cpu_rmap: Use allocator for rmap entries
lib: cpu_rmap: Avoid use after free on rmap->obj array entries
====================
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
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struct class should never be modified in a sysfs callback as there is
nothing in the structure to modify, and frankly, the structure is almost
never used in a sysfs callback, so mark it as constant to allow struct
class to be moved to read-only memory.
While we are touching all class sysfs callbacks also mark the attribute
as constant as it can not be modified. The bonding code still uses this
structure so it can not be removed from the function callbacks.
Cc: "David S. Miller" <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Bartosz Golaszewski <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Miquel Raynal <[email protected]>
Cc: Namjae Jeon <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Russ Weight <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steve French <[email protected]>
Cc: Vignesh Raghavendra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Luis Chamberlain <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pulling rcurefs from Peter for tglx's work.
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Jakub Kicinski <[email protected]>
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TRANSPARENT_HUGEPAGE_NEVER_DAX has nothing to do with DAX. It's set when
has_transparent_hugepage() returns false, checked in hugepage_vma_check()
and will disable THP completely if false. Rename it to
TRANSPARENT_HUGEPAGE_UNSUPPORTED to reflect its real purpose.
[[email protected]: fix comment, per David]
Link: https://lkml.kernel.org/r/ZBMzQW674oHQJV7F@x1n
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Peter Xu <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
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Patch series "make slab shrink lockless", v5.
This patch series aims to make slab shrink lockless.
1. Background
=============
On our servers, we often find the following system cpu hotspots:
52.22% [kernel] [k] down_read_trylock
19.60% [kernel] [k] up_read
8.86% [kernel] [k] shrink_slab
2.44% [kernel] [k] idr_find
1.25% [kernel] [k] count_shadow_nodes
1.18% [kernel] [k] shrink lruvec
0.71% [kernel] [k] mem_cgroup_iter
0.71% [kernel] [k] shrink_node
0.55% [kernel] [k] find_next_bit
And we used bpftrace to capture its calltrace as follows:
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
do_try_to_free_pages+232
try_to_free_pages+243
_alloc_pages_slowpath+771
_alloc_pages_nodemask+702
pagecache_get_page+255
filemap_fault+1361
ext4_filemap_fault+44
__do_fault+76
handle_mm_fault+3543
do_user_addr_fault+442
do_page_fault+48
page_fault+62
]: 1161690
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
balance_pgdat+690
kswapd+389
kthread+246
ret_from_fork+31
]: 8424884
@[
down_read_trylock+1
shrink_slab+128
shrink_node+371
do_try_to_free_pages+232
try_to_free_pages+243
__alloc_pages_slowpath+771
__alloc_pages_nodemask+702
__do_page_cache_readahead+244
filemap_fault+1674
ext4_filemap_fault+44
__do_fault+76
handle_mm_fault+3543
do_user_addr_fault+442
do_page_fault+48
page_fault+62
]: 20917631
We can see that down_read_trylock() of shrinker_rwsem is being called with
high frequency at that time. Because of the poor multicore scalability of
atomic operations, this can lead to a significant drop in IPC
(instructions per cycle).
And more, the shrinker_rwsem is a global read-write lock in shrinkers
subsystem, which protects most operations such as slab shrink,
registration and unregistration of shrinkers, etc. This can easily cause
problems in the following cases.
1) When the memory pressure is high and there are many filesystems
mounted or unmounted at the same time, slab shrink will be affected
(down_read_trylock() failed).
Such as the real workload mentioned by Kirill Tkhai:
```
One of the real workloads from my experience is start of an
overcommitted node containing many starting containers after node crash
(or many resuming containers after reboot for kernel update). In these
cases memory pressure is huge, and the node goes round in long reclaim.
```
2) If a shrinker is blocked (such as the case mentioned in [1]) and a
writer comes in (such as mount a fs), then this writer will be blocked
and cause all subsequent shrinker-related operations to be blocked.
[1]. https://lore.kernel.org/lkml/[email protected]/
All the above cases can be solved by replacing the shrinker_rwsem trylocks
with SRCU.
2. Survey
=========
Before doing the code implementation, I found that there were many similar
submissions in the community:
a. Davidlohr Bueso submitted a patch in 2015.
Subject: [PATCH -next v2] mm: srcu-ify shrinkers
Link: https://lore.kernel.org/all/[email protected]/
Result: It was finally merged into the linux-next branch,
but failed on arm allnoconfig (without CONFIG_SRCU)
b. Tetsuo Handa submitted a patchset in 2017.
Subject: [PATCH 1/2] mm,vmscan: Kill global shrinker lock.
Link: https://lore.kernel.org/lkml/1510609063-3327-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp/
Result: Finally chose to use the current simple way (break
when rwsem_is_contended()). And Christoph Hellwig suggested to
using SRCU, but SRCU was not unconditionally enabled at the
time.
c. Kirill Tkhai submitted a patchset in 2018.
Subject: [PATCH RFC 00/10] Introduce lockless shrink_slab()
Link: https://lore.kernel.org/lkml/153365347929.19074.12509495712735843805.stgit@localhost.localdomain/
Result: At that time, SRCU was not unconditionally enabled,
and there were some objections to enabling SRCU. Later,
because Kirill's focus was moved to other things, this patchset
was not continued to be updated.
d. Sultan Alsawaf submitted a patch in 2021.
Subject: [PATCH] mm: vmscan: Replace shrinker_rwsem trylocks with SRCU protection
Link: https://lore.kernel.org/lkml/[email protected]/
Result: Rejected because SRCU was not unconditionally enabled.
We can find that almost all these historical commits were abandoned
because SRCU was not unconditionally enabled. But now SRCU has been
unconditionally enable by Paul E. McKenney in 2023 [2], so it's time to
replace shrinker_rwsem trylocks with SRCU.
[2] https://lore.kernel.org/lkml/20230105003759.GA1769545@paulmck-ThinkPad-P17-Gen-1/
3. Reproduction and testing
===========================
We can reproduce the down_read_trylock() hotspot through the following script:
```
#!/bin/bash
DIR="/root/shrinker/memcg/mnt"
do_create()
{
mkdir -p /sys/fs/cgroup/memory/test
mkdir -p /sys/fs/cgroup/perf_event/test
echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
for i in `seq 0 $1`;
do
mkdir -p /sys/fs/cgroup/memory/test/$i;
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
mkdir -p $DIR/$i;
done
}
do_mount()
{
for i in `seq $1 $2`;
do
mount -t tmpfs $i $DIR/$i;
done
}
do_touch()
{
for i in `seq $1 $2`;
do
echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs;
dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 &
done
}
case "$1" in
touch)
do_touch $2 $3
;;
test)
do_create 4000
do_mount 0 4000
do_touch 0 3000
;;
*)
exit 1
;;
esac
```
Save the above script, then run test and touch commands. Then we can use
the following perf command to view hotspots:
perf top -U -F 999
1) Before applying this patchset:
32.31% [kernel] [k] down_read_trylock
19.40% [kernel] [k] pv_native_safe_halt
16.24% [kernel] [k] up_read
15.70% [kernel] [k] shrink_slab
4.69% [kernel] [k] _find_next_bit
2.62% [kernel] [k] shrink_node
1.78% [kernel] [k] shrink_lruvec
0.76% [kernel] [k] do_shrink_slab
2) After applying this patchset:
27.83% [kernel] [k] _find_next_bit
16.97% [kernel] [k] shrink_slab
15.82% [kernel] [k] pv_native_safe_halt
9.58% [kernel] [k] shrink_node
8.31% [kernel] [k] shrink_lruvec
5.64% [kernel] [k] do_shrink_slab
3.88% [kernel] [k] mem_cgroup_iter
At the same time, we use the following perf command to capture IPC
information:
perf stat -e cycles,instructions -G test -a --repeat 5 -- sleep 10
1) Before applying this patchset:
Performance counter stats for 'system wide' (5 runs):
454187219766 cycles test ( +- 1.84% )
78896433101 instructions test # 0.17 insn per cycle ( +- 0.44% )
10.0020430 +- 0.0000366 seconds time elapsed ( +- 0.00% )
2) After applying this patchset:
Performance counter stats for 'system wide' (5 runs):
841954709443 cycles test ( +- 15.80% ) (98.69%)
527258677936 instructions test # 0.63 insn per cycle ( +- 15.11% ) (98.68%)
10.01064 +- 0.00831 seconds time elapsed ( +- 0.08% )
We can see that IPC drops very seriously when calling down_read_trylock()
at high frequency. After using SRCU, the IPC is at a normal level.
This patch (of 8):
To prepare for the subsequent lockless memcg slab shrink, add a map_nr_max
field to struct shrinker_info to records its own real shrinker_nr_max.
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Qi Zheng <[email protected]>
Suggested-by: Kirill Tkhai <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Kirill Tkhai <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Cc: Christian König <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Qi Zheng <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Sultan Alsawaf <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
Code inspection reveals that PG_skip_kasan_poison is redundant with
kasantag, because the former is intended to be set iff the latter is the
match-all tag. It can also be observed that it's basically pointless to
poison pages which have kasantag=0, because any pages with this tag would
have been pointed to by pointers with match-all tags, so poisoning the
pages would have little to no effect in terms of bug detection.
Therefore, change the condition in should_skip_kasan_poison() to check
kasantag instead, and remove PG_skip_kasan_poison and associated flags.
Link: https://lkml.kernel.org/r/[email protected]
Link: https://linux-review.googlesource.com/id/I57f825f2eaeaf7e8389d6cf4597c8a5821359838
Signed-off-by: Peter Collingbourne <[email protected]>
Reviewed-by: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Evgenii Stepanov <[email protected]>
Cc: Vincenzo Frascino <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
io_mapping_map_atomic_wc() disables preemption and pagefaults for
historical reasons. The conversion to io_mapping_map_local_wc(), which
only disables migration, cannot be done wholesale because quite some call
sites need to be updated to accommodate with the changed semantics.
On PREEMPT_RT enabled kernels the io_mapping_map_atomic_wc() semantics are
problematic due to the implicit disabling of preemption which makes it
impossible to acquire 'sleeping' spinlocks within the mapped atomic
sections.
PREEMPT_RT replaces the preempt_disable() with a migrate_disable() for
more than a decade. It could be argued that this is a justification to do
this unconditionally, but PREEMPT_RT covers only a limited number of
architectures and it disables some functionality which limits the coverage
further.
Limit the replacement to PREEMPT_RT for now. This is also done
kmap_atomic().
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Reported-by: Richard Weinberger <[email protected]>
Link: https://lore.kernel.org/CAFLxGvw0WMxaMqYqJ5WgvVSbKHq2D2xcXTOgMCpgq9nDC-MWTQ@mail.gmail.com
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
In doing experimentations with shmem having the option to avoid swap
becomes a useful mechanism. One of the *raves* about brd over shmem is
you can avoid swap, but that's not really a good reason to use brd if we
can instead use shmem. Using brd has its own good reasons to exist, but
just because "tmpfs" doesn't let you do that is not a great reason to
avoid it if we can easily add support for it.
I don't add support for reconfiguring incompatible options, but if we
really wanted to we can add support for that.
To avoid swap we use mapping_set_unevictable() upon inode creation, and
put a WARN_ON_ONCE() stop-gap on writepages() for reclaim.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Luis Chamberlain <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Tested-by: Xin Hao <[email protected]>
Reviewed-by: Davidlohr Bueso <[email protected]>
Cc: Adam Manzanares <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Pankaj Raghav <[email protected]>
Cc: Yosry Ahmed <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
The last remaining user of folio_write_one through the write_one_page
wrapper is jfs, so move the functionality there and hard code the call to
metapage_writepage.
Note that the use of the pagecache by the JFS 'metapage' buffer cache is a
bit odd, and we could probably do without VM-level dirty tracking at all,
but that's a change for another time.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Dave Kleikamp <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Evgeniy Dushistov <[email protected]>
Cc: Gang He <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jan Kara via Ocfs2-devel <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Joseph Qi <[email protected]>
Cc: Jun Piao <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
The knob for cgroup v1 memory controller: memory.swappiness is not
protected by any locking so it can be modified while it is used. This is
not an actual problem because races are unlikely. But it is better to use
[READ|WRITE]_ONCE to prevent compiler from doing anything funky.
The access of memcg->swappiness and vm_swappiness is lockless, so both of
them can be concurrently set at the same time as we are trying to read
them. All occurrences of memcg->swappiness and vm_swappiness are updated
with [READ|WRITE]_ONCE.
[[email protected]: v3]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yue Zhao <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Shakeel Butt <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Tang Yizhou <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
s390 can do more fine-grained handling of spurious TLB protection faults,
when there also is the PTE pointer available.
Therefore, pass on the PTE pointer to flush_tlb_fix_spurious_fault() as an
additional parameter.
This will add no functional change to other architectures, but those with
private flush_tlb_fix_spurious_fault() implementations need to be made
aware of the new parameter.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Gerald Schaefer <[email protected]>
Reviewed-by: Alexander Gordeev <[email protected]>
Acked-by: Catalin Marinas <[email protected]> [arm64]
Acked-by: Michael Ellerman <[email protected]> [powerpc]
Acked-by: David Hildenbrand <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
All the callers of cgroup_throttle_swaprate() are converted to
folio_throttle_swaprate(), so make __cgroup_throttle_swaprate() to take a
folio, and rename it to __folio_throttle_swaprate(), also rename gfp_mask
to gfp and drop redundant extern keyword. finally, drop unused
cgroup_throttle_swaprate().
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
Instead of changing the page's tag solely in order to obtain a pointer
with a match-all tag and then changing it back again, just convert the
pointer that we get from kmap_atomic() into one with a match-all tag
before passing it to clear_page().
On a certain microarchitecture, this has been observed to cause a
measurable improvement in microbenchmark performance, presumably as a
result of being able to avoid the atomic operations on the page tag.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Peter Collingbourne <[email protected]>
Link: https://linux-review.googlesource.com/id/I0249822cc29097ca7a04ad48e8eb14871f80e711
Reviewed-by: Andrey Konovalov <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Evgenii Stepanov <[email protected]>
Cc: Peter Collingbourne <[email protected]>
Cc: Vincenzo Frascino <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
%pGp format is used to display 'flags' field of a struct page. However,
some page flags (i.e. PG_buddy, see page-flags.h for more details) are
stored in page_type field. To display human-readable output of page_type,
introduce %pGt format.
It is important to note the meaning of bits are different in page_type.
if page_type is 0xffffffff, no flags are set. Setting PG_buddy
(0x00000080) flag results in a page_type of 0xffffff7f. Clearing a bit
actually means setting a flag. Bits in page_type are inverted when
displaying type names.
Only values for which page_type_has_type() returns true are considered as
page_type, to avoid confusion with mapcount values. if it returns false,
only raw values are displayed and not page type names.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Hyeonggon Yoo <[email protected]>
Reviewed-by: Petr Mladek <[email protected]> [vsprintf part]
Cc: Andy Shevchenko <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: John Ogness <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt (Google) <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
Add CONFIG_MMU_TLB_REFCOUNT which enables refcounting of the lazy tlb mm
when it is context switched. This can be disabled by architectures that
don't require this refcounting if they clean up lazy tlb mms when the last
refcount is dropped. Currently this is always enabled, so the patch
introduces no functional change.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Nicholas Piggin <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|
|
Add explicit _lazy_tlb annotated functions for lazy tlb mm refcounting.
This makes the lazy tlb mm references more obvious, and allows the
refcounting scheme to be modified in later changes. There is no
functional change with this patch.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Nicholas Piggin <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
|