| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
Quite often, devices do not need dma_sync operations on x86_64 at least.
Indeed, when dev_is_dma_coherent(dev) is true and
dev_use_swiotlb(dev) is false, iommu_dma_sync_single_for_cpu()
and friends do nothing.
However, indirectly calling them when CONFIG_RETPOLINE=y consumes about
10% of cycles on a cpu receiving packets from softirq at ~100Gbit rate.
Even if/when CONFIG_RETPOLINE is not set, there is a cost of about 3%.
Add dev->need_dma_sync boolean and turn it off during the device
initialization (dma_set_mask()) depending on the setup:
dev_is_dma_coherent() for the direct DMA, !(sync_single_for_device ||
sync_single_for_cpu) or the new dma_map_ops flag, %DMA_F_CAN_SKIP_SYNC,
advertised for non-NULL DMA ops.
Then later, if/when swiotlb is used for the first time, the flag
is reset back to on, from swiotlb_tbl_map_single().
On iavf, the UDP trafficgen with XDP_DROP in skb mode test shows
+3-5% increase for direct DMA.
Suggested-by: Christoph Hellwig <hch@lst.de> # direct DMA shortcut
Co-developed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
Some platforms do have DMA, but DMA there is always direct and coherent.
Currently, even on such platforms DMA sync operations are compiled and
called.
Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when
either sync operations are needed or there is DMA ops or swiotlb
or DMA debug is enabled. Compile global dma_sync_*() and dma_need_sync()
only when it's set, otherwise provide empty inline stubs.
The change allows for future optimizations of DMA sync calls depending
on runtime conditions.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
iommu_dma_map_page() allocates swiotlb memory as a bounce buffer when an
untrusted device wants to map only part of the memory in an granule. The
goal is to disallow the untrusted device having DMA access to unrelated
kernel data that may be sharing the granule. To meet this goal, the
bounce buffer itself is zeroed, and any additional swiotlb memory up to
alloc_size after the bounce buffer end (i.e., "post-padding") is also
zeroed.
However, as of commit 901c7280ca0d ("Reinstate some of "swiotlb: rework
"fix info leak with DMA_FROM_DEVICE"""), swiotlb_tbl_map_single() always
initializes the contents of the bounce buffer to the original memory.
Zeroing the bounce buffer is redundant and probably wrong per the
discussion in that commit. Only the post-padding needs to be zeroed.
Also, when the DMA min_align_mask is non-zero, the allocated bounce
buffer space may not start on a granule boundary. The swiotlb memory
from the granule boundary to the start of the allocated bounce buffer
might belong to some unrelated bounce buffer. So as described in the
"second issue" in [1], it can't be zeroed to protect against untrusted
devices. But as of commit af133562d5af ("swiotlb: extend buffer
pre-padding to alloc_align_mask if necessary"), swiotlb_tbl_map_single()
allocates pre-padding slots when necessary to meet min_align_mask
requirements, making it possible to zero the pre-padding area as well.
Finally, iommu_dma_map_page() uses the swiotlb for untrusted devices
and also for certain kmalloc() memory. Current code does the zeroing
for both cases, but it is needed only for the untrusted device case.
Fix all of this by updating iommu_dma_map_page() to zero both the
pre-padding and post-padding areas, but not the actual bounce buffer.
Do this only in the case where the bounce buffer is used because
of an untrusted device.
[1] https://lore.kernel.org/all/20210929023300.335969-1-stevensd@google.com/
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Petr Tesarik <petr@tesarici.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
Currently swiotlb_tbl_map_single() takes alloc_align_mask and
alloc_size arguments to specify an swiotlb allocation that is larger
than mapping_size. This larger allocation is used solely by
iommu_dma_map_single() to handle untrusted devices that should not have
DMA visibility to memory pages that are partially used for unrelated
kernel data.
Having two arguments to specify the allocation is redundant. While
alloc_align_mask naturally specifies the alignment of the starting
address of the allocation, it can also implicitly specify the size
by rounding up the mapping_size to that alignment.
Additionally, the current approach has an edge case bug.
iommu_dma_map_page() already does the rounding up to compute the
alloc_size argument. But swiotlb_tbl_map_single() then calculates the
alignment offset based on the DMA min_align_mask, and adds that offset to
alloc_size. If the offset is non-zero, the addition may result in a value
that is larger than the max the swiotlb can allocate. If the rounding up
is done _after_ the alignment offset is added to the mapping_size (and
the original mapping_size conforms to the value returned by
swiotlb_max_mapping_size), then the max that the swiotlb can allocate
will not be exceeded.
In view of these issues, simplify the swiotlb_tbl_map_single() interface
by removing the alloc_size argument. Most call sites pass the same value
for mapping_size and alloc_size, and they pass alloc_align_mask as zero.
Just remove the redundant argument from these callers, as they will see
no functional change. For iommu_dma_map_page() also remove the alloc_size
argument, and have swiotlb_tbl_map_single() compute the alloc_size by
rounding up mapping_size after adding the offset based on min_align_mask.
This has the side effect of fixing the edge case bug but with no other
functional change.
Also add a sanity test on the alloc_align_mask. While IOMMU code
currently ensures the granule is not larger than PAGE_SIZE, if that
guarantee were to be removed in the future, the downstream effect on the
swiotlb might go unnoticed until strange allocation failures occurred.
Tested on an ARM64 system with 16K page size and some kernel test-only
hackery to allow modifying the DMA min_align_mask and the granule size
that becomes the alloc_align_mask. Tested these combinations with a
variety of original memory addresses and sizes, including those that
reproduce the edge case bug:
* 4K granule and 0 min_align_mask
* 4K granule and 0xFFF min_align_mask (4K - 1)
* 16K granule and 0xFFF min_align_mask
* 64K granule and 0xFFF min_align_mask
* 64K granule and 0x3FFF min_align_mask (16K - 1)
With the changes, all combinations pass.
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Petr Tesarik <petr@tesarici.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
Cleanup some deprecated uses of strncpy() and strcpy() [1].
There doesn't seem to be any bugs with the current code but the
readability of this code could benefit from a quick makeover while
removing some deprecated stuff as a benefit.
The most interesting replacement made in this patch involves
concatenating "ttyS" with a digit-led user-supplied string. Instead of
doing two distinct string copies with carefully managed offsets and
lengths, let's use the more robust and self-explanatory scnprintf().
scnprintf will 1) respect the bounds of @buf, 2) null-terminate @buf, 3)
do the concatenation. This allows us to drop the manual NUL-byte assignment.
Also, since isdigit() is used about a dozen lines after the open-coded
version we'll replace it for uniformity's sake.
All the strcpy() --> strscpy() replacements are trivial as the source
strings are literals and much smaller than the destination size. No
behavioral change here.
Use the new 2-argument version of strscpy() introduced in Commit
e6584c3964f2f ("string: Allow 2-argument strscpy()"). However, to make
this work fully (since the size must be known at compile time), also
update the extern-qualified declaration to have the proper size
information.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90 [2]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [3]
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240429-strncpy-kernel-printk-printk-c-v1-1-4da7926d7b69@google.com
[pmladek@suse.com: Removed obsolete brackets and added empty lines.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
|
|
Currently the documentation for line names allows to use %u inside
the alternative name. This is broken in character device approach
from day 1 and being in use solely in sysfs.
Character device interface has a line number as a part of its address,
so the users better rely on it. Hence remove the misleading documentation.
On top of that, there are no in-kernel users (out of 6, if I'm correct)
for such names and moreover if one exists it won't help in distinguishing
lines with the same naming as '%u' will also be in them and we will get
a warning in gpiochip_set_desc_names() for such cases.
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240505141420.627398-1-andy.shevchenko@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
|
|
intel-gpio for v6.10-1
* New driver for vGPIO controller on Intel Granite Rapids-D
* Update ACPI GPIO library to unify the IRQ code path
* Better GPIO IRQ line labeling for ACPI
* Switched Intel SCH driver to use "mapped" I/O accessors
The following is an automated git shortlog grouped by driver:
Add Intel Granite Rapids-D vGPIO driver:
- Add Intel Granite Rapids-D vGPIO driver
crystalcove:
- Use -ENOTSUPP consistently
gpiolib:
- acpi: Set label for IRQ only lines
- acpi: Add fwnode name to the GPIO interrupt label
- acpi: Pass con_id instead of property into acpi_dev_gpio_irq_get_by()
- acpi: Move acpi_can_fallback_to_crs() out of __acpi_find_gpio()
- acpi: Simplify error handling in __acpi_find_gpio()
- acpi: Extract __acpi_find_gpio() helper
- acpi: Check for errors first in acpi_find_gpio()
- acpi: Remove never true check in acpi_get_gpiod_by_index()
sch:
- Utilise temporary variable for struct device
- Switch to memory mapped IO accessors
wcove:
- Use -ENOTSUPP consistently
|
|
On x86_64 and allmodconfig, this shrinks the size of 'struct regmap_config'
from 328 to 312 bytes.
This is usually a win, because this structure is used as a static global
variable.
When moving the kerneldoc fields, I've tried to keep the layout as
consistent as possible, which is not really easy!
Before:
/* size: 328, cachelines: 6, members: 55 */
/* sum members: 296, holes: 6, sum holes: 25 */
/* padding: 7 */
/* last cacheline: 8 bytes */
After:
/* size: 312, cachelines: 5, members: 55 */
/* sum members: 296, holes: 5, sum holes: 16 */
/* last cacheline: 56 bytes */
For the records, this is also widely used:
$git grep static.*regmap_config | wc -l
1327
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/5e039cd8fe415dd7ab3169948c08a5311db9fb9a.1715024007.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>
|
|
This reverts commit 07ed11afb68d94eadd4ffc082b97c2331307c5ea.
Stephen Rostedt reports:
"I went to run my tests on my VMs and the tests hung on boot up.
Unfortunately, the most I ever got out was:
[ 93.607888] Testing event system initcall: OK
[ 93.667730] Running tests on all trace events:
[ 93.669757] Testing all events: OK
[ 95.631064] ------------[ cut here ]------------
Timed out after 60 seconds"
and further debugging points to a possible circular locking dependency
between the console_owner locking and the worker pool locking.
Reverting the commit allows Steve's VM to boot to completion again.
[ This may obviously result in the "[TTM] Buffer eviction failed"
messages again, which was the reason for that original revert. But at
this point this seems preferable to a non-booting system... ]
Reported-and-bisected-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20240502081641.457aa25f@gandalf.local.home/
Acked-by: Maxime Ripard <mripard@kernel.org>
Cc: Alex Constantino <dreaming.about.electric.sheep@gmail.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Timo Lindfors <timo.lindfors@iki.fi>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Pull slab fixes from Vlastimil Babka:
- Fix for cleanup infrastructure (Dan Carpenter)
This makes the __free(kfree) cleanup hooks not crash on error
pointers.
- SLUB fix for freepointer checking (Nicolas Bouchinet)
This fixes a recently introduced bug that manifests when
init_on_free, CONFIG_SLAB_FREELIST_HARDENED and consistency checks
(slub_debug=F) are all enabled, and results in false-positive
freepointer corrupt reports for caches that store freepointer outside
of the object area.
* tag 'slab-for-6.9-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab: make __free(kfree) accept error pointers
mm/slub: avoid zeroing outside-object freepointer for single free
|
|
CONFIG_BASE_SMALL is currently a type int but is only used as a boolean.
So, change its type to bool and adapt all usages:
CONFIG_BASE_SMALL == 0 becomes !IS_ENABLED(CONFIG_BASE_SMALL) and
CONFIG_BASE_SMALL != 0 becomes IS_ENABLED(CONFIG_BASE_SMALL).
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Link: https://lore.kernel.org/r/20240505080343.1471198-3-yoann.congal@smile.fr
Signed-off-by: Petr Mladek <pmladek@suse.com>
|
|
svc_find_listener will return the transport instance pointer for the
endpoint accepting connections/peer traffic from the specified transport
class and matching sockaddr.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
|
|
Add svc_xprt_create_from_sa utility routine and refactor
svc_xprt_create() codebase in order to introduce the capability to
create a svc port from socket address.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
|
|
This adds basic infrastructure for handing GET_DIR_DELEGATION calls from
clients, including the decoders and encoders. For now, it always just
returns NFS4_OK + GDD4_UNAVAIL.
Eventually clients may start sending this operation, and it's better if
we can return GDD4_UNAVAIL instead of having to abort the whole compound.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
|
|
|
|
All EV4 machines are already gone, and the remaining EV5 based machines
all support the slightly more modern EV56 generation as well.
Debian only supports EV56 and later.
Drop both of these and build kernels optimized for EV56 and higher
when the "generic" options is selected, tuning for an out-of-order
EV6 pipeline, same as Debian userspace.
Since this was the only supported architecture without 8-bit and
16-bit stores, common kernel code no longer has to worry about
aligning struct members, and existing workarounds from the block
and tty layers can be removed.
The alpha memory management code no longer needs an abstraction
for the differences between EV4 and EV5+.
Link: https://lists.debian.org/debian-alpha/2023/05/msg00009.html
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
|
|
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/ZgIrOuR3JI/jzqoH@neat
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
|
|
Merge series from David Lechner <dlechner@baylibre.com>:
In the IIO subsystem, we noticed a pattern in many drivers where we need
to get, enable and get the voltage of a supply that provides a reference
voltage. In these cases, we only need the voltage and not a handle to
the regulator. Another common pattern is for chips to have an internal
reference voltage that is used when an external reference is not
available. There are also a few drivers outside of IIO that do the same.
So we would like to propose a new regulator consumer API to handle these
specific cases to avoid repeating the same boilerplate code in multiple
drivers.
As an example of how these functions are used, I have included a few
patches to consumer drivers. But to avoid a giant patch bomb, I have
omitted the iio/adc and iio/dac patches I have prepared from this
series. I will send those separately but these will add 36 more users
of devm_regulator_get_enable_read_voltage() in addition to the 6 here.
In total, this will eliminate nearly 1000 lines of similar code and will
simplify writing and reviewing new drivers in the future.
|
|
Make trylock_page return bool to align the return values of folio_trylock
function and it also corresponds to its comment.
Link: https://lkml.kernel.org/r/20240428014711.11169-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Define yet another DAMOS filter type, YOUNG. Like anon and memcg, the
type of filter will be applied to each page in the memory region, and see
if the page is accessed since the last check. Based on the 'matching'
parameter, the page is filtered out or in.
Note that this commit is adding only the type definition. The
implementation should be made by DAMON operations sets. A commit for the
implementation on 'paddr' DAMON operations set will follow.
Link: https://lkml.kernel.org/r/20240426195247.100306-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Tested-by: Honggyu Kim <honggyu.kim@sk.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Combine the three boolean arguments into one flags argument for
readability.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats
of bdi.
Following domain hierarchy is tested:
global domain (320G)
/ \
cgroup domain1(10G) cgroup domain2(10G)
| |
bdi wb1 wb2
/* per wb writeback info of bdi is collected */
cat wb_stats
WbCgIno: 1
WbWriteback: 0 kB
WbReclaimable: 0 kB
WbDirtyThresh: 0 kB
WbDirtied: 0 kB
WbWritten: 0 kB
WbWriteBandwidth: 102400 kBps
b_dirty: 0
b_io: 0
b_more_io: 0
b_dirty_time: 0
state: 1
WbCgIno: 4091
WbWriteback: 1792 kB
WbReclaimable: 820512 kB
WbDirtyThresh: 6004692 kB
WbDirtied: 1820448 kB
WbWritten: 999488 kB
WbWriteBandwidth: 169020 kBps
b_dirty: 0
b_io: 0
b_more_io: 1
b_dirty_time: 0
state: 5
WbCgIno: 4131
WbWriteback: 1120 kB
WbReclaimable: 820064 kB
WbDirtyThresh: 6004728 kB
WbDirtied: 1822688 kB
WbWritten: 1002400 kB
WbWriteBandwidth: 153520 kBps
b_dirty: 0
b_io: 0
b_more_io: 1
b_dirty_time: 0
state: 5
[shikemeng@huaweicloud.com: fix build problems]
Link: https://lkml.kernel.org/r/20240423034643.141219-4-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20240423034643.141219-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers now use folio_*_referenced() so we can remove the
PageReferenced family of functions.
Link: https://lkml.kernel.org/r/20240424191914.361554-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
With all callers converted to folios, we can act directly on
folio->_refcount.
Link: https://lkml.kernel.org/r/20240424191914.361554-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers have a folio so we can remove this use of
page_ref_sub_return().
Link: https://lkml.kernel.org/r/20240424191914.361554-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
It only has one caller; convert that caller to use
put_devmap_managed_page_refs() instead.
Link: https://lkml.kernel.org/r/20240424191914.361554-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "More folio compat code removal".
More code removal with bonus kernel-doc addition.
This patch (of 7):
All callers have now been converted to filemap_alloc_folio().
Link: https://lkml.kernel.org/r/20240424191914.361554-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240424191914.361554-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We've already calculated it, so pass it in instead of recalculating it in
collect_procs_ksm().
Link: https://lkml.kernel.org/r/20240412193510.2356957-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The page is only used to get the mapping, so the folio will do just as
well. Both callers already have a folio available, so this saves a call
to compound_head().
Link: https://lkml.kernel.org/r/20240412193510.2356957-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Removes two calls to compound_head(). Move the prototype to internal.h;
we definitely don't want code outside mm using it.
Link: https://lkml.kernel.org/r/20240412193510.2356957-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The only user of this function calls page_address_in_vma() immediately
after page_mapped_in_vma() calculates it and uses it to return true/false.
Return the address instead, allowing memory-failure to skip the call to
page_address_in_vma().
Link: https://lkml.kernel.org/r/20240412193510.2356957-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update header inclusions to follow IWYU (Include What You Use)
principle.
Link: https://lkml.kernel.org/r/20240423142204.2408923-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "xarray: Clean up xarray.h".
Main portion of this change is to get rid of kernel.h included into other
globally available headers. This decreases a dependency hell degree. The
first patch makes it possible to avoid math.h to be included as bitops.h
is implied by bitmap.h.
This patch (of 2):
Use BITS_PER_LONGS() instead of open coded variant.
Link: https://lkml.kernel.org/r/20240423142204.2408923-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
mod_memcg_lruvec_state() is never called from outside of memcontrol.c and
with always irq disabled. So, replace it with the irq disabled version
and add an assert that irq is disabled in the caller.
Similarly mod_objcg_state() is not called from outside of memcontrol.c, so
simply make it static and change it's name to __mod_objcg_state().
Link: https://lkml.kernel.org/r/20240420232505.2768428-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Make PageUptodate return bool to align the return values of
folio_test_uptodate function
Link: https://lkml.kernel.org/r/20240422032725.41452-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ruihan Li <lrh2000@pku.edu.cn>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free",
v10.
This patchset adds support for lazyfreeing multi-size THP (mTHP) without
needing to first split the large folio via split_folio(). However, we
still need to split a large folio that is not fully mapped within the
target range.
If a large folio is locked or shared, or if we fail to split it, we just
leave it in place and advance to the next PTE in the range. But note that
the behavior is changed; previously, any failure of this sort would cause
the entire operation to give up. As large folios become more common,
sticking to the old way could result in wasted opportunities.
Performance Testing
===================
On an Intel I5 CPU, lazyfreeing a 1GiB VMA backed by PTE-mapped folios of
the same size results in the following runtimes for madvise(MADV_FREE) in
seconds (shorter is better):
Folio Size | Old | New | Change
------------------------------------------
4KiB | 0.590251 | 0.590259 | 0%
16KiB | 2.990447 | 0.185655 | -94%
32KiB | 2.547831 | 0.104870 | -95%
64KiB | 2.457796 | 0.052812 | -97%
128KiB | 2.281034 | 0.032777 | -99%
256KiB | 2.230387 | 0.017496 | -99%
512KiB | 2.189106 | 0.010781 | -99%
1024KiB | 2.183949 | 0.007753 | -99%
2048KiB | 0.002799 | 0.002804 | 0%
This patch (of 4):
This commit introduces clear_young_dirty_ptes() to replace mkold_ptes().
By doing so, we can use the same function for both use cases
(madvise_pageout and madvise_free), and it also provides the flexibility
to only clear the dirty flag in the future if needed.
Link: https://lkml.kernel.org/r/20240418134435.6092-1-ioworker0@gmail.com
Link: https://lkml.kernel.org/r/20240418134435.6092-2-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Suggested-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Jeff Xie <xiehuan09@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Distinguish these functions from brelse() and __brelse().
Link: https://lkml.kernel.org/r/20240416031754.4076917-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Move the documentation for __brelse() to brelse(), format it as kernel-doc
and update it from talking about pages to folios.
Link: https://lkml.kernel.org/r/20240416031754.4076917-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The extra indentation confused the kernel-doc parser, so remove it. Fix
some other wording while I'm here, and advise the user they need to call
brelse() on this buffer.
__bread_gfp() isn't used directly by filesystems, but the other wrappers
for it don't have documentation, so document it accordingly.
Link: https://lkml.kernel.org/r/20240416031754.4076917-5-willy@infradead.org
Co-developed-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This helps to display the fragmentation situation of the swapfile, knowing
the proportion of how much we haven't split large folios. So far, we only
support non-split swapout for anon memory, with the possibility of
expanding to shmem in the future. So, we add the "anon" prefix to the
counter names.
Link: https://lkml.kernel.org/r/20240412114858.407208-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: add per-order mTHP alloc and swpout counters", v6.
The patchset introduces a framework to facilitate mTHP counters, starting
with the allocation and swap-out counters. Currently, only four new nodes
are appended to the stats directory for each mTHP size.
/sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats
anon_fault_alloc
anon_fault_fallback
anon_fault_fallback_charge
anon_swpout
anon_swpout_fallback
These nodes are crucial for us to monitor the fragmentation levels of both
the buddy system and the swap partitions. In the future, we may consider
adding additional nodes for further insights.
This patch (of 4):
Profiling a system blindly with mTHP has become challenging due to the
lack of visibility into its operations. Presenting the success rate of
mTHP allocations appears to be pressing need.
Recently, I've been experiencing significant difficulty debugging
performance improvements and regressions without these figures. It's
crucial for us to understand the true effectiveness of mTHP in real-world
scenarios, especially in systems with fragmented memory.
This patch establishes the framework for per-order mTHP counters. It
begins by introducing the anon_fault_alloc and anon_fault_fallback
counters. Additionally, to maintain consistency with
thp_fault_fallback_charge in /proc/vmstat, this patch also tracks
anon_fault_fallback_charge when mem_cgroup_charge fails for mTHP.
Incorporating additional counters should now be straightforward as well.
Link: https://lkml.kernel.org/r/20240412114858.407208-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240412114858.407208-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
dissolve_free_huge_pages() only uses folios internally, rename it to
dissolve_free_hugetlb_folios() and change the comments which reference it.
[akpm@linux-foundation.org: remove unneeded `extern']
Link: https://lkml.kernel.org/r/20240412182139.120871-2-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Allows us to rename dissolve_free_huge_pages() to
dissolve_free_hugetlb_folio(). Convert one caller to pass in a folio
directly and use page_folio() to convert the caller in mm/memory-failure.
[sidhartha.kumar@oracle.com: remove unneeded `extern']
Link: https://lkml.kernel.org/r/71760ed4-e80d-493a-95ea-2545414b1aba@oracle.com
[sidhartha.kumar@oracle.com: v2]
Link: https://lkml.kernel.org/r/20240412182139.120871-1-sidhartha.kumar@oracle.com
Link: https://lkml.kernel.org/r/20240411164756.261178-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We already handle it properly for large folios. Let's also return "0" for
small typed folios, like page_mapcount() currently would.
Consequently, folio_mapcount() will never return negative values for typed
folios, but may return negative values for underflows.
[david@redhat.com: make folio_mapcount() slightly more efficient]
Link: https://lkml.kernel.org/r/c30fcda1-ed87-46f5-8297-cdedbddac009@redhat.com
Link: https://lkml.kernel.org/r/20240409192301.907377-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We can now read the mapcount of large folios very efficiently. Use it to
improve our handling of partially-mappable folios, falling back to making
a guess only in case the folio is not "obviously mapped shared".
We can now better detect partially-mappable folios where the first page is
not mapped as "mapped shared", reducing "false negatives"; but false
negatives are still possible.
While at it, fixup a wrong comment (false positive vs. false negative)
for KSM folios.
Link: https://lkml.kernel.org/r/20240409192301.907377-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's track the mapcount of large folios in a single value. The mapcount
of a large folio currently corresponds to the sum of the entire mapcount
and all page mapcounts.
This sum is what we actually want to know in folio_mapcount() and it is
also sufficient for implementing folio_mapped().
With PTE-mapped THP becoming more important and more widely used, we want
to avoid looping over all pages of a folio just to obtain the mapcount of
large folios. The comment "In the common case, avoid the loop when no
pages mapped by PTE" in folio_total_mapcount() does no longer hold for
mTHP that are always mapped by PTE.
Further, we are planning on using folio_mapcount() more frequently, and
might even want to remove page mapcounts for large folios in some kernel
configs. Therefore, allow for reading the mapcount of large folios
efficiently and atomically without looping over any pages.
Maintain the mapcount also for hugetlb pages for simplicity. Use the new
mapcount to implement folio_mapcount() and folio_mapped(). Make
page_mapped() simply call folio_mapped(). We can now get rid of
folio_large_is_mapped().
_nr_pages_mapped is now only used in rmap code and for debugging purposes.
Keep folio_nr_pages_mapped() around, but document that its use should be
limited to rmap internals and debugging purposes.
This change implies one additional atomic add/sub whenever
mapping/unmapping (parts of) a large folio.
As we now batch RMAP operations for PTE-mapped THP during fork(), during
unmap/zap, and when PTE-remapping a PMD-mapped THP, and we adjust the
large mapcount for a PTE batch only once, the added overhead in the common
case is small. Only when unmapping individual pages of a large folio
(e.g., during COW), the overhead might be bigger in comparison, but it's
essentially one additional atomic operation.
Note that before the new mapcount would overflow, already our refcount
would overflow: each mapping requires a folio reference. Extend the
focumentation of folio_mapcount().
Link: https://lkml.kernel.org/r/20240409192301.907377-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's add a fast-path for small folios to all relevant rmap functions.
Note that only RMAP_LEVEL_PTE applies.
This is a preparation for tracking the mapcount of large folios in a
single value.
Link: https://lkml.kernel.org/r/20240409192301.907377-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
As we grow the code, the compiler might make stupid decisions and
unnecessarily degrade fork() performance. Let's make sure to always
inline functions that operate on a single PTE so the compiler will always
optimize out the loop and avoid a function call.
This is a preparation for maintining a total mapcount for large folios.
Link: https://lkml.kernel.org/r/20240409192301.907377-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: mapcount for large folios + page_mapcount() cleanups".
This series tracks the mapcount of large folios in a single value, so it
can be read efficiently and atomically, just like the mapcount of small
folios.
folio_mapcount() is then used in a couple more places, most notably to
reduce false negatives in folio_likely_mapped_shared(), and many users of
page_mapcount() are cleaned up (that's maybe why you got CCed on the full
series, sorry sh+xtensa folks! :) ).
The remaining s390x user and one KSM user of page_mapcount() are getting
removed separately on the list right now. I have patches to handle the
other KSM one, the khugepaged one and the kpagecount one; as they are not
as "obvious", I will send them out separately in the future. Once that is
all in place, I'm planning on moving page_mapcount() into
fs/proc/task_mmu.c, the remaining user for the time being (and we can
discuss at LSF/MM details on that :) ).
I proposed the mapcount for large folios (previously called total
mapcount) originally in part of [1] and I later included it in [2] where
it is a requirement. In the meantime, I changed the patch a bit so I
dropped all RB's. During the discussion of [1], Peter Xu correctly raised
that this additional tracking might affect the performance when PMD->PTE
remapping THPs. In the meantime. I addressed that by batching RMAP
operations during fork(), unmap/zap and when PMD->PTE remapping THPs.
Running some of my micro-benchmarks [3] (fork,munmap,cow-byte,remap) on 1
GiB of memory backed by folios with the same order, I observe the
following on an Intel(R) Xeon(R) Silver 4210R CPU @ 2.40GHz tuned for
reproducible results as much as possible:
Standard deviation is mostly < 1%, except for order-9, where it's < 2% for
fork() and munmap().
(1) Small folios are not affected (< 1%) in all 4 microbenchmarks.
(2) Order-4 folios are not affected (< 1%) in all 4 microbenchmarks. A bit
weird comapred to the other orders ...
(3) PMD->PTE remapping of order-9 THPs is not affected (< 1%)
(4) COW-byte (COWing a single page by writing a single byte) is not
affected for any order (< 1 %). The page copy_fault overhead dominates
everything.
(5) fork() is mostly not affected (< 1%), except order-2, where we have
a slowdown of ~4%. Already for order-3 folios, we're down to a slowdown
of < 1%.
(6) munmap() sees a slowdown by < 3% for some orders (order-5,
order-6, order-9), but less for others (< 1% for order-4 and order-8,
< 2% for order-2, order-3, order-7).
Especially the fork() and munmap() benchmark are sensitive to each added
instruction and other system noise, so I suspect some of the change and
observed weirdness (order-4) is due to code layout changes and other
factors, but not really due to the added atomics.
So in the common case where we can batch, the added atomics don't really
make a big difference, especially in light of the recent improvements for
large folios that we recently gained due to batching. Surprisingly, for
some cases where we cannot batch (e.g., COW), the added atomics don't seem
to matter, because other overhead dominates.
My fork and munmap micro-benchmarks don't cover cases where we cannot
batch-process bigger parts of large folios. As this is not the common
case, I'm not worrying about that right now.
Future work is batching RMAP operations during swapout and folio
migration.
[1] https://lore.kernel.org/all/20230809083256.699513-1-david@redhat.com/
[2] https://lore.kernel.org/all/20231124132626.235350-1-david@redhat.com/
[3] https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/pte-mapped-folio-benchmarks.c?ref_type=heads
This patch (of 18):
Commit 53277bcf126d ("mm: support page_mapcount() on page_has_type()
pages") made it impossible to detect mapcount underflows by treating any
negative raw mapcount value as a mapcount of 0.
We perform such underflow checks in zap_present_folio_ptes() and
zap_huge_pmd(), which would currently no longer trigger.
Let's check against PAGE_MAPCOUNT_RESERVE instead by using
page_type_has_type(), like page_has_type() would, so we can still catch
some underflows.
[david@redhat.com: make page_mapcount() slighly more efficient]
Link: https://lkml.kernel.org/r/1af4fd61-7926-47c8-be45-833c0dbec08b@redhat.com
Link: https://lkml.kernel.org/r/20240409192301.907377-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240409192301.907377-2-david@redhat.com
Fixes: 53277bcf126d ("mm: support page_mapcount() on page_has_type() pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Richard Chang <richardycc@google.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
... and centralize the VM_IO/VM_PFNMAP sanity check in there. We'll
now also perform these sanity checks for direct follow_pte()
invocations.
For generic_access_phys(), we might now check multiple times: nothing to
worry about, really.
Link: https://lkml.kernel.org/r/20240410155527.474777-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Sean Christopherson <seanjc@google.com> [KVM]
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Fei Li <fei1.li@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Yonghua Huang <yonghua.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
Alexander Lobakin
Michael Kelley
Justin Stitt
Andy Shevchenko
Bartosz Golaszewski
Christophe JAILLET
Linus Torvalds
Yoann Congal
Jeff Layton
Lorenzo Bianconi
Rafael J. Wysocki
Arnd Bergmann
Gustavo A. R. Silva
Mark Brown
Hao Ge
SeongJae Park
Matthew Wilcox
Kemeng Shi
Andy Shevchenko
Shakeel Butt
Lance Yang
Barry Song
Sidhartha Kumar
David Hildenbrand