When allocating a new pool at runtime, reduce the number of slabs so
that the allocation order is at most MAX_ORDER. This avoids a kernel
warning in __alloc_pages().
The warning is relatively benign, because the pool size is subsequently
reduced when allocation fails, but it is silly to start with a request
that is known to fail, especially since this is the default behavior if
the kernel is built with CONFIG_SWIOTLB_DYNAMIC=y and booted without any
swiotlb= parameter.
Reported-by: Ben Greear <greearb@candelatech.com>
Closes: https://lore.kernel.org/netdev/4f173dd2-324a-0240-ff8d-abf5c191be18@candelatech.com/
Fixes: 1aaa736815 ("swiotlb: allocate a new memory pool when existing pools are full")
Signed-off-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
When CONFIG_SWIOTLB_DYNAMIC=y, devices which do not use the software IO TLB
can avoid swiotlb lookup. A flag is added by commit 1395706a14 ("swiotlb:
search the software IO TLB only if the device makes use of it"), the flag
is correctly set, but it is then never checked. Add the actual check here.
Note that this code is an alternative to the default pool check, not an
additional check, because:
1. swiotlb_find_pool() also searches the default pool;
2. if dma_uses_io_tlb is false, the default swiotlb pool is not used.
Tested in a KVM guest against a QEMU RAM-backed SATA disk over virtio and
*not* using software IO TLB, this patch increases IOPS by approx 2% for
4-way parallel I/O.
The write memory barrier in swiotlb_dyn_alloc() is not needed, because a
newly allocated pool must always be observed by swiotlb_find_slots() before
an address from that pool is passed to is_swiotlb_buffer().
Correctness was verified using the following litmus test:
C swiotlb-new-pool
(*
* Result: Never
*
* Check that a newly allocated pool is always visible when the
* corresponding swiotlb buffer is visible.
*)
{
mem_pools = default;
}
P0(int **mem_pools, int *pool)
{
/* add_mem_pool() */
WRITE_ONCE(*pool, 999);
rcu_assign_pointer(*mem_pools, pool);
}
P1(int **mem_pools, int *flag, int *buf)
{
/* swiotlb_find_slots() */
int *r0;
int r1;
rcu_read_lock();
r0 = READ_ONCE(*mem_pools);
r1 = READ_ONCE(*r0);
rcu_read_unlock();
if (r1) {
WRITE_ONCE(*flag, 1);
smp_mb();
}
/* device driver (presumed) */
WRITE_ONCE(*buf, r1);
}
P2(int **mem_pools, int *flag, int *buf)
{
/* device driver (presumed) */
int r0 = READ_ONCE(*buf);
/* is_swiotlb_buffer() */
int r1;
int *r2;
int r3;
smp_rmb();
r1 = READ_ONCE(*flag);
if (r1) {
/* swiotlb_find_pool() */
rcu_read_lock();
r2 = READ_ONCE(*mem_pools);
r3 = READ_ONCE(*r2);
rcu_read_unlock();
}
}
exists (2:r0<>0 /\ 2:r3=0) (* Not found. *)
Fixes: 1395706a14 ("swiotlb: search the software IO TLB only if the device makes use of it")
Reported-by: Jonathan Corbet <corbet@lwn.net>
Closes: https://lore.kernel.org/linux-iommu/87a5uz3ob8.fsf@meer.lwn.net/
Signed-off-by: Petr Tesarik <petr@tesarici.cz>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Commit 8ac0406335 ("swiotlb: reduce the number of areas to match
actual memory pool size") calculated the reduced number of areas in
swiotlb_init_remap() but didn't actually use the value. Replace usage of
default_nareas accordingly.
Fixes: 8ac0406335 ("swiotlb: reduce the number of areas to match actual memory pool size")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This reverts commit 3fa6456ebe.
The Commit broke the CMA region creation through DT on arm64,
as showed below logs with "memblock=debug":
[ 0.000000] memblock_phys_alloc_range: 41943040 bytes align=0x200000
from=0x0000000000000000 max_addr=0x00000000ffffffff
early_init_dt_alloc_reserved_memory_arch+0x34/0xa0
[ 0.000000] memblock_reserve: [0x00000000fd600000-0x00000000ffdfffff]
memblock_alloc_range_nid+0xc0/0x19c
[ 0.000000] Reserved memory: overlap with other memblock reserved region
>From call flow, region we defined in DT was always reserved before entering
into rmem_cma_setup. Also, rmem_cma_setup has one routine cma_init_reserved_mem
to ensure the region was reserved. Checking the region not reserved here seems
not correct.
early_init_fdt_scan_reserved_mem:
fdt_scan_reserved_mem
__reserved_mem_reserve_reg
early_init_dt_reserve_memory
memblock_reserve(using “reg” prop case)
fdt_init_reserved_mem
__reserved_mem_alloc_size
*early_init_dt_alloc_reserved_memory_arch*
memblock_reserve(dynamic alloc case)
__reserved_mem_init_node
rmem_cma_setup(region overlap check here should always fail)
Example DT can be used to reproduce issue:
dump_mem: mem_dump_region {
compatible = "shared-dma-pool";
alloc-ranges = <0x0 0x00000000 0x0 0xffffffff>;
reusable;
size = <0 0x2800000>;
};
Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Move the #endif a line so that free_page label is only seen by the
compile pass when actually used.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chunhui He <hchunhui@mail.ustc.edu.cn>
Reviewed-by: Robin Murphy <roin.murphy@arm.com>
It makes no sense to expose CONFIG_DMA_NUMA_CMA if CONFIG_NUMA is not
enabled, and random config options shouldn't be default unless there
is a good reason. Replace the default NUMA with a depends on to fix both
issues.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <roin.murphy@arm.com>
Use a simple logical shift and increment to calculate the number of slots
taken by the DMA segment boundary.
At least GCC-13 is not able to optimize the expression, producing this
horrible assembly code on x86:
cmpq $-1, %rcx
je .L364
addq $2048, %rcx
shrq $11, %rcx
movq %rcx, %r13
.L331:
// rest of the function here...
// after function epilogue and return:
.L364:
movabsq $9007199254740992, %r13
jmp .L331
After the optimization, the code looks more reasonable:
shrq $11, %r11
leaq 1(%r11), %rbx
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Move the comment down in front of the loop that actually sets the list
member of struct io_tlb_slot to zero.
Fixes: 26a7e09478 ("swiotlb: refactor swiotlb_tbl_map_single")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Skip searching the software IO TLB if a device has never used it, making
sure these devices are not affected by the introduction of multiple IO TLB
memory pools.
Additional memory barrier is required to ensure that the new value of the
flag is visible to other CPUs after mapping a new bounce buffer. For
efficiency, the flag check should be inlined, and then the memory barrier
must be moved to is_swiotlb_buffer(). However, it can replace the existing
barrier in swiotlb_find_pool(), because all callers use is_swiotlb_buffer()
first to verify that the buffer address belongs to the software IO TLB.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
When swiotlb_find_slots() cannot find suitable slots, schedule the
allocation of a new memory pool. It is not possible to allocate the pool
immediately, because this code may run in interrupt context, which is not
suitable for large memory allocations. This means that the memory pool will
be available too late for the currently requested mapping, but the stress
on the software IO TLB allocator is likely to continue, and subsequent
allocations will benefit from the additional pool eventually.
Keep all memory pools for an allocator in an RCU list to avoid locking on
the read side. For modifications, add a new spinlock to struct io_tlb_mem.
The spinlock also protects updates to the total number of slabs (nslabs in
struct io_tlb_mem), but not reads of the value. Readers may therefore
encounter a stale value, but this is not an issue:
- swiotlb_tbl_map_single() and is_swiotlb_active() only check for non-zero
value. This is ensured by the existence of the default memory pool,
allocated at boot.
- The exact value is used only for non-critical purposes (debugfs, kernel
messages).
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The value returned by default_swiotlb_limit() should be constant, because
it is used to decide whether DMA can be used. To allow allocating memory
pools on the fly, use the maximum possible physical address rather than the
highest address used by the default pool.
For swiotlb_init_remap(), this is either an arch-specific limit used by
memblock_alloc_low(), or the highest directly mapped physical address if
the initialization flags include SWIOTLB_ANY. For swiotlb_init_late(), the
highest address is determined by the GFP flags.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Try to allocate a transient memory pool if no suitable slots can be found
and the respective SWIOTLB is allowed to grow. The transient pool is just
enough big for this one bounce buffer. It is inserted into a per-device
list of transient memory pools, and it is freed again when the bounce
buffer is unmapped.
Transient memory pools are kept in an RCU list. A memory barrier is
required after adding a new entry, because any address within a transient
buffer must be immediately recognized as belonging to the SWIOTLB, even if
it is passed to another CPU.
Deletion does not require any synchronization beyond RCU ordering
guarantees. After a buffer is unmapped, its physical addresses may no
longer be passed to the DMA API, so the memory range of the corresponding
stale entry in the RCU list never matches. If the memory range gets
allocated again, then it happens only after a RCU quiescent state.
Since bounce buffers can now be allocated from different pools, add a
parameter to swiotlb_alloc_pool() to let the caller know which memory pool
is used. Add swiotlb_find_pool() to find the memory pool corresponding to
an address. This function is now also used by is_swiotlb_buffer(), because
a simple boundary check is no longer sufficient.
The logic in swiotlb_alloc_tlb() is taken from __dma_direct_alloc_pages(),
simplified and enhanced to use coherent memory pools if needed.
Note that this is not the most efficient way to provide a bounce buffer,
but when a DMA buffer can't be mapped, something may (and will) actually
break. At that point it is better to make an allocation, even if it may be
an expensive operation.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a config option (CONFIG_SWIOTLB_DYNAMIC) to enable or disable dynamic
allocation of additional bounce buffers.
If this option is set, mark the default SWIOTLB as able to grow and
restricted DMA pools as unable.
However, if the address of the default memory pool is explicitly queried,
make the default SWIOTLB also unable to grow. This is currently used to set
up PCI BAR movable regions on some Octeon MIPS boards which may not be able
to use a SWIOTLB pool elsewhere in physical memory. See octeon_pci_setup()
for more details.
If a remap function is specified, it must be also called on any dynamically
allocated pools, but there are some issues:
- The remap function may block, so it should not be called from an atomic
context.
- There is no corresponding unremap() function if the memory pool is
freed.
- The only in-tree implementation (xen_swiotlb_fixup) requires that the
number of slots in the memory pool is a multiple of SWIOTLB_SEGSIZE.
Keep it simple for now and disable growing the SWIOTLB if a remap function
was specified.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Carve out memory pool specific fields from struct io_tlb_mem. The original
struct now contains shared data for the whole allocator, while the new
struct io_tlb_pool contains data that is specific to one memory pool of
(potentially) many.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add some kernel-doc comments and move the existing documentation of struct
io_tlb_slot to its correct location. The latter was forgotten in commit
942a8186eb ("swiotlb: move struct io_tlb_slot to swiotlb.c").
Use the opportunity to give swiotlb_do_find_slots() a more descriptive name
and make it clear how it differs from swiotlb_find_slots().
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
SWIOTLB implementation details should not be exposed to the rest of the
kernel. This will allow to make changes to the implementation without
modifying non-swiotlb code.
To avoid breaking existing users, provide helper functions for the few
required fields.
As a bonus, using a helper function to initialize struct device allows to
get rid of an #ifdef in driver core.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
If swiotlb is allocated, immediately return 0, so callers do not have to
check io_tlb_default_mem.nslabs explicitly.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
In the process of parsing the DTS, check whether the memory region
specified by the DTS CMA node area overlaps with the kernel text
memory space reserved by memblock before calling
early_init_fdt_scan_reserved_mem.
Signed-off-by: Binglei Wang <l3b2w1@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The kernel parameter 'cma_pernuma=' only supports reserving the same
size of CMA area for each node. We need to reserve different sizes of
CMA area for specified nodes if these devices belong to different nodes.
Adding another kernel parameter 'numa_cma=' to reserve CMA area for
the specified node. If we want to use one of these parameters, we need to
enable DMA_NUMA_CMA.
At the same time, print the node id in cma_declare_contiguous_nid() if
CONFIG_NUMA is enabled.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Christoph Hellwig <hch@lst.de>
In the commit b7176c261c ("dma-contiguous: provide the ability to
reserve per-numa CMA"), Barry adds DMA_PERNUMA_CMA for ARM64.
But this feature is architecture independent, so support per-numa CMA
for all architectures, and enable it by default if NUMA.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This function has a __weak definition and an override that is only used on
freescale powerpc chips. The powerpc definition however does not see the
declaration that is in a .c file:
arch/powerpc/kernel/dma-mask.c:7:6: error: no previous prototype for 'arch_dma_set_mask' [-Werror=missing-prototypes]
Move it into the linux/dma-map-ops.h header where the other arch_dma_* functions
are declared.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Drivers have no business looking at dma-mapping or swiotlb internals.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
- swiotlb area sizing fixes (Petr Tesarik)
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Merge tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
- swiotlb area sizing fixes (Petr Tesarik)
* tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: reduce the number of areas to match actual memory pool size
swiotlb: always set the number of areas before allocating the pool
- swiotlb cleanups (Petr Tesarik)
- use kvmalloc_array (gaoxu)
- a small step towards removing is_swiotlb_active (Christoph Hellwig)
- fix a Kconfig typo Sui Jingfeng)
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Merge tag 'dma-mapping-6.5-2023-06-28' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping updates from Christoph Hellwig:
- swiotlb cleanups (Petr Tesarik)
- use kvmalloc_array (gaoxu)
- a small step towards removing is_swiotlb_active (Christoph Hellwig)
- fix a Kconfig typo Sui Jingfeng)
* tag 'dma-mapping-6.5-2023-06-28' of git://git.infradead.org/users/hch/dma-mapping:
drm/nouveau: stop using is_swiotlb_active
swiotlb: use the atomic counter of total used slabs if available
swiotlb: remove unused field "used" from struct io_tlb_mem
dma-remap: use kvmalloc_array/kvfree for larger dma memory remap
dma-mapping: fix a Kconfig typo
Although the desired size of the SWIOTLB memory pool is increased in
swiotlb_adjust_nareas() to match the number of areas, the actual allocation
may be smaller, which may require reducing the number of areas.
For example, Xen uses swiotlb_init_late(), which in turn uses the page
allocator. On x86, page size is 4 KiB and MAX_ORDER is 10 (1024 pages),
resulting in a maximum memory pool size of 4 MiB. This corresponds to 2048
slots of 2 KiB each. The minimum area size is 128 (IO_TLB_SEGSIZE),
allowing at most 2048 / 128 = 16 areas.
If num_possible_cpus() is greater than the maximum number of areas, areas
are smaller than IO_TLB_SEGSIZE and contiguous groups of free slots will
span multiple areas. When allocating and freeing slots, only one area will
be properly locked, causing race conditions on the unlocked slots and
ultimately data corruption, kernel hangs and crashes.
Fixes: 20347fca71 ("swiotlb: split up the global swiotlb lock")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The number of areas defaults to the number of possible CPUs. However, the
total number of slots may have to be increased after adjusting the number
of areas. Consequently, the number of areas must be determined before
allocating the memory pool. This is even explained with a comment in
swiotlb_init_remap(), but swiotlb_init_late() adjusts the number of areas
after slots are already allocated. The areas may end up being smaller than
IO_TLB_SEGSIZE, which breaks per-area locking.
While fixing swiotlb_init_late(), move all relevant comments before the
definition of swiotlb_adjust_nareas() and convert them to kernel-doc.
Fixes: 20347fca71 ("swiotlb: split up the global swiotlb lock")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
For direct DMA, if the size is small enough to have originated from a
kmalloc() cache below ARCH_DMA_MINALIGN, check its alignment against
dma_get_cache_alignment() and bounce if necessary. For larger sizes, it
is the responsibility of the DMA API caller to ensure proper alignment.
At this point, the kmalloc() caches are properly aligned but this will
change in a subsequent patch.
Architectures can opt in by selecting DMA_BOUNCE_UNALIGNED_KMALLOC.
Link: https://lkml.kernel.org/r/20230612153201.554742-15-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
sg_is_dma_bus_address() is inconsistent with the naming pattern of its
corresponding setters and its own kerneldoc, so take the majority vote and
rename it sg_dma_is_bus_address() (and fix up the missing underscores in
the kerneldoc too). This gives us a nice clear pattern where SG DMA flags
are SG_DMA_<NAME>, and the helpers for acting on them are
sg_dma_<action>_<name>().
Link: https://lkml.kernel.org/r/20230612153201.554742-14-catalin.marinas@arm.com
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://lore.kernel.org/r/fa2eca2862c7ffc41b50337abffb2dfd2864d3ea.1685036694.git.robin.murphy@arm.com
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The DMA flags field will be useful for users beyond PCI P2P, so upgrade to
its own dedicated config option.
[catalin.marinas@arm.com: use #ifdef CONFIG_NEED_SG_DMA_FLAGS in scatterlist.h]
[catalin.marinas@arm.com: update PCI_P2PDMA dma_flags comment in scatterlist.h]
Link: https://lkml.kernel.org/r/20230612153201.554742-13-catalin.marinas@arm.com
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If DEBUG_FS is enabled, the cost of keeping an exact number of total
used slabs is already paid. In this case, there is no reason to use an
inexact number for statistics and kernel messages.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
If dma_direct_alloc() alloc memory in size of 64MB, the inner function
dma_common_contiguous_remap() will allocate 128KB memory by invoking
the function kmalloc_array(). and the kmalloc_array seems to fail to try to
allocate 128KB mem.
Call trace:
[14977.928623] qcrosvm: page allocation failure: order:5, mode:0x40cc0
[14977.928638] dump_backtrace.cfi_jt+0x0/0x8
[14977.928647] dump_stack_lvl+0x80/0xb8
[14977.928652] warn_alloc+0x164/0x200
[14977.928657] __alloc_pages_slowpath+0x9f0/0xb4c
[14977.928660] __alloc_pages+0x21c/0x39c
[14977.928662] kmalloc_order+0x48/0x108
[14977.928666] kmalloc_order_trace+0x34/0x154
[14977.928668] __kmalloc+0x548/0x7e4
[14977.928673] dma_direct_alloc+0x11c/0x4f8
[14977.928678] dma_alloc_attrs+0xf4/0x138
[14977.928680] gh_vm_ioctl_set_fw_name+0x3c4/0x610 [gunyah]
[14977.928698] gh_vm_ioctl+0x90/0x14c [gunyah]
[14977.928705] __arm64_sys_ioctl+0x184/0x210
work around by doing kvmalloc_array instead.
Signed-off-by: Gao Xu <gaoxu2@hihonor.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
- fix a PageHighMem check in dma-coherent initialization (Doug Berger)
- clean up the coherency defaul initialiation (Jiaxun Yang)
- add cacheline to user/kernel dma-debug space dump messages
(Desnes Nunes, Geert Uytterhoeve)
- swiotlb statistics improvements (Michael Kelley)
- misc cleanups (Petr Tesarik)
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Merge tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping updates from Christoph Hellwig:
- fix a PageHighMem check in dma-coherent initialization (Doug Berger)
- clean up the coherency defaul initialiation (Jiaxun Yang)
- add cacheline to user/kernel dma-debug space dump messages (Desnes
Nunes, Geert Uytterhoeve)
- swiotlb statistics improvements (Michael Kelley)
- misc cleanups (Petr Tesarik)
* tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: Omit total_used and used_hiwater if !CONFIG_DEBUG_FS
swiotlb: track and report io_tlb_used high water marks in debugfs
swiotlb: fix debugfs reporting of reserved memory pools
swiotlb: relocate PageHighMem test away from rmem_swiotlb_setup
of: address: always use dma_default_coherent for default coherency
dma-mapping: provide CONFIG_ARCH_DMA_DEFAULT_COHERENT
dma-mapping: provide a fallback dma_default_coherent
dma-debug: Use %pa to format phys_addr_t
dma-debug: add cacheline to user/kernel space dump messages
dma-debug: small dma_debug_entry's comment and variable name updates
dma-direct: cleanup parameters to dma_direct_optimal_gfp_mask
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page().
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather
than exclusive, and has fixed a bunch of errors which were caused by its
unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
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Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics
flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...
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Merge tag 'hyperv-next-signed-20230424' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:
- PCI passthrough for Hyper-V confidential VMs (Michael Kelley)
- Hyper-V VTL mode support (Saurabh Sengar)
- Move panic report initialization code earlier (Long Li)
- Various improvements and bug fixes (Dexuan Cui and Michael Kelley)
* tag 'hyperv-next-signed-20230424' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (22 commits)
PCI: hv: Replace retarget_msi_interrupt_params with hyperv_pcpu_input_arg
Drivers: hv: move panic report code from vmbus to hv early init code
x86/hyperv: VTL support for Hyper-V
Drivers: hv: Kconfig: Add HYPERV_VTL_MODE
x86/hyperv: Make hv_get_nmi_reason public
x86/hyperv: Add VTL specific structs and hypercalls
x86/init: Make get/set_rtc_noop() public
x86/hyperv: Exclude lazy TLB mode CPUs from enlightened TLB flushes
x86/hyperv: Add callback filter to cpumask_to_vpset()
Drivers: hv: vmbus: Remove the per-CPU post_msg_page
clocksource: hyper-v: make sure Invariant-TSC is used if it is available
PCI: hv: Enable PCI pass-thru devices in Confidential VMs
Drivers: hv: Don't remap addresses that are above shared_gpa_boundary
hv_netvsc: Remove second mapping of send and recv buffers
Drivers: hv: vmbus: Remove second way of mapping ring buffers
Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages
swiotlb: Remove bounce buffer remapping for Hyper-V
Driver: VMBus: Add Devicetree support
dt-bindings: bus: Add Hyper-V VMBus
Drivers: hv: vmbus: Convert acpi_device to more generic platform_device
...
The summary of the changes for this pull requests is:
* Song Liu's new struct module_memory replacement
* Nick Alcock's MODULE_LICENSE() removal for non-modules
* My cleanups and enhancements to reduce the areas where we vmalloc
module memory for duplicates, and the respective debug code which
proves the remaining vmalloc pressure comes from userspace.
Most of the changes have been in linux-next for quite some time except
the minor fixes I made to check if a module was already loaded
prior to allocating the final module memory with vmalloc and the
respective debug code it introduces to help clarify the issue. Although
the functional change is small it is rather safe as it can only *help*
reduce vmalloc space for duplicates and is confirmed to fix a bootup
issue with over 400 CPUs with KASAN enabled. I don't expect stable
kernels to pick up that fix as the cleanups would have also had to have
been picked up. Folks on larger CPU systems with modules will want to
just upgrade if vmalloc space has been an issue on bootup.
Given the size of this request, here's some more elaborate details
on this pull request.
The functional change change in this pull request is the very first
patch from Song Liu which replaces the struct module_layout with a new
struct module memory. The old data structure tried to put together all
types of supported module memory types in one data structure, the new
one abstracts the differences in memory types in a module to allow each
one to provide their own set of details. This paves the way in the
future so we can deal with them in a cleaner way. If you look at changes
they also provide a nice cleanup of how we handle these different memory
areas in a module. This change has been in linux-next since before the
merge window opened for v6.3 so to provide more than a full kernel cycle
of testing. It's a good thing as quite a bit of fixes have been found
for it.
Jason Baron then made dynamic debug a first class citizen module user by
using module notifier callbacks to allocate / remove module specific
dynamic debug information.
Nick Alcock has done quite a bit of work cross-tree to remove module
license tags from things which cannot possibly be module at my request
so to:
a) help him with his longer term tooling goals which require a
deterministic evaluation if a piece a symbol code could ever be
part of a module or not. But quite recently it is has been made
clear that tooling is not the only one that would benefit.
Disambiguating symbols also helps efforts such as live patching,
kprobes and BPF, but for other reasons and R&D on this area
is active with no clear solution in sight.
b) help us inch closer to the now generally accepted long term goal
of automating all the MODULE_LICENSE() tags from SPDX license tags
In so far as a) is concerned, although module license tags are a no-op
for non-modules, tools which would want create a mapping of possible
modules can only rely on the module license tag after the commit
8b41fc4454 ("kbuild: create modules.builtin without Makefile.modbuiltin
or tristate.conf"). Nick has been working on this *for years* and
AFAICT I was the only one to suggest two alternatives to this approach
for tooling. The complexity in one of my suggested approaches lies in
that we'd need a possible-obj-m and a could-be-module which would check
if the object being built is part of any kconfig build which could ever
lead to it being part of a module, and if so define a new define
-DPOSSIBLE_MODULE [0]. A more obvious yet theoretical approach I've
suggested would be to have a tristate in kconfig imply the same new
-DPOSSIBLE_MODULE as well but that means getting kconfig symbol names
mapping to modules always, and I don't think that's the case today. I am
not aware of Nick or anyone exploring either of these options. Quite
recently Josh Poimboeuf has pointed out that live patching, kprobes and
BPF would benefit from resolving some part of the disambiguation as
well but for other reasons. The function granularity KASLR (fgkaslr)
patches were mentioned but Joe Lawrence has clarified this effort has
been dropped with no clear solution in sight [1].
In the meantime removing module license tags from code which could never
be modules is welcomed for both objectives mentioned above. Some
developers have also welcomed these changes as it has helped clarify
when a module was never possible and they forgot to clean this up,
and so you'll see quite a bit of Nick's patches in other pull
requests for this merge window. I just picked up the stragglers after
rc3. LWN has good coverage on the motivation behind this work [2] and
the typical cross-tree issues he ran into along the way. The only
concrete blocker issue he ran into was that we should not remove the
MODULE_LICENSE() tags from files which have no SPDX tags yet, even if
they can never be modules. Nick ended up giving up on his efforts due
to having to do this vetting and backlash he ran into from folks who
really did *not understand* the core of the issue nor were providing
any alternative / guidance. I've gone through his changes and dropped
the patches which dropped the module license tags where an SPDX
license tag was missing, it only consisted of 11 drivers. To see
if a pull request deals with a file which lacks SPDX tags you
can just use:
./scripts/spdxcheck.py -f \
$(git diff --name-only commid-id | xargs echo)
You'll see a core module file in this pull request for the above,
but that's not related to his changes. WE just need to add the SPDX
license tag for the kernel/module/kmod.c file in the future but
it demonstrates the effectiveness of the script.
Most of Nick's changes were spread out through different trees,
and I just picked up the slack after rc3 for the last kernel was out.
Those changes have been in linux-next for over two weeks.
The cleanups, debug code I added and final fix I added for modules
were motivated by David Hildenbrand's report of boot failing on
a systems with over 400 CPUs when KASAN was enabled due to running
out of virtual memory space. Although the functional change only
consists of 3 lines in the patch "module: avoid allocation if module is
already present and ready", proving that this was the best we can
do on the modules side took quite a bit of effort and new debug code.
The initial cleanups I did on the modules side of things has been
in linux-next since around rc3 of the last kernel, the actual final
fix for and debug code however have only been in linux-next for about a
week or so but I think it is worth getting that code in for this merge
window as it does help fix / prove / evaluate the issues reported
with larger number of CPUs. Userspace is not yet fixed as it is taking
a bit of time for folks to understand the crux of the issue and find a
proper resolution. Worst come to worst, I have a kludge-of-concept [3]
of how to make kernel_read*() calls for modules unique / converge them,
but I'm currently inclined to just see if userspace can fix this
instead.
[0] https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/
[1] https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com
[2] https://lwn.net/Articles/927569/
[3] https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org
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Merge tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull module updates from Luis Chamberlain:
"The summary of the changes for this pull requests is:
- Song Liu's new struct module_memory replacement
- Nick Alcock's MODULE_LICENSE() removal for non-modules
- My cleanups and enhancements to reduce the areas where we vmalloc
module memory for duplicates, and the respective debug code which
proves the remaining vmalloc pressure comes from userspace.
Most of the changes have been in linux-next for quite some time except
the minor fixes I made to check if a module was already loaded prior
to allocating the final module memory with vmalloc and the respective
debug code it introduces to help clarify the issue. Although the
functional change is small it is rather safe as it can only *help*
reduce vmalloc space for duplicates and is confirmed to fix a bootup
issue with over 400 CPUs with KASAN enabled. I don't expect stable
kernels to pick up that fix as the cleanups would have also had to
have been picked up. Folks on larger CPU systems with modules will
want to just upgrade if vmalloc space has been an issue on bootup.
Given the size of this request, here's some more elaborate details:
The functional change change in this pull request is the very first
patch from Song Liu which replaces the 'struct module_layout' with a
new 'struct module_memory'. The old data structure tried to put
together all types of supported module memory types in one data
structure, the new one abstracts the differences in memory types in a
module to allow each one to provide their own set of details. This
paves the way in the future so we can deal with them in a cleaner way.
If you look at changes they also provide a nice cleanup of how we
handle these different memory areas in a module. This change has been
in linux-next since before the merge window opened for v6.3 so to
provide more than a full kernel cycle of testing. It's a good thing as
quite a bit of fixes have been found for it.
Jason Baron then made dynamic debug a first class citizen module user
by using module notifier callbacks to allocate / remove module
specific dynamic debug information.
Nick Alcock has done quite a bit of work cross-tree to remove module
license tags from things which cannot possibly be module at my request
so to:
a) help him with his longer term tooling goals which require a
deterministic evaluation if a piece a symbol code could ever be
part of a module or not. But quite recently it is has been made
clear that tooling is not the only one that would benefit.
Disambiguating symbols also helps efforts such as live patching,
kprobes and BPF, but for other reasons and R&D on this area is
active with no clear solution in sight.
b) help us inch closer to the now generally accepted long term goal
of automating all the MODULE_LICENSE() tags from SPDX license tags
In so far as a) is concerned, although module license tags are a no-op
for non-modules, tools which would want create a mapping of possible
modules can only rely on the module license tag after the commit
8b41fc4454 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf").
Nick has been working on this *for years* and AFAICT I was the only
one to suggest two alternatives to this approach for tooling. The
complexity in one of my suggested approaches lies in that we'd need a
possible-obj-m and a could-be-module which would check if the object
being built is part of any kconfig build which could ever lead to it
being part of a module, and if so define a new define
-DPOSSIBLE_MODULE [0].
A more obvious yet theoretical approach I've suggested would be to
have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
well but that means getting kconfig symbol names mapping to modules
always, and I don't think that's the case today. I am not aware of
Nick or anyone exploring either of these options. Quite recently Josh
Poimboeuf has pointed out that live patching, kprobes and BPF would
benefit from resolving some part of the disambiguation as well but for
other reasons. The function granularity KASLR (fgkaslr) patches were
mentioned but Joe Lawrence has clarified this effort has been dropped
with no clear solution in sight [1].
In the meantime removing module license tags from code which could
never be modules is welcomed for both objectives mentioned above. Some
developers have also welcomed these changes as it has helped clarify
when a module was never possible and they forgot to clean this up, and
so you'll see quite a bit of Nick's patches in other pull requests for
this merge window. I just picked up the stragglers after rc3. LWN has
good coverage on the motivation behind this work [2] and the typical
cross-tree issues he ran into along the way. The only concrete blocker
issue he ran into was that we should not remove the MODULE_LICENSE()
tags from files which have no SPDX tags yet, even if they can never be
modules. Nick ended up giving up on his efforts due to having to do
this vetting and backlash he ran into from folks who really did *not
understand* the core of the issue nor were providing any alternative /
guidance. I've gone through his changes and dropped the patches which
dropped the module license tags where an SPDX license tag was missing,
it only consisted of 11 drivers. To see if a pull request deals with a
file which lacks SPDX tags you can just use:
./scripts/spdxcheck.py -f \
$(git diff --name-only commid-id | xargs echo)
You'll see a core module file in this pull request for the above, but
that's not related to his changes. WE just need to add the SPDX
license tag for the kernel/module/kmod.c file in the future but it
demonstrates the effectiveness of the script.
Most of Nick's changes were spread out through different trees, and I
just picked up the slack after rc3 for the last kernel was out. Those
changes have been in linux-next for over two weeks.
The cleanups, debug code I added and final fix I added for modules
were motivated by David Hildenbrand's report of boot failing on a
systems with over 400 CPUs when KASAN was enabled due to running out
of virtual memory space. Although the functional change only consists
of 3 lines in the patch "module: avoid allocation if module is already
present and ready", proving that this was the best we can do on the
modules side took quite a bit of effort and new debug code.
The initial cleanups I did on the modules side of things has been in
linux-next since around rc3 of the last kernel, the actual final fix
for and debug code however have only been in linux-next for about a
week or so but I think it is worth getting that code in for this merge
window as it does help fix / prove / evaluate the issues reported with
larger number of CPUs. Userspace is not yet fixed as it is taking a
bit of time for folks to understand the crux of the issue and find a
proper resolution. Worst come to worst, I have a kludge-of-concept [3]
of how to make kernel_read*() calls for modules unique / converge
them, but I'm currently inclined to just see if userspace can fix this
instead"
Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]
* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
module: add debugging auto-load duplicate module support
module: stats: fix invalid_mod_bytes typo
module: remove use of uninitialized variable len
module: fix building stats for 32-bit targets
module: stats: include uapi/linux/module.h
module: avoid allocation if module is already present and ready
module: add debug stats to help identify memory pressure
module: extract patient module check into helper
modules/kmod: replace implementation with a semaphore
Change DEFINE_SEMAPHORE() to take a number argument
module: fix kmemleak annotations for non init ELF sections
module: Ignore L0 and rename is_arm_mapping_symbol()
module: Move is_arm_mapping_symbol() to module_symbol.h
module: Sync code of is_arm_mapping_symbol()
scripts/gdb: use mem instead of core_layout to get the module address
interconnect: remove module-related code
interconnect: remove MODULE_LICENSE in non-modules
zswap: remove MODULE_LICENSE in non-modules
zpool: remove MODULE_LICENSE in non-modules
x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
...
The tracking of used_hiwater adds an atomic operation to the hot
path. This is acceptable only when debugging the kernel. To make
sure that the fields can never be used by mistake, do not even
include them in struct io_tlb_mem if CONFIG_DEBUG_FS is not set.
The build fails after doing that. To fix it, it is necessary to
remove all code specific to debugfs and instead provide a stub
implementation of swiotlb_create_debugfs_files(). As a bonus, this
change allows to remove one __maybe_unused attribute.
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
With changes to how Hyper-V guest VMs flip memory between private
(encrypted) and shared (decrypted), creating a second kernel virtual
mapping for shared memory is no longer necessary. Everything needed
for the transition to shared is handled by set_memory_decrypted().
As such, remove swiotlb_unencrypted_base and the associated
code.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/1679838727-87310-8-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
swiotlb currently reports the total number of slabs and the instantaneous
in-use slabs in debugfs. But with increased usage of swiotlb for all I/O
in Confidential Computing (coco) VMs, it has become difficult to know
how much memory to allocate for swiotlb bounce buffers, either via the
automatic algorithm in the kernel or by specifying a value on the
kernel boot line. The current automatic algorithm generously allocates
swiotlb bounce buffer memory, and may be wasting significant memory in
many use cases.
To support better understanding of swiotlb usage, add tracking of the
the high water mark for usage of the default swiotlb bounce buffer memory
pool and any reserved memory pools. Report these high water marks in
debugfs along with the other swiotlb pool metrics. Allow the high water
marks to be reset to zero at runtime by writing to them.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
For io_tlb_nslabs, the debugfs code reports the correct value for a
specific reserved memory pool. But for io_tlb_used, the value reported
is always for the default pool, not the specific reserved pool. Fix this.
Fixes: 5c850d3188 ("swiotlb: fix passing local variable to debugfs_create_ulong()")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The reservedmem_of_init_fn's are invoked very early at boot before the
memory zones have even been defined. This makes it inappropriate to test
whether the page corresponding to a PFN is in ZONE_HIGHMEM from within
one.
Removing the check allows an ARM 32-bit kernel with SPARSEMEM enabled to
boot properly since otherwise we would be de-referencing an
uninitialized sparsemem map to perform pfn_to_page() check.
The arm64 architecture happens to work (and also has no high memory) but
other 32-bit architectures could also be having similar issues.
While it would be nice to provide early feedback about a reserved DMA
pool residing in highmem, it is not possible to do that until the first
time we try to use it, which is where the check is moved to.
Fixes: 0b84e4f8b7 ("swiotlb: Add restricted DMA pool initialization")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Since commit 8b41fc4454 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.
So remove it in the files in this commit, none of which can be built as
modules.
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: iommu@lists.linux.dev
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Provide a kconfig option to allow arches to manipulate default
value of dma_default_coherent in Kconfig.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
dma_default_coherent was decleared unconditionally at kernel/dma/mapping.c
but only decleared when any of non-coherent options is enabled in
dma-map-ops.h.
Guard the declaration in mapping.c with non-coherent options and provide
a fallback definition.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The alignment mask in swiotlb_do_find_slots() masks off the high
bits which are not relevant for the alignment, so multiple
requirements are combined with a bitwise OR rather than AND.
In plain English, the stricter the alignment, the more bits must
be set in iotlb_align_mask.
Confusion may arise from the fact that the same variable is also
used to mask off the offset within a swiotlb slot, which is
achieved with a bitwise AND.
Fixes: 0eee5ae102 ("swiotlb: fix slot alignment checks")
Reported-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz33r5zY7oAQ@mail.gmail.com/
Reported-by: Kelsey Steele <kelseysteele@linux.microsoft.com>
Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Tested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
On 32-bit without LPAE:
kernel/dma/debug.c: In function ‘debug_dma_dump_mappings’:
kernel/dma/debug.c:537:7: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 9 has type ‘phys_addr_t’ {aka ‘unsigned int’} [-Wformat=]
kernel/dma/debug.c: In function ‘dump_show’:
kernel/dma/debug.c:568:59: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 11 has type ‘phys_addr_t’ {aka ‘unsigned int’} [-Wformat=]
Fixes: bd89d69a52 ("dma-debug: add cacheline to user/kernel space dump messages")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/202303160548.ReyuTsGD-lkp@intel.com
Reported-by: noreply@ellerman.id.au
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Having the cacheline also printed on the debug_dma_dump_mappings() and
dump_show() is useful for debugging. Furthermore, this also standardizes
the messages shown on both dump functions.
Signed-off-by: Desnes Nunes <desnesn@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Small update on dma_debug_entry's struct commentary and also standardize
the usage of 'dma_addr' variable name from debug_dma_map_page() on
debug_dma_unmap_page(), and similarly on debug_dma_free_coherent()
Signed-off-by: Desnes Nunes <desnesn@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
