as it is required by i915kms driver from Linux kernel v 5.5.
This is done with asynchronous freeing of requested memory areas from
taskqueue thread. As memory to be freed is reused to store linked list
entry, backing UMA zone item size is rounded up to pointer size.
While here, make struct linux_kmem_cache private to LKPI to reduce amount
of BSD headers included by linux/slab.h and switch RCU code to usage of
LKPI's linux_irq_work_tq taskqueue to avoid injection of current into
system-wide taskqueue_fast thread context.
Submitted by: nc (initial version for drm-kmod)
Reviewed by: manu, nc
Differential revision: https://reviews.freebsd.org/D30760
Summary:
Linux's irq_work queue was created for asynchronous execution of code from contexts where spin_lock's are not available like "hardware interrupt context". FreeBSD's fast taskqueues was created for the same purposes.
Drm-kmod 5.4 uses irq_work_queue() at least in one place to schedule execution of task/work from the critical section that triggers following INVARIANTS-induced panic:
```
panic: acquiring blockable sleep lock with spinlock or critical section held (sleep mutex) linuxkpi_short_wq @ /usr/src/sys/kern/subr_taskqueue.c:281
cpuid = 6
time = 1605048416
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe006b538c90
vpanic() at vpanic+0x182/frame 0xfffffe006b538ce0
panic() at panic+0x43/frame 0xfffffe006b538d40
witness_checkorder() at witness_checkorder+0xf3e/frame 0xfffffe006b538f00
__mtx_lock_flags() at __mtx_lock_flags+0x94/frame 0xfffffe006b538f50
taskqueue_enqueue() at taskqueue_enqueue+0x42/frame 0xfffffe006b538f70
linux_queue_work_on() at linux_queue_work_on+0xe9/frame 0xfffffe006b538fb0
irq_work_queue() at irq_work_queue+0x21/frame 0xfffffe006b538fd0
semaphore_notify() at semaphore_notify+0xb2/frame 0xfffffe006b539020
__i915_sw_fence_notify() at __i915_sw_fence_notify+0x2e/frame 0xfffffe006b539050
__i915_sw_fence_complete() at __i915_sw_fence_complete+0x63/frame 0xfffffe006b539080
i915_sw_fence_complete() at i915_sw_fence_complete+0x8e/frame 0xfffffe006b5390c0
dma_i915_sw_fence_wake() at dma_i915_sw_fence_wake+0x4f/frame 0xfffffe006b539100
dma_fence_signal_locked() at dma_fence_signal_locked+0x105/frame 0xfffffe006b539180
dma_fence_signal() at dma_fence_signal+0x72/frame 0xfffffe006b5391c0
dma_fence_is_signaled() at dma_fence_is_signaled+0x80/frame 0xfffffe006b539200
dma_resv_add_shared_fence() at dma_resv_add_shared_fence+0xb3/frame 0xfffffe006b539270
i915_vma_move_to_active() at i915_vma_move_to_active+0x18a/frame 0xfffffe006b5392b0
eb_move_to_gpu() at eb_move_to_gpu+0x3ad/frame 0xfffffe006b539320
eb_submit() at eb_submit+0x15/frame 0xfffffe006b539350
i915_gem_do_execbuffer() at i915_gem_do_execbuffer+0x7d4/frame 0xfffffe006b539570
i915_gem_execbuffer2_ioctl() at i915_gem_execbuffer2_ioctl+0x1c1/frame 0xfffffe006b539600
drm_ioctl_kernel() at drm_ioctl_kernel+0xd9/frame 0xfffffe006b539670
drm_ioctl() at drm_ioctl+0x5cd/frame 0xfffffe006b539820
linux_file_ioctl() at linux_file_ioctl+0x323/frame 0xfffffe006b539880
kern_ioctl() at kern_ioctl+0x1f4/frame 0xfffffe006b5398f0
sys_ioctl() at sys_ioctl+0x12a/frame 0xfffffe006b5399c0
amd64_syscall() at amd64_syscall+0x121/frame 0xfffffe006b539af0
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe006b539af0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x800a6f09a, rsp = 0x7fffffffe588, rbp = 0x7fffffffe640 ---
KDB: enter: panic
```
Here, the dma_resv_add_shared_fence() performs a critical_enter() and following call of schedule_work() from semaphore_notify() triggers 'acquiring blockable sleep lock with spinlock or critical section held' panic.
Switching irq_work implementation to fast taskqueue fixes the panic for me.
Other report with the similar bug: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247166
Reviewed By: hselasky
Differential Revision: https://reviews.freebsd.org/D27171
In Linux, ksize() gets the actual amount of memory allocated for a given
object. This commit adds malloc_usable_size() to FreeBSD KPI which does
the same. It also maps LinuxKPI ksize() to newly created function.
ksize() function is used by drm-kmod.
Reviewed by: hselasky, kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D26215
Put large functions into linux_slab.c instead of declaring them static
inline.
Add support for more memory allocation wrappers like kmalloc_array()
and __vmalloc().
Make sure either the M_WAITOK or the M_NOWAIT flag is set and mask
away unused memory allocation flags before calling FreeBSD's malloc()
routine.
Move kmalloc_node() definition to slab.h where it belongs.
Implement support for the SLAB_DESTROY_BY_RCU feature when creating a
kmem_cache which basically means kmem_cache memory is freed using
call_rcu().
MFC after: 1 week
Sponsored by: Mellanox Technologies
conflict with the opensolaris kernel module.
This patch solves a problem where the kernel linker will incorrectly
resolve opensolaris kmem_xxx() functions as linuxkpi ones, which leads
to a panic when these functions are used.
Submitted by: gallatin @
Sponsored by: Mellanox Technologies
MFC after: 1 week
- Move all files related to the LinuxKPI into sys/compat/linuxkpi and
its subfolders.
- Update sys/conf/files and some Makefiles to use new file locations.
- Added description of COMPAT_LINUXKPI to sys/conf/NOTES which in turn
adds the LinuxKPI to all LINT builds.
- The LinuxKPI can be added to the kernel by setting the
COMPAT_LINUXKPI option. The OFED kernel option no longer builds the
LinuxKPI into the kernel. This was done to keep the build rules for
the LinuxKPI in sys/conf/files simple.
- Extend the LinuxKPI module to include support for USB by moving the
Linux USB compat from usb.ko to linuxkpi.ko.
- Bump the FreeBSD_version.
- A universe kernel build has been done.
Reviewed by: np @ (cxgb and cxgbe related changes only)
Sponsored by: Mellanox Technologies
