kern_yield(0) effectively causes the calling thread to be rescheduled
immediately since it resets the thread's priority to the highest possible
value. This can cause livelocks when the pattern
"while (!trylock()) kern_yield(0);" is used since the thread holding the
lock may linger on the runqueue for the CPU on which the looping thread is
running.
MFC after: 1 week
The intended use is to annotate frequently used globals which either rarely
change (and thus can be grouped in the same cacheline) or are an atomic counter
(which means it may benefit from being the only variable in the cacheline).
Linker script support is provided only for amd64. Architectures without it risk
having other variables put in, i.e. as if they were not annotated. This is
harmless from correctness point of view.
Reviewed by: bde (previous version)
MFC after: 1 month
If system starts without attached monitor, DRM create framebuffer
for VT console. Later, when monitor is attached, the hotplug event must
issue full modeset procedure to setup CRTC.
In original code, this was done in drm_fb_helper_set_par(), but we don't
have this function implemented yet. Use unrolled version of
drm_fb_helper_set_par() to ensure same functionality.
MFC after: 1 month
In particular, the fault access type is accounted for when the
aperture page is moved to GTT domain. On the other hand, the current
pager structure is left intact, most important, only one page is
instantiated per populate call.
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Suppose that we have an exclusively busy page, and a thread which can
accept shared-busy page. In this case, typical code waiting for the
page xbusy state to pass is
again:
VM_OBJECT_WLOCK(object);
...
if (vm_page_xbusied(m)) {
vm_page_lock(m);
VM_OBJECT_WUNLOCK(object); <---1
vm_page_busy_sleep(p, "vmopax");
goto again;
}
Suppose that the xbusy state owner locked the object, unbusied the
page and unlocked the object after we are at the line [1], but before we
executed the load of the busy_lock word in vm_page_busy_sleep(). If it
happens that there is still no waiters recorded for the busy state,
the xbusy owner did not acquired the page lock, so it proceeded.
More, suppose that some other thread happen to share-busy the page
after xbusy state was relinquished but before the m->busy_lock is read
in vm_page_busy_sleep(). Again, that thread only needs vm_object lock
to proceed. Then, vm_page_busy_sleep() reads busy_lock value equal to
the VPB_SHARERS_WORD(1).
In this case, all tests in vm_page_busy_sleep(9) pass and we are going
to sleep, despite the page being share-busied.
Update check for m->busy_lock == VPB_UNBUSIED in vm_page_busy_sleep(9)
to also accept shared-busy state if we only wait for the xbusy state to
pass.
Merge sequential if()s with the same 'then' clause in
vm_page_busy_sleep().
Note that the current code does not share-busy pages from parallel
threads, the only way to have more that one sbusy owner is right now
is to recurse.
Reported and tested by: pho (previous version)
Reviewed by: alc, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D8196
just with INVARIANTS
rwatson's point was valid in the sense that if the data passed at runtime is
invalid, it should always trip the invariant, not just in the debug case.
This is a deterrent against malicious input, or input caused by hardware
errors.
MFC after: 4 days
X-MFC with: r302577
Requested by: rwatson
Sponsored by: EMC / Isilon Storage Division
By definition (enum __drm_capabilities), cases other than CAP_SYS_ADMIN
aren't possible. Add in a KASSERT safety belt and return false in
!INVARIANTS case if an invalid value is passed in, as it would be a
programmer error.
This fixes a -Wreturn-type error with gcc 5.3.0.
Differential Revision: https://reviews.freebsd.org/D7188
MFC after: 1 week
Reported by: devel/amd64-gcc (5.3.0)
Reviewed by: dumbbell
Sponsored by: EMC / Isilon Storage Division
That check wasn't enough to handle appending a two byte character
following it.
This prevented my T400 (Intel Core 2 Duo P8400) from attaching;
it would panic from a stack overflow detection.
MacBookPro and i915kms_load="YES" in /boot/loader.conf.
A lowlevel timeout in one of the display ports caused an infinite wait
because a ticks/jiffies comparison was constant. The clock subsystem
which makes ticks/jiffies increment is started after the initial
driver probing is done. Refer to sys/kernel.h and SI_SUB_DRIVERS vs
SI_SUB_CLOCKS .
Discussed with: kmacy @
bus_get_cpus() returns a specified set of CPUs for a device. It accepts
an enum for the second parameter that indicates the type of cpuset to
request. Currently two valus are supported:
- LOCAL_CPUS (on x86 this returns all the CPUs in the package closest to
the device when DEVICE_NUMA is enabled)
- INTR_CPUS (like LOCAL_CPUS but only returns 1 SMT thread for each core)
For systems that do not support NUMA (or if it is not enabled in the kernel
config), LOCAL_CPUS fails with EINVAL. INTR_CPUS is mapped to 'all_cpus'
by default. The idea is that INTR_CPUS should always return a valid set.
Device drivers which want to use per-CPU interrupts should start using
INTR_CPUS instead of simply assigning interrupts to all available CPUs.
In the future we may wish to add tunables to control the policy of
INTR_CPUS (e.g. should it be local-only or global, should it ignore
SMT threads or not).
The x86 nexus driver exposes the internal set of interrupt CPUs from the
the x86 interrupt code via INTR_CPUS.
The ACPI bus driver and PCI bridge drivers use _PXM to return a suitable
LOCAL_CPUS set when _PXM exists and DEVICE_NUMA is enabled. They also and
the global INTR_CPUS set from the nexus driver with the per-domain set from
_PXM to generate a local INTR_CPUS set for child devices.
Reviewed by: wblock (manpage)
Differential Revision: https://reviews.freebsd.org/D5519
The local of the same name would alias the global, but we didn't even include
the header that defines tsc_freq. Include it and rename the local.
Reported by: Coverity
CID: 1331559
Sponsored by: EMC / Isilon Storage Division
pagers fault routines always return with a result page, be it the
proper and valid result page, or initially passed freshly allocated
placeholder. Do not free the passed in page until we are able to
provide the replacement, and do not assign NULL to *mres.
Reported and tested by: dumbbell
Reviewed by: royger (who also verified that Xen code is safe)
Sponsored by: The FreeBSD Foundation
This write came from Linux commit b4ae3f22d238 which has been implicated
in Sandy Bridge power consumption issues (albeit under different
conditions on Linux). Disabling it restores normal power consumption on
my Sandy Bridge laptop (Thinkpad X220).
PR: 207889
Reviewed by: cem, dumbbell
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5665
This makes sure the default context of each ring is cleaned up with the
ring itself and fixes a memory leak.
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date: Fri May 3 16:29:08 2013 +0300
drm/i915: unreference default context on module unload
Before module unload is called, gpu_idle() will switch
to default context. This will increment ref count of base
object as the default context is 'running' on module unload
time. Unreference the drm object so that when context
is freed, base object is freed as well.
v2: added comment to explain the refcounts (Ben Widawsky)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Obtained from: Linux
This fixes several memory leaks. Apparently, this problem exists in
Linux 3.8 but the code changed in Linux 3.9 so it may be fixed upstream
already. Still, this is something we need to pay attention to.
... when __wait_seqno() is interrupted by a signal. In this case,
__wait_seqno() returns -ERESTARTSYS. Like we already do in drm_ioctl(),
we need to convert this error to a common code such as -EINTR, so the
page fault handler is restarted.
Reported by: Frederic Chardon <chardon.frederic@gmail.com>
Tested by: Frederic Chardon <chardon.frederic@gmail.com>
This fixes the following error:
kernel: error: [drm:pid1167:drm_release] *ERROR* Device busy: 2
Because of that, drm_lastclose() was not called, leading to a few memory
leaks once the driver was unloaded.
MFC after: 1 week
This update brings initial support for Haswell GPUs.
Tested by: Many users of FreeBSD, PC-BSD and HardenedBSD
Relnotes: yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5554
taskqueue_enqueue() was changed to support both fast and non-fast
taskqueues 10 years ago in r154167. It has been a compat shim ever
since. It's time for the compat shim to go.
Submitted by: Howard Su <howard0su@gmail.com>
Reviewed by: sephe
Differential Revision: https://reviews.freebsd.org/D5131
address and use this mechanism when:
1. kmem_alloc_{attr,contig}() can't find suitable free pages in the physical
memory allocator's free page lists. This replaces the long-standing
approach of scanning the inactive and inactive queues, converting clean
pages into PG_CACHED pages and laundering dirty pages. In contrast, the
new mechanism does not use PG_CACHED pages nor does it trigger a large
number of I/O operations.
2. on 32-bit MIPS processors, uma_small_alloc() and the pmap can't find
free pages in the physical memory allocator's free page lists that are
covered by the direct map. Tested by: adrian
3. ttm_bo_global_init() and ttm_vm_page_alloc_dma32() can't find suitable
free pages in the physical memory allocator's free page lists.
In the coming months, I expect that this new mechanism will be applied in
other places. For example, balloon drivers should use relocation to
minimize fragmentation of the guest physical address space.
Make vm_phys_alloc_contig() a little smarter (and more efficient in some
cases). Specifically, use vm_phys_segs[] earlier to avoid scanning free
page lists that can't possibly contain suitable pages.
Reviewed by: kib, markj
Glanced at: jhb
Discussed with: jeff
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D4444
instead of GMBUS access for I2C transfers. The GMBUS driver falls back
to this mode when a transfer times out. However, the first transfer to
timeout was sending the request back to itself resulting in an panic due
to recursing on a lock. Fix it to forward the request on to the proper
device. This appears to have been accidentally changed in r277487.
Reported by: Joe Maloney <jmaloney@pcbsd.org>
Reviewed by: adrian, dumbbell, imp
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D4599
o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return, like it was
done before with the 'reqpage' only. Now the reqpage goes away. With
new interface it is easier to implement code protected from race
conditions.
Such arrayed requests for now should be preceeded by a call to
vm_pager_haspage() to make sure that request is possible. This
could be improved later, making vm_pager_haspage() obsolete.
Strenghtening the promises on the business of the array of pages
allows us to remove such hacks as swp_pager_free_nrpage() and
vm_pager_free_nonreq().
o New KPI accepts two integer pointers that may optionally point at
values for read ahead and read behind, that a pager may do, if it
can. These pages are completely owned by pager, and not controlled
by the caller.
This shifts the UFS-specific readahead logic from vm_fault.c, which
should be file system agnostic, into vnode_pager.c. It also removes
one VOP_BMAP() request per hard fault.
Discussed with: kib, alc, jeff, scottl
Sponsored by: Nginx, Inc.
Sponsored by: Netflix
