The use of kmap_atomic() is being deprecated in favor of
kmap_local_page()[1], and this patch converts the call from
kmap_atomic() + memcpy() to memcpy_[from/to]_page(), which use
kmap_local_page() to build local mapping and then do memcpy().
The main difference between atomic and local mappings is that local
mappings doesn't disable page faults or preemption (the preemption is
disabled for !PREEMPT_RT case, otherwise it only disables migration).
With kmap_local_page(), we can avoid the often unwanted side effect of
unnecessary page faults and preemption disables.
In drm/i915/gem/i915_gem_phys.c, the functions
i915_gem_object_get_pages_phys() and i915_gem_object_put_pages_phys()
don't need to disable pagefaults and preemption for mapping because of
2 reasons:
1. The flush operation is safe. In drm/i915/gem/i915_gem_object.c,
i915_gem_object_get_pages_phys() and i915_gem_object_put_pages_phys()
calls drm_clflush_virt_range() to use CLFLUSHOPT or WBINVD to flush.
Since CLFLUSHOPT is global on x86 and WBINVD is called on each cpu in
drm_clflush_virt_range(), the flush operation is global.
2. Any context switch caused by preemption or page faults (page fault
may cause sleep) doesn't affect the validity of local mapping.
Therefore, i915_gem_object_get_pages_phys() and
i915_gem_object_put_pages_phys() are two functions where the uses of
local mappings in place of atomic mappings are correctly suited.
Convert the calls of kmap_atomic() / kunmap_atomic() + memcpy() to
memcpy_from_page() and memcpy_to_page().
[1]: https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231203132947.2328805-3-zhao1.liu@linux.intel.com
Split out frontbuffer related declarations and static inlines from
gem/i915_gem_object.h into new gem/i915_gem_object_frontbuffer.h.
The main goal is to reduce header interdependencies. With
gem/i915_gem_object.h including display/intel_frontbuffer.h,
modification of the latter causes a whopping 300+ objects to be rebuilt,
while many of the source files actually needing it aren't explicitly
including it at all.
After the change, only 21 objects depend on display/intel_frontbuffer.h,
directly or indirectly.
Cc: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230830085127.2416842-1-jani.nikula@intel.com
There is an impedance mismatch between the scatterlist API using unsigned
int and our memory/page accounting in unsigned long. That is we may try
to create a scatterlist for a large object that overflows returning a
small table into which we try to fit very many pages. As the object size
is under the control of userspace, we have to be prudent and catch the
conversion errors.
To catch the implicit truncation we check before calling scattterlist
creation Apis. we use overflows_type check and report E2BIG if the
overflows may raise. When caller does not return errno, use WARN_ON to
report a problem.
This is already used in our create ioctls to indicate if the uABI request
is simply too large for the backing store. Failing that type check,
we have a second check at sg_alloc_table time to make sure the values
we are passing into the scatterlist API are not truncated.
v2: Move added i915_utils's macro into drm_util header (Jani N)
v5: Fix macros to be enclosed in parentheses for complex values
Fix too long line warning
v8: Replace safe_conversion() with check_assign() (Kees)
v14: Remove shadowing macros of scatterlist creation api and fix to
explicitly overflow check where the scatterlist creation APIs are
called. (Jani)
v15: Add missing returning of error code when the WARN_ON() has been
detected. (Jani)
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Brian Welty <brian.welty@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Co-developed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221228192252.917299-3-gwan-gyeong.mun@intel.com
We rely on page_sizes.sg in setup_scratch_page() reporting the correct
value if the underlying sgl is not contiguous, however in
get_pages_internal() we are only looking at the layout of the created
pages when calculating the sg_page_sizes, and not the final sgl, which
could in theory be completely different. In such a situation we might
incorrectly think we have a 64K scratch page, when it is actually only
4K or similar split over multiple non-contiguous entries, which could
lead to broken behaviour when touching the scratch space within the
padding of a 64K GTT page-table. For most of the other backends we
already just call i915_sg_dma_sizes() on the final mapping, so rather
just move that into __i915_gem_object_set_pages() to avoid such issues
coming back to bite us later.
v2: Update missing conversion in gvt
Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221108103238.165447-1-matthew.auld@intel.com
Give obj->mm.quirked a name much more reflective of its purpose
(i915_gem_object_has_tiling_quirk) and move it from the obj->mm field as
it doesn't denote a quirk of the backing store, but a quirk in the
object in its treatment of the backing pages, similar to tiling modes.
Then instead of abusing the pinned status of the buffer to protect it
from the shrinker, we can instead hide the buffer from the shrinker so
it is never considered for being swapped.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119214336.1463-4-chris@chris-wilson.co.uk
The obj->stolen is currently used to identify an object allocated from
stolen memory. This dates back to when there were just 1.5 types of
objects, an object backed by shmemfs and an object backed by shmemfs
with a contiguous physical address. Now that we have several different
types of objects, we no longer want to treat stolen objects as a special
case.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119214336.1463-3-chris@chris-wilson.co.uk
Catch up with upstream, in particular to get c1e8d7c6a7 ("mmap locking
API: convert mmap_sem comments").
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
The trouble with having a plain nesting flag for locks which do not
naturally nest (unlike block devices and their partitions, which is
the original motivation for nesting levels) is that lockdep will
never spot a true deadlock if you screw up.
This patch is an attempt at trying better, by highlighting a bit more
of the actual nature of the nesting that's going on. Essentially we
have two kinds of objects:
- objects without pages allocated, which cannot be on any lru and are
hence inaccessible to the shrinker.
- objects which have pages allocated, which are on an lru, and which
the shrinker can decide to throw out.
For the former type of object, memory allocations while holding
obj->mm.lock are permissible. For the latter they are not. And
get/put_pages transitions between the two types of objects.
This is still not entirely fool-proof since the rules might change.
But as long as we run such a code ever at runtime lockdep should be
able to observe the inconsistency and complain (like with any other
lockdep class that we've split up in multiple classes). But there are
a few clear benefits:
- We can drop the nesting flag parameter from
__i915_gem_object_put_pages, because that function by definition is
never going allocate memory, and calling it on an object which
doesn't have its pages allocated would be a bug.
- We strictly catch more bugs, since there's not only one place in the
entire tree which is annotated with the special class. All the
other places that had explicit lockdep nesting annotations we're now
going to leave up to lockdep again.
- Specifically this catches stuff like calling get_pages from
put_pages (which isn't really a good idea, if we can call get_pages
so could the shrinker). I've seen patches do exactly that.
Of course I fully expect CI will show me for the fool I am with this
one here :-)
v2: There can only be one (lockdep only has a cache for the first
subclass, not for deeper ones, and we don't want to make these locks
even slower). Still separate enums for better documentation.
Real fix: don't forget about phys objs and pin_map(), and fix the
shrinker to have the right annotations ... silly me.
v3: Forgot usertptr too ...
v4: Improve comment for pages_pin_count, drop the IMPORTANT comment
and instead prime lockdep (Chris).
v5: Appease checkpatch, no double empty lines (Chris)
v6: More rebasing over selftest changes. Also somehow I forgot to
push this patch :-/
Also format comments consistently while at it.
v7: Fix typo in commit message (Joonas)
Also drop the priming, with the lmem merge we now have allocations
while holding the lmem lock, which wreaks the generic priming I've
done in earlier patches. Should probably be resurrected when lmem is
fixed. See
commit 232a6ebae4
Author: Matthew Auld <matthew.auld@intel.com>
Date: Tue Oct 8 17:01:14 2019 +0100
drm/i915: introduce intel_memory_region
I'm keeping the priming patch locally so it wont get lost.
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "Tang, CQ" <cq.tang@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v5)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v6)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191105090148.30269-1-daniel.vetter@ffwll.ch
[mlankhorst: Fix commit typos pointed out by Michael Ruhl]
Since reservation_object_fini() does an immediate free, rather than
kfree_rcu as normal, we have to delay the release until after the RCU
grace period has elapsed (i.e. from the rcu cleanup callback) so that we
can rely on the RCU protected access to the fences while the object is a
zombie.
i915_gem_busy_ioctl relies on having an RCU barrier to protect the
reservation in order to avoid having to take a reference and strong
memory barriers.
v2: Order is important; only release after putting the pages!
Fixes: c03467ba40 ("drm/i915/gem: Free pages before rcu-freeing the object")
Testcase: igt/gem_busy/close-race
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190703180601.10950-1-chris@chris-wilson.co.uk
As we have dropped the final reference to the object, we do not need to
wait until after the rcu grace period to drop its pages. We still require
struct_mutex to completely unbind the object to release the pages, so we
still need a free-worker to manage that from process context. By
scheduling the release of pages before waiting for the rcu should mean
that we are not trapping those pages from beyond the reach of the
shrinker.
v2: Pass along the request to skip if the vma is busy to the underlying
unbind routine, to avoid checking the reservation underneath the
i915->mm.obj_lock which may be used from inside irq context.
v3: Flip the bit for unbinding while active, for later convenience.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111035
Fixes: a93615f900 ("drm/i915: Throw away the active object retirement complexity")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190703091726.11690-6-chris@chris-wilson.co.uk
