GFP_TEMPORARY was introduced by commit e12ba74d8f ("Group short-lived
and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's
primary motivation was to allow users to tell that an allocation is
short lived and so the allocator can try to place such allocations close
together and prevent long term fragmentation. As much as this sounds
like a reasonable semantic it becomes much less clear when to use the
highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the
context holding that memory sleep? Can it take locks? It seems there is
no good answer for those questions.
The current implementation of GFP_TEMPORARY is basically GFP_KERNEL |
__GFP_RECLAIMABLE which in itself is tricky because basically none of
the existing caller provide a way to reclaim the allocated memory. So
this is rather misleading and hard to evaluate for any benefits.
I have checked some random users and none of them has added the flag
with a specific justification. I suspect most of them just copied from
other existing users and others just thought it might be a good idea to
use without any measuring. This suggests that GFP_TEMPORARY just
motivates for cargo cult usage without any reasoning.
I believe that our gfp flags are quite complex already and especially
those with highlevel semantic should be clearly defined to prevent from
confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and
replace all existing users to simply use GFP_KERNEL. Please note that
SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and
so they will be placed properly for memory fragmentation prevention.
I can see reasons we might want some gfp flag to reflect shorterm
allocations but I propose starting from a clear semantic definition and
only then add users with proper justification.
This was been brought up before LSF this year by Matthew [1] and it
turned out that GFP_TEMPORARY really doesn't have a clear semantic. It
seems to be a heuristic without any measured advantage for most (if not
all) its current users. The follow up discussion has revealed that
opinions on what might be temporary allocation differ a lot between
developers. So rather than trying to tweak existing users into a
semantic which they haven't expected I propose to simply remove the flag
and start from scratch if we really need a semantic for short term
allocations.
[1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org
[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: drm/i915: fix up]
Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull i916 drm fixes from Rodrigo Vivi:
"Since Dave is on paternity leave we are sending drm/i915 fixes for
v4.14-rc1 directly to you as he had asked us to do.
The most critical ones are the GPU reset fix for gen2-4 and GVT fix
for a regression that is blocking gvt init to work on your tree.
The rest is general fixes for patches coming from drm-next"
Acked-by: Dave Airlie <airlied@redhat.com>
* tag 'drm-intel-next-fixes-2017-09-07' of git://anongit.freedesktop.org/git/drm-intel:
drm/i915: Re-enable GTT following a device reset
drm/i915: Annotate user relocs with __user
drm/i915: Silence sparse by using gfp_t
drm/i915: Add __rcu to radix tree slot pointer
drm/i915: Fix the missing PPAT cache attributes on CNL
drm/i915/gvt: Remove one duplicated MMIO
drm/i915: Fix enum pipe vs. enum transcoder for the PCH transcoder
drm/i915: Make i2c lock ops static
drm/i915: Make i9xx_load_ycbcr_conversion_matrix() static
drm/i915/edp: Increase T12 panel delay to 900 ms to fix DP AUX CH timeouts
drm/i915: Ignore duplicate VMA stored within the per-object handle LUT
drm/i915: Skip fence alignemnt check for the CCS plane
drm/i915: Treat fb->offsets[] as a raw byte offset instead of a linear offset
drm/i915: Always wake the device to flush the GTT
drm/i915: Recreate vmapping even when the object is pinned
drm/i915: Quietly cancel FBC activation if CRTC is turned off before worker
Enable the guest i915 full ppgtt functionality when host can provide this
capability. vgt_caps is introduced to guest i915 driver to get the vgpu
capabilities from the device model. VGT_CPAS_FULL_PPGTT is one of the
capabilities type to let guest i915 dirver know that the guest i915 full
ppgtt is supported by device model.
Notice that the minor version of pvinfo isn't bumped because of this
vgt_caps introduction, due to older guest would be broken by simply
increasing the pvinfo version. Although the pvinfo minor version doesn't
increase, the compatibility won't be blocked. The compatibility is ensured
by checking the value of caps field in pvinfo. Zero means no full ppgtt
support and BIT(2) means this feature is provided.
Changes since v1:
- Use u32 instead of uint32_t (Joonas)
- Move VGT_CAPS_FULL_PPGTT introduction to this patch and use #define
instead of enum (Joonas)
- Rewrite the vgpu full ppgtt capability checking logic. (Joonas)
- Some coding style refine. (Joonas)
Changes since v2:
- Divide the whole patch set into two separate patch series, with one
patch in i915 side to check guest i915 full ppgtt capability and enable
it when this capability is supported by the device model, and the other
one in gvt side which fixs the blocking issue and enables the device
model to provide the capability to guest. And this patch focuses on guest
i915 side. (Joonas)
- Change the title from "introduce vgt_caps to pvinfo" to
"Enable guest i915 full ppgtt functionality". (Tina)
Change since v3:
- Add some comments about pvinfo caps and version. (Joonas)
Change since v4:
- Tested by Tina Zhang.
Change since v5:
- Add limitation about supporting 32bit full ppgtt.
Change since v6:
- Change the fallback to 48bit full ppgtt if i915.ppgtt_enable=2. (Zhenyu)
Change in v9:
- Remove the fixme comment due to no plan for 32bit full ppgtt
support. (Zhenyu)
- Reorder the patch-set to fix compiling issue with git-bisect. (Zhenyu)
- Add print log when forcing guest 48bit full ppgtt. (Zhenyu)
v10:
- Update against Joonas's has_full_ppgtt and has_full_48bit_ppgtt disconnect
change. (Zhenyu)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> # in v2
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
When choosing a slot for an execbuffer, we ideally want to use the same
address as last time (so that we don't have to rebind it) and the same
address as expected by the user (so that we don't have to fixup any
relocations pointing to it). If we first try to bind the incoming
execbuffer->offset from the user, or the currently bound offset that
should hopefully achieve the goal of avoiding the rebind cost and the
relocation penalty. However, if the object is not currently bound there
we don't want to arbitrarily unbind an object in our chosen position and
so choose to rebind/relocate the incoming object instead. After we
report the new position back to the user, on the next pass the
relocations should have settled down.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtien@linux.intel.com>
More stuff for 4.13:
- skl+ wm fixes from Mahesh Kumar
- some refactor and tests for i915_sw_fence (Chris)
- tune execlist/scheduler code (Chris)
- g4x,g33 gpu reset improvements (Chris, Mika)
- guc code cleanup (Michal Wajdeczko, Michał Winiarski)
- dp aux backlight improvements (Puthikorn Voravootivat)
- buffer based guc/host communication (Michal Wajdeczko)
* tag 'drm-intel-next-2017-05-29' of git://anongit.freedesktop.org/git/drm-intel: (253 commits)
drm/i915: Update DRIVER_DATE to 20170529
drm/i915: Keep the forcewake timer alive for 1ms past the most recent use
drm/i915/guc: capture GuC logs if FW fails to load
drm/i915/guc: Introduce buffer based cmd transport
drm/i915/guc: Disable send function on fini
drm: Add definition for eDP backlight frequency
drm/i915: Drop AUX backlight enable check for backlight control
drm/i915: Consolidate #ifdef CONFIG_INTEL_IOMMU
drm/i915: Only GGTT vma may be pinned and prevent shrinking
drm/i915: Serialize GTT/Aperture accesses on BXT
drm/i915: Convert i915_gem_object_ops->flags values to use BIT()
drm/i915/selftests: Silence compiler warning in igt_ctx_exec
drm/i915/guc: Skip port assign on first iteration of GuC dequeue
drm/i915: Remove misleading comment in request_alloc
drm/i915/g33: Improve reset reliability
Revert "drm/i915: Restore lost "Initialized i915" welcome message"
drm/i915/huc: Update GLK HuC version
drm/i915: Check for allocation failure
drm/i915/guc: Remove action status and statistics from debugfs
drm/i915/g4x: Improve gpu reset reliability
...
BXT has a H/W issue with IOMMU which can lead to system hangs when
Aperture accesses are queued within the GAM behind GTT Accesses.
This patch avoids the condition by wrapping all GTT updates in stop_machine
and using a flushing read prior to restarting the machine.
The stop_machine guarantees no new Aperture accesses can begin while
the PTE writes are being emmitted. The flushing read ensures that
any following Aperture accesses cannot begin until the PTE writes
have been cleared out of the GAM's fifo.
Only FOLLOWING Aperture accesses need to be separated from in flight
PTE updates. PTE Writes may follow tightly behind already in flight
Aperture accesses, so no flushing read is required at the start of
a PTE update sequence.
This issue was reproduced by running
igt/gem_readwrite and
igt/gem_render_copy
simultaneously from different processes, each in a tight loop,
with INTEL_IOMMU enabled.
This patch was originally published as:
drm/i915: Serialize GTT Updates on BXT
v2: Move bxt/iommu detection into static function
Remove #ifdef CONFIG_INTEL_IOMMU protection
Make function names more reflective of purpose
Move flushing read into static function
v3: Tidy up for checkpatch.pl
Testcase: igt/gem_concurrent_blit
Signed-off-by: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: John Harrison <john.C.Harrison@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1495641251-30022-1-git-send-email-jon.bloomfield@intel.com
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Now that drm_[cm]alloc* helpers are simple one line wrappers around
kvmalloc_array and drm_free_large is just kvfree alias we can drop
them and replace by their native forms.
This shouldn't introduce any functional change.
Changes since v1
- fix typo in drivers/gpu//drm/etnaviv/etnaviv_gem.c - noticed by 0day
build robot
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Michal Hocko <mhocko@suse.com>drm: drop drm_[cm]alloc* helpers
[danvet: Fixup vgem which grew another user very recently.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517122312.GK18247@dhcp22.suse.cz
If a vma is already bound to a ppgtt, we incorrectly call
allocate_va_range again when doing a PIN_UPDATE, which will result in
over accounting within our paging structures, such that when we do
unbind something we don't actually destroy the structures and end up
inadvertently recycling them. In reality this probably isn't too bad,
but once we start touching PDEs and PDPEs for 64K/2M/1G pages this
apparent recycling will manifest into lots of really, really subtle
bugs.
v2: Fix the testing of vma->flags for aliasing_ppgtt_bind_vma
Fixes: ff685975d9 ("drm/i915: Move allocate_va_range to GTT")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170512091423.26085-1-chris@chris-wilson.co.uk
If we setup the vm size early, we can use the newly introduced
i915_vm_is_48bit() in majority of callsites wanting to know the vm size.
As we operate either with 3lvl or 4lvl page table structure,
wrap the vm size query inside a function which tells us if
4lvl setup is needed for particular vm, as the following
code uses the function names where level is noted.
v2: use_4lvl (Chris)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1488295691-9404-3-git-send-email-mika.kuoppala@intel.com
Testing with concurrent GGTT accesses no longer show the coherency
problems from yonder, commit 5bab6f60cb ("drm/i915: Serialise updates
to GGTT with access through GGTT on Braswell"). My presumption is that
the root cause was more likely fixed by commit 3b5724d702 ("drm/i915:
Wait for writes through the GTT to land before reading back"), along
with the use of WC updates to the global gTT in commit 8448661d65
("drm/i915: Convert clflushed pagetables over to WC maps". Given
that the original symptoms can no longer be reproduced, time to remove
the workaround.
Testcase: igt/gem_concurrent_blit
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170220124718.14796-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
The hardware does not cope very well with us changing the PD within an
active context (the context must be idle for it to re-read the PD). As
we only check whether the page is idle before changing the entry (and on
through the PD tree), we cannot reliably replace PD entries on
gen6/gen7. To fully avoid changing the tree at runtime, preallocate it
on init.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170215084357.19977-9-chris@chris-wilson.co.uk
