Chris Wilson 2d6692e642 drm/i915: Start writeback from the shrinker ... When we are called to relieve mempressue via the shrinker, the only way we can make progress is either by discarding unwanted pages (those objects that userspace has marked MADV_DONTNEED) or by reclaiming the dirty objects via swap. As we know that is the only way to make further progress, we can initiate the writeback as we invalidate the objects. This means the objects we put onto the inactive anon lru list are already marked for reclaim+writeback and so will trigger a wait upon the writeback inside direct reclaim, greatly improving the success rate of direct reclaim on i915 objects. The corollary is that we may start a slow swap on opportunistic mempressure from the likes of the compaction + migration kthreads. This is limited by those threads only being allowed to shrink idle pages, but also that if we reactivate the page before it is swapped out by gpu activity, we only page the cost of repinning the page. The cost is most felt when an object is reused after mempressure, which hopefully excludes the latency sensitive tasks (as we are just extending the impact of swap thrashing to them). Apparently this is not the first time we've had this idea. Back in commit 5537252b6b ("drm/i915: Invalidate our pages under memory pressure") we wanted to start writeback but settled on invalidate after Hugh Dickins warned us about a possibility of a deadlock within shmemfs if we started writeback from shrink_slab. Looking at the callchain, using writeback from i915_gem_shrink should be equivalent to the pageout also employed by shrink_slab, i.e. it should not be any riskier afaict. v2: Leave mmapings intact. At this point, the only mmapings of our objects will be via CPU mmaps on the shmemfs filp, which are out-of-scope for our LRU tracking. Instead leave those pages to the inactive anon LRU page list for aging and pageout as normal. v3: Be selective on which paths trigger writeback, in particular excluding paths shrinking just to reclaim vm space (e.g. mmap, vmap reapers) and avoid starting writeback on the entire process space from within the pm freezer. References: https://bugs.freedesktop.org/show_bug.cgi?id=108686 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Michal Hocko <mhocko@suse.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> #v1 Link: https://patchwork.freedesktop.org/patch/msgid/20190420115539.29081-1-chris@chris-wilson.co.uk		2019-04-20 15:06:31 +01:00
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amd
arc
arm
armada
ast
atmel-hlcdc
bochs
bridge
cirrus
etnaviv
exynos
fsl-dcu
gma500
hisilicon
i2c
i810
i915	drm/i915: Start writeback from the shrinker	2019-04-20 15:06:31 +01:00
imx
lib
mediatek
meson
mga
mgag200
msm
mxsfb
nouveau
omapdrm
panel
pl111
qxl
r128
radeon
rcar-du
rockchip
savage
scheduler
selftests
shmobile
sis
sti
stm
sun4i
tdfx
tegra
tilcdc
tinydrm
ttm
tve200
udl
v3d
vboxvideo
vc4
vgem
via
virtio
vkms
vmwgfx
xen
zte
ati_pcigart.c
drm_agpsupport.c
drm_atomic.c
drm_atomic_helper.c
drm_atomic_state_helper.c
drm_atomic_uapi.c
drm_auth.c
drm_blend.c
drm_bridge.c
drm_bufs.c
drm_cache.c
drm_client.c
drm_color_mgmt.c
drm_connector.c
drm_context.c
drm_crtc.c
drm_crtc_helper.c
drm_crtc_helper_internal.h
drm_crtc_internal.h
drm_damage_helper.c
drm_debugfs.c
drm_debugfs_crc.c
drm_dma.c
drm_dp_aux_dev.c
drm_dp_cec.c
drm_dp_dual_mode_helper.c
drm_dp_helper.c
drm_dp_mst_topology.c
drm_drv.c
drm_dsc.c
drm_dumb_buffers.c
drm_edid.c
drm_edid_load.c
drm_encoder.c
drm_encoder_slave.c
drm_fb_cma_helper.c
drm_fb_helper.c
drm_file.c
drm_flip_work.c
drm_fourcc.c
drm_framebuffer.c
drm_gem.c
drm_gem_cma_helper.c
drm_gem_framebuffer_helper.c
drm_gem_shmem_helper.c
drm_hashtab.c
drm_internal.h
drm_ioc32.c
drm_ioctl.c
drm_irq.c
drm_kms_helper_common.c
drm_lease.c
drm_legacy.h
drm_lock.c
drm_memory.c
drm_mipi_dsi.c
drm_mm.c
drm_mode_config.c
drm_mode_object.c
drm_modes.c
drm_modeset_helper.c
drm_modeset_lock.c
drm_of.c
drm_panel.c
drm_panel_orientation_quirks.c
drm_pci.c
drm_plane.c
drm_plane_helper.c
drm_prime.c
drm_print.c
drm_probe_helper.c
drm_property.c
drm_rect.c
drm_scatter.c
drm_scdc_helper.c
drm_simple_kms_helper.c
drm_syncobj.c
drm_sysfs.c
drm_trace.h
drm_trace_points.c
drm_vblank.c
drm_vm.c
drm_vma_manager.c
drm_writeback.c
Kconfig
Makefile