From b18fe4be59f215b1ce75f406d04810454f206faf Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 28 Jan 2019 18:18:08 +0000 Subject: [PATCH] drm/i915: Enlarge vma->pin_count Previously we only accommodated having a vma pinned by a small number of users, with the maximum being pinned for use by the display engine. As such, we used a small bitfield only large enough to allow the vma to be pinned twice (for back/front buffers) in each scanout plane. Keeping the maximum permissible pin_count small allows us to quickly catch a potential leak. However, as we want to split a 4096B page into 64 different cachelines and pin each cacheline for use by a different timeline, we will exceed the current maximum permissible vma->pin_count and so time has come to enlarge it. Whilst we are here, try to pull together the similar bits: Address/layout specification: - bias, mappable, zone_4g: address limit specifiers - fixed: address override, limits still apply though - high: not strictly an address limit, but an address direction to search Search controls: - nonblock, nonfault, noevict v2: Rewrite the guideline comment on bit consumption. Signed-off-by: Chris Wilson Reviewed-by: John Harrison Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_gtt.h | 26 ++++++++--------- drivers/gpu/drm/i915/i915_vma.h | 45 +++++++++++++++++++---------- 2 files changed, 42 insertions(+), 29 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h index bd679c8c56dd..03ade71b8d9a 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.h +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h @@ -642,19 +642,19 @@ int i915_gem_gtt_insert(struct i915_address_space *vm, /* Flags used by pin/bind&friends. */ #define PIN_NONBLOCK BIT_ULL(0) -#define PIN_MAPPABLE BIT_ULL(1) -#define PIN_ZONE_4G BIT_ULL(2) -#define PIN_NONFAULT BIT_ULL(3) -#define PIN_NOEVICT BIT_ULL(4) - -#define PIN_MBZ BIT_ULL(5) /* I915_VMA_PIN_OVERFLOW */ -#define PIN_GLOBAL BIT_ULL(6) /* I915_VMA_GLOBAL_BIND */ -#define PIN_USER BIT_ULL(7) /* I915_VMA_LOCAL_BIND */ -#define PIN_UPDATE BIT_ULL(8) - -#define PIN_HIGH BIT_ULL(9) -#define PIN_OFFSET_BIAS BIT_ULL(10) -#define PIN_OFFSET_FIXED BIT_ULL(11) +#define PIN_NONFAULT BIT_ULL(1) +#define PIN_NOEVICT BIT_ULL(2) +#define PIN_MAPPABLE BIT_ULL(3) +#define PIN_ZONE_4G BIT_ULL(4) +#define PIN_HIGH BIT_ULL(5) +#define PIN_OFFSET_BIAS BIT_ULL(6) +#define PIN_OFFSET_FIXED BIT_ULL(7) + +#define PIN_MBZ BIT_ULL(8) /* I915_VMA_PIN_OVERFLOW */ +#define PIN_GLOBAL BIT_ULL(9) /* I915_VMA_GLOBAL_BIND */ +#define PIN_USER BIT_ULL(10) /* I915_VMA_LOCAL_BIND */ +#define PIN_UPDATE BIT_ULL(11) + #define PIN_OFFSET_MASK (-I915_GTT_PAGE_SIZE) #endif diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h index 7252abc73d3e..5793abe509a2 100644 --- a/drivers/gpu/drm/i915/i915_vma.h +++ b/drivers/gpu/drm/i915/i915_vma.h @@ -71,29 +71,42 @@ struct i915_vma { unsigned int open_count; unsigned long flags; /** - * How many users have pinned this object in GTT space. The following - * users can each hold at most one reference: pwrite/pread, execbuffer - * (objects are not allowed multiple times for the same batchbuffer), - * and the framebuffer code. When switching/pageflipping, the - * framebuffer code has at most two buffers pinned per crtc. + * How many users have pinned this object in GTT space. * - * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3 - * bits with absolutely no headroom. So use 4 bits. + * This is a tightly bound, fairly small number of users, so we + * stuff inside the flags field so that we can both check for overflow + * and detect a no-op i915_vma_pin() in a single check, while also + * pinning the vma. + * + * The worst case display setup would have the same vma pinned for + * use on each plane on each crtc, while also building the next atomic + * state and holding a pin for the length of the cleanup queue. In the + * future, the flip queue may be increased from 1. + * Estimated worst case: 3 [qlen] * 4 [max crtcs] * 7 [max planes] = 84 + * + * For GEM, the number of concurrent users for pwrite/pread is + * unbounded. For execbuffer, it is currently one but will in future + * be extended to allow multiple clients to pin vma concurrently. + * + * We also use suballocated pages, with each suballocation claiming + * its own pin on the shared vma. At present, this is limited to + * exclusive cachelines of a single page, so a maximum of 64 possible + * users. */ -#define I915_VMA_PIN_MASK 0xf -#define I915_VMA_PIN_OVERFLOW BIT(5) +#define I915_VMA_PIN_MASK 0xff +#define I915_VMA_PIN_OVERFLOW BIT(8) /** Flags and address space this VMA is bound to */ -#define I915_VMA_GLOBAL_BIND BIT(6) -#define I915_VMA_LOCAL_BIND BIT(7) +#define I915_VMA_GLOBAL_BIND BIT(9) +#define I915_VMA_LOCAL_BIND BIT(10) #define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND | I915_VMA_PIN_OVERFLOW) -#define I915_VMA_GGTT BIT(8) -#define I915_VMA_CAN_FENCE BIT(9) -#define I915_VMA_CLOSED BIT(10) -#define I915_VMA_USERFAULT_BIT 11 +#define I915_VMA_GGTT BIT(11) +#define I915_VMA_CAN_FENCE BIT(12) +#define I915_VMA_CLOSED BIT(13) +#define I915_VMA_USERFAULT_BIT 14 #define I915_VMA_USERFAULT BIT(I915_VMA_USERFAULT_BIT) -#define I915_VMA_GGTT_WRITE BIT(12) +#define I915_VMA_GGTT_WRITE BIT(15) unsigned int active_count; struct rb_root active; -- 2.45.2