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![Chris Wilson](/assets/img/avatar_default.png)
Another month, another story in the cache coherency saga. This time, we
come to the realisation that i915_gem_object_is_coherent() has been
reporting whether we can read from the target without requiring a cache
invalidate; but we were using it in places for testing whether we could
write into the object without requiring a cache flush. So split the
tracking into two, one to decide before reads, one after writes.
See commit e27ab73d17
("drm/i915: Mark CPU cache as dirty on every
transition for CPU writes") for the previous entry in this saga.
v2: Be verbose
v3: Remove unused function (i915_gem_object_is_coherent)
v4: Fix inverted coherency check prior to execbuf (from v2)
v5: Add comment for nasty code where we are optimising on gcc's behalf.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101109
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101555
Testcase: igt/kms_mmap_write_crc
Testcase: igt/kms_pwrite_crc
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170811111116.10373-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
199 lines
5.6 KiB
C
199 lines
5.6 KiB
C
/*
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* Copyright © 2014-2016 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <drm/drmP.h>
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#include <drm/i915_drm.h>
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#include "i915_drv.h"
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#define QUIET (__GFP_NORETRY | __GFP_NOWARN)
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/* convert swiotlb segment size into sensible units (pages)! */
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#define IO_TLB_SEGPAGES (IO_TLB_SEGSIZE << IO_TLB_SHIFT >> PAGE_SHIFT)
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static void internal_free_pages(struct sg_table *st)
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{
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struct scatterlist *sg;
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for (sg = st->sgl; sg; sg = __sg_next(sg)) {
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if (sg_page(sg))
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__free_pages(sg_page(sg), get_order(sg->length));
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}
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sg_free_table(st);
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kfree(st);
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}
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static struct sg_table *
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i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
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{
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struct drm_i915_private *i915 = to_i915(obj->base.dev);
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struct sg_table *st;
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struct scatterlist *sg;
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unsigned int npages;
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int max_order;
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gfp_t gfp;
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max_order = MAX_ORDER;
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#ifdef CONFIG_SWIOTLB
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if (swiotlb_nr_tbl()) {
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unsigned int max_segment;
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max_segment = swiotlb_max_segment();
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if (max_segment) {
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max_segment = max_t(unsigned int, max_segment,
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PAGE_SIZE) >> PAGE_SHIFT;
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max_order = min(max_order, ilog2(max_segment));
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}
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}
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#endif
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gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
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if (IS_I965GM(i915) || IS_I965G(i915)) {
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/* 965gm cannot relocate objects above 4GiB. */
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gfp &= ~__GFP_HIGHMEM;
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gfp |= __GFP_DMA32;
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}
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create_st:
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st = kmalloc(sizeof(*st), GFP_KERNEL);
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if (!st)
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return ERR_PTR(-ENOMEM);
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npages = obj->base.size / PAGE_SIZE;
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if (sg_alloc_table(st, npages, GFP_KERNEL)) {
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kfree(st);
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return ERR_PTR(-ENOMEM);
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}
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sg = st->sgl;
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st->nents = 0;
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do {
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int order = min(fls(npages) - 1, max_order);
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struct page *page;
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do {
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page = alloc_pages(gfp | (order ? QUIET : 0), order);
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if (page)
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break;
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if (!order--)
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goto err;
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/* Limit subsequent allocations as well */
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max_order = order;
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} while (1);
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sg_set_page(sg, page, PAGE_SIZE << order, 0);
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st->nents++;
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npages -= 1 << order;
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if (!npages) {
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sg_mark_end(sg);
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break;
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}
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sg = __sg_next(sg);
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} while (1);
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if (i915_gem_gtt_prepare_pages(obj, st)) {
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/* Failed to dma-map try again with single page sg segments */
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if (get_order(st->sgl->length)) {
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internal_free_pages(st);
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max_order = 0;
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goto create_st;
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}
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goto err;
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}
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/* Mark the pages as dontneed whilst they are still pinned. As soon
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* as they are unpinned they are allowed to be reaped by the shrinker,
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* and the caller is expected to repopulate - the contents of this
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* object are only valid whilst active and pinned.
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*/
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obj->mm.madv = I915_MADV_DONTNEED;
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return st;
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err:
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sg_set_page(sg, NULL, 0, 0);
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sg_mark_end(sg);
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internal_free_pages(st);
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return ERR_PTR(-ENOMEM);
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}
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static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
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struct sg_table *pages)
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{
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i915_gem_gtt_finish_pages(obj, pages);
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internal_free_pages(pages);
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obj->mm.dirty = false;
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obj->mm.madv = I915_MADV_WILLNEED;
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}
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static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
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.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
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I915_GEM_OBJECT_IS_SHRINKABLE,
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.get_pages = i915_gem_object_get_pages_internal,
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.put_pages = i915_gem_object_put_pages_internal,
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};
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/**
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* Creates a new object that wraps some internal memory for private use.
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* This object is not backed by swappable storage, and as such its contents
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* are volatile and only valid whilst pinned. If the object is reaped by the
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* shrinker, its pages and data will be discarded. Equally, it is not a full
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* GEM object and so not valid for access from userspace. This makes it useful
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* for hardware interfaces like ringbuffers (which are pinned from the time
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* the request is written to the time the hardware stops accessing it), but
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* not for contexts (which need to be preserved when not active for later
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* reuse). Note that it is not cleared upon allocation.
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*/
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struct drm_i915_gem_object *
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i915_gem_object_create_internal(struct drm_i915_private *i915,
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phys_addr_t size)
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{
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struct drm_i915_gem_object *obj;
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unsigned int cache_level;
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GEM_BUG_ON(!size);
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GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
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if (overflows_type(size, obj->base.size))
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return ERR_PTR(-E2BIG);
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obj = i915_gem_object_alloc(i915);
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if (!obj)
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return ERR_PTR(-ENOMEM);
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drm_gem_private_object_init(&i915->drm, &obj->base, size);
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i915_gem_object_init(obj, &i915_gem_object_internal_ops);
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obj->base.read_domains = I915_GEM_DOMAIN_CPU;
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obj->base.write_domain = I915_GEM_DOMAIN_CPU;
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cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
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i915_gem_object_set_cache_coherency(obj, cache_level);
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return obj;
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}
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