The gpu coredump typically takes place in a dma_fence signalling
critical path, and hence can't use GFP_KERNEL allocations, as that
means we might hit deadlocks under memory pressure. However
changing to __GFP_KSWAPD_RECLAIM which will be done in an upcoming
patch will instead mean a lower chance of the allocation succeeding.
In particular large contigous allocations like the coredump page
vector.
Remove the page vector in favor of a linked list of single pages.
Use the page lru list head as the list link, as the page owner is
allowed to do that.
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gpu_error.c | 50 +++++++++++++++------------
drivers/gpu/drm/i915/i915_gpu_error.h | 4 +--
2 files changed, 28 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 2a2d7643b551..14de64282697 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -275,16 +275,16 @@ static bool compress_start(struct i915_vma_compress *c)
static void *compress_next_page(struct i915_vma_compress *c,
struct i915_vma_coredump *dst)
{
- void *page;
+ void *page_addr;
+ struct page *page;
- if (dst->page_count >= dst->num_pages)
- return ERR_PTR(-ENOSPC);
-
- page = pool_alloc(&c->pool, ALLOW_FAIL);
- if (!page)
+ page_addr = pool_alloc(&c->pool, ALLOW_FAIL);
+ if (!page_addr)
return ERR_PTR(-ENOMEM);
- return dst->pages[dst->page_count++] = page;
+ page = virt_to_page(page_addr);
+ list_add_tail(&page->lru, &dst->page_list);
+ return page_addr;
}
static int compress_page(struct i915_vma_compress *c,
@@ -397,7 +397,7 @@ static int compress_page(struct i915_vma_compress *c,
if (!(wc && i915_memcpy_from_wc(ptr, src, PAGE_SIZE)))
memcpy(ptr, src, PAGE_SIZE);
- dst->pages[dst->page_count++] = ptr;
+ list_add_tail(&virt_to_page(ptr)->lru, &dst->page_list);
cond_resched();
return 0;
@@ -614,7 +614,7 @@ static void print_error_vma(struct drm_i915_error_state_buf *m,
const struct i915_vma_coredump *vma)
{
char out[ASCII85_BUFSZ];
- int page;
+ struct page *page;
if (!vma)
return;
@@ -628,16 +628,17 @@ static void print_error_vma(struct drm_i915_error_state_buf *m,
err_printf(m, "gtt_page_sizes = 0x%08x\n", vma->gtt_page_sizes);
err_compression_marker(m);
- for (page = 0; page < vma->page_count; page++) {
+ list_for_each_entry(page, &vma->page_list, lru) {
int i, len;
+ const u32 *addr = page_address(page);
len = PAGE_SIZE;
- if (page == vma->page_count - 1)
+ if (page == list_last_entry(&vma->page_list, typeof(*page), lru))
len -= vma->unused;
len = ascii85_encode_len(len);
for (i = 0; i < len; i++)
- err_puts(m, ascii85_encode(vma->pages[page][i], out));
+ err_puts(m, ascii85_encode(addr[i], out));
}
err_puts(m, "\n");
}
@@ -946,10 +947,12 @@ static void i915_vma_coredump_free(struct i915_vma_coredump *vma)
{
while (vma) {
struct i915_vma_coredump *next = vma->next;
- int page;
+ struct page *page, *n;
- for (page = 0; page < vma->page_count; page++)
- free_page((unsigned long)vma->pages[page]);
+ list_for_each_entry_safe(page, n, &vma->page_list, lru) {
+ list_del_init(&page->lru);
+ __free_page(page);
+ }
kfree(vma);
vma = next;
@@ -1016,7 +1019,6 @@ i915_vma_coredump_create(const struct intel_gt *gt,
struct i915_ggtt *ggtt = gt->ggtt;
const u64 slot = ggtt->error_capture.start;
struct i915_vma_coredump *dst;
- unsigned long num_pages;
struct sgt_iter iter;
int ret;
@@ -1025,9 +1027,7 @@ i915_vma_coredump_create(const struct intel_gt *gt,
if (!vma || !vma->pages || !compress)
return NULL;
- num_pages = min_t(u64, vma->size, vma->obj->base.size) >> PAGE_SHIFT;
- num_pages = DIV_ROUND_UP(10 * num_pages, 8); /* worstcase zlib growth */
- dst = kmalloc(sizeof(*dst) + num_pages * sizeof(u32 *), ALLOW_FAIL);
+ dst = kmalloc(sizeof(*dst), ALLOW_FAIL);
if (!dst)
return NULL;
@@ -1036,14 +1036,13 @@ i915_vma_coredump_create(const struct intel_gt *gt,
return NULL;
}
+ INIT_LIST_HEAD(&dst->page_list);
strcpy(dst->name, name);
dst->next = NULL;
dst->gtt_offset = vma->node.start;
dst->gtt_size = vma->node.size;
dst->gtt_page_sizes = vma->page_sizes.gtt;
- dst->num_pages = num_pages;
- dst->page_count = 0;
dst->unused = 0;
ret = -EINVAL;
@@ -1106,8 +1105,13 @@ i915_vma_coredump_create(const struct intel_gt *gt,
}
if (ret || compress_flush(compress, dst)) {
- while (dst->page_count--)
- pool_free(&compress->pool, dst->pages[dst->page_count]);
+ struct page *page, *n;
+
+ list_for_each_entry_safe_reverse(page, n, &dst->page_list, lru) {
+ list_del_init(&page->lru);
+ pool_free(&compress->pool, page_address(page));
+ }
+
kfree(dst);
dst = NULL;
}
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index b98d8cdbe4f2..5aedf5129814 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -39,10 +39,8 @@ struct i915_vma_coredump {
u64 gtt_size;
u32 gtt_page_sizes;
- int num_pages;
- int page_count;
int unused;
- u32 *pages[];
+ struct list_head page_list;
};
struct i915_request_coredump {
--
2.31.1
