From 24f8e00a8a2eae92491f8668939dbfdc123d6e75 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 22 Mar 2017 11:05:21 +0000
Subject: [PATCH] drm/i915: Prefer to report ENOMEM rather than incur the oom
for gfx allocations
Since gfx allocations tend to be large, unmovable and disposable, report
the allocation failure back to userspace as an ENOMEM rather than incur
the oomkiller. We have already tried to make room by purging our own
cached gfx objects, and the oomkiller doesn't attribute ownership of gfx
objects so will likely pick the wrong candidate. Instead, let userspace
see the ENOMEM.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322110521.29930-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index bb65072f688d..9d710bd8c6c9 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2321,7 +2321,7 @@ rebuild_st:
st->nents = 0;
for (i = 0; i < page_count; i++) {
page = shmem_read_mapping_page_gfp(mapping, i, gfp);
- if (IS_ERR(page)) {
+ if (unlikely(IS_ERR(page))) {
i915_gem_shrink(dev_priv,
page_count,
I915_SHRINK_BOUND |
@@ -2329,12 +2329,21 @@ rebuild_st:
I915_SHRINK_PURGEABLE);
page = shmem_read_mapping_page_gfp(mapping, i, gfp);
}
- if (IS_ERR(page)) {
+ if (unlikely(IS_ERR(page))) {
+ gfp_t reclaim;
+
/* We've tried hard to allocate the memory by reaping
* our own buffer, now let the real VM do its job and
* go down in flames if truly OOM.
+ *
+ * However, since graphics tend to be disposable,
+ * defer the oom here by reporting the ENOMEM back
+ * to userspace.
*/
- page = shmem_read_mapping_page(mapping, i);
+ reclaim = mapping_gfp_constraint(mapping, 0);
+ reclaim |= __GFP_NORETRY; /* reclaim, but no oom */
+
+ page = shmem_read_mapping_page_gfp(mapping, i, gfp);
if (IS_ERR(page)) {
ret = PTR_ERR(page);
goto err_sg;
--
2.49.0