On Wed, Jun 26, 2024 at 05:36:43PM +0200, Nirmoy Das wrote: > Hi Rodrigo, > > On 6/26/2024 5:24 PM, Rodrigo Vivi wrote: > > On Wed, Jun 26, 2024 at 04:33:18PM +0200, Nirmoy Das wrote: > > >We report object allocation failures to userspace with ENOMEM > >so add __GFP_NOWARN to remove superfluous oom warnings. > > >Closes: [1]https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4936 > >Cc: Andi Shyti [2]<andi.shyti@xxxxxxxxxxxxxxx> > >Signed-off-by: Nirmoy Das [3]<nirmoy.das@xxxxxxxxx> > >--- > > drivers/gpu/drm/i915/i915_scatterlist.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > >diff --git a/drivers/gpu/drm/i915/i915_scatterlist.c b/drivers/gpu/drm/i915/i915_scatterlist.c > >index e93d2538f298..4d830740946d 100644 > >--- a/drivers/gpu/drm/i915/i915_scatterlist.c > >+++ b/drivers/gpu/drm/i915/i915_scatterlist.c > >@@ -90,7 +90,7 @@ struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node, > > > > GEM_BUG_ON(!max_segment); > > > >- rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL); > >+ rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL | __GFP_NOWARN); > > if (!rsgt) > > return ERR_PTR(-ENOMEM); > > is it really safe? > I don't believe we can guarantee a good fallback plan here if allocation fails. > __i915_refct_sgt_init > might end up in a null dereference, no?! > > Kernel is now returning ENOMEM and also throwing a oom warning stack. > With __GFP_NOWARN > > the oom warning stack won't be there in the dmesg but userspace will still > get ENOMEM as expected. doh! I had missunderstand the flag. Thanks for the confirmation. Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> BTW, what email clients are you using recently? it is hard to parse your responses lately. Please check if it is really sending/replying as text-only mode. > > Let me know if got your question correctly. > > Regards, > > Nirmoy > > > > > > >@@ -104,7 +104,7 @@ struct i915_refct_sgt *i915_rsgt_from_mm_node(const struct drm_mm_node *node, > > } > > > > if (sg_alloc_table(st, DIV_ROUND_UP_ULL(node->size, segment_pages), > >- GFP_KERNEL)) { > >+ GFP_KERNEL | __GFP_NOWARN)) { > > i915_refct_sgt_put(rsgt); > > return ERR_PTR(-ENOMEM); > > } > >@@ -178,7 +178,7 @@ struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res, > > GEM_BUG_ON(list_empty(blocks)); > > GEM_BUG_ON(!max_segment); > > > >- rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL); > >+ rsgt = kmalloc(sizeof(*rsgt), GFP_KERNEL | __GFP_NOWARN); > > if (!rsgt) > > return ERR_PTR(-ENOMEM); > > > >@@ -190,7 +190,7 @@ struct i915_refct_sgt *i915_rsgt_from_buddy_resource(struct ttm_resource *res, > > return ERR_PTR(-E2BIG); > > } > > > >- if (sg_alloc_table(st, PFN_UP(res->size), GFP_KERNEL)) { > >+ if (sg_alloc_table(st, PFN_UP(res->size), GFP_KERNEL | __GFP_NOWARN)) { > > i915_refct_sgt_put(rsgt); > > return ERR_PTR(-ENOMEM); > > } > >-- > >2.42.0 > > References > > Visible links > 1. https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/4936 > 2. mailto:andi.shyti@xxxxxxxxxxxxxxx > 3. mailto:nirmoy.das@xxxxxxxxx
