Let drm(4) allocate memory without constraints if the hardware supports

64-bit DMA.  Should reduce the pressure on DMA-reachable memory, which is
important since there are still cases where the pagedaemon ends up being
triggered continuously if we run out of DMA-reachable memory but have
plenty of memory left.

ok jsg@

3 files changed, 27 insertions, 17 deletions

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index f7a961c083d..0b86912cb72 100644
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: drm_linux.c,v 1.37 2019/06/04 12:08:22 jsg Exp $	*/
+/*	$OpenBSD: drm_linux.c,v 1.38 2019/06/09 12:58:30 kettenis Exp $	*/
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -293,16 +293,19 @@ struct vm_page *
 alloc_pages(unsigned int gfp_mask, unsigned int order)
 {
 	int flags = (gfp_mask & M_NOWAIT) ? UVM_PLA_NOWAIT : UVM_PLA_WAITOK;
+	struct uvm_constraint_range *constraint = &no_constraint;
 	struct pglist mlist;
 
 	if (gfp_mask & M_CANFAIL)
 		flags |= UVM_PLA_FAILOK;
 	if (gfp_mask & M_ZERO)
 		flags |= UVM_PLA_ZERO;
+	if (gfp_mask & __GFP_DMA32)
+		constraint = &dma_constraint;
 
 	TAILQ_INIT(&mlist);
-	if (uvm_pglistalloc(PAGE_SIZE << order, dma_constraint.ucr_low,
-	    dma_constraint.ucr_high, PAGE_SIZE, 0, &mlist, 1, flags))
+	if (uvm_pglistalloc(PAGE_SIZE << order, constraint->ucr_low,
+	    constraint->ucr_high, PAGE_SIZE, 0, &mlist, 1, flags))
 		return NULL;
 	return TAILQ_FIRST(&mlist);
 }
diff --git a/sys/dev/pci/drm/include/linux/gfp.h b/sys/dev/pci/drm/include/linux/gfp.h
index d3dd930b285..dcffa2ef49d 100644
--- a/sys/dev/pci/drm/include/linux/gfp.h
+++ b/sys/dev/pci/drm/include/linux/gfp.h
@@ -7,24 +7,25 @@
 #include <sys/malloc.h>
 #include <uvm/uvm_extern.h>
 
-#define GFP_ATOMIC	M_NOWAIT
-#define GFP_NOWAIT	M_NOWAIT
-#define GFP_KERNEL	(M_WAITOK | M_CANFAIL)
-#define GFP_USER	(M_WAITOK | M_CANFAIL)
-#define GFP_TEMPORARY	(M_WAITOK | M_CANFAIL)
-#define GFP_HIGHUSER	0
-#define GFP_DMA32	0
-#define __GFP_NOWARN	0
-#define __GFP_NORETRY	0
-#define __GFP_ZERO	M_ZERO
+#define __GFP_ZERO		M_ZERO
+#define __GFP_DMA32		0x00010000
+#define __GFP_NOWARN		0
+#define __GFP_NORETRY		0
 #define __GFP_RETRY_MAYFAIL	0
 #define __GFP_MOVABLE		0
 #define __GFP_COMP		0
-#define GFP_TRANSHUGE_LIGHT	0
 #define __GFP_KSWAPD_RECLAIM	0
 #define __GFP_HIGHMEM		0
 #define __GFP_RECLAIMABLE	0
-#define __GFP_DMA32		0
+
+#define GFP_ATOMIC		M_NOWAIT
+#define GFP_NOWAIT		M_NOWAIT
+#define GFP_KERNEL		(M_WAITOK | M_CANFAIL)
+#define GFP_USER		(M_WAITOK | M_CANFAIL)
+#define GFP_TEMPORARY		(M_WAITOK | M_CANFAIL)
+#define GFP_HIGHUSER		0
+#define GFP_DMA32		__GFP_DMA32
+#define GFP_TRANSHUGE_LIGHT	0
 
 static inline bool
 gfpflags_allow_blocking(const unsigned int flags)
diff --git a/sys/dev/pci/drm/ttm/ttm_tt.c b/sys/dev/pci/drm/ttm/ttm_tt.c
index 4acb4ce5052..ece237259d8 100644
--- a/sys/dev/pci/drm/ttm/ttm_tt.c
+++ b/sys/dev/pci/drm/ttm/ttm_tt.c
@@ -261,6 +261,7 @@ int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
 		    uint32_t page_flags)
 {
 	struct ttm_tt *ttm = &ttm_dma->ttm;
+	int flags = BUS_DMA_WAITOK;
 
 	ttm_tt_init_fields(ttm, bo, page_flags);
 
@@ -276,8 +277,10 @@ int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
 
 	ttm_dma->dmat = bo->bdev->dmat;
 
+	if ((page_flags & TTM_PAGE_FLAG_DMA32) == 0)
+		flags |= BUS_DMA_64BIT;
 	if (bus_dmamap_create(ttm_dma->dmat, ttm->num_pages << PAGE_SHIFT,
-	    ttm->num_pages, ttm->num_pages << PAGE_SHIFT, 0, BUS_DMA_WAITOK,
+	    ttm->num_pages, ttm->num_pages << PAGE_SHIFT, 0, flags,
 	    &ttm_dma->map)) {
 		free(ttm_dma->segs, M_DRM, 0);
 		ttm_tt_destroy(ttm);
@@ -293,6 +296,7 @@ int ttm_sg_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
 		   uint32_t page_flags)
 {
 	struct ttm_tt *ttm = &ttm_dma->ttm;
+	int flags = BUS_DMA_WAITOK;
 	int ret;
 
 	ttm_tt_init_fields(ttm, bo, page_flags);
@@ -313,8 +317,10 @@ int ttm_sg_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_buffer_object *bo,
 
 	ttm_dma->dmat = bo->bdev->dmat;
 
+	if ((page_flags & TTM_PAGE_FLAG_DMA32) == 0)
+		flags |= BUS_DMA_64BIT;
 	if (bus_dmamap_create(ttm_dma->dmat, ttm->num_pages << PAGE_SHIFT,
-	    ttm->num_pages, ttm->num_pages << PAGE_SHIFT, 0, BUS_DMA_WAITOK,
+	    ttm->num_pages, ttm->num_pages << PAGE_SHIFT, 0, flags,
 	    &ttm_dma->map)) {
 		free(ttm_dma->segs, M_DRM, 0);
 		ttm_tt_destroy(ttm);