From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@amd.com>
Date: Wed, 25 Apr 2018 17:32:10 +0200
Subject: drm/ttm: Use GFP_TRANSHUGE_LIGHT for allocating huge pages
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Git-commit: da291320baec914f0bb4e65a9dccb86bd6c728f2
Patch-mainline: v4.17-rc5
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

GFP_TRANSHUGE tries very hard to allocate huge pages, which can result
in long delays with high memory pressure. I have observed firefox
freezing for up to around a minute due to this while restic was taking
a full system backup.

Since we don't really need huge pages, use GFP_TRANSHUGE_LIGHT |
__GFP_NORETRY instead, in order to fail quickly when there are no huge
pages available.

Set __GFP_KSWAPD_RECLAIM as well, in order for huge pages to be freed
up in the background if necessary.

With these changes, I'm no longer seeing freezes during a restic backup.

Cc: stable@vger.kernel.org
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/ttm/ttm_page_alloc.c     |   11 ++++++++---
 drivers/gpu/drm/ttm/ttm_page_alloc_dma.c |    3 ++-
 2 files changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -910,7 +910,8 @@ static int ttm_get_pages(struct page **p
 			while (npages >= HPAGE_PMD_NR) {
 				gfp_t huge_flags = gfp_flags;
 
-				huge_flags |= GFP_TRANSHUGE;
+				huge_flags |= GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
+					__GFP_KSWAPD_RECLAIM;
 				huge_flags &= ~__GFP_MOVABLE;
 				huge_flags &= ~__GFP_COMP;
 				p = alloc_pages(huge_flags, HPAGE_PMD_ORDER);
@@ -1027,11 +1028,15 @@ int ttm_page_alloc_init(struct ttm_mem_g
 				  GFP_USER | GFP_DMA32, "uc dma", 0);
 
 	ttm_page_pool_init_locked(&_manager->wc_pool_huge,
-				  GFP_TRANSHUGE	& ~(__GFP_MOVABLE | __GFP_COMP),
+				  (GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
+				   __GFP_KSWAPD_RECLAIM) &
+				  ~(__GFP_MOVABLE | __GFP_COMP),
 				  "wc huge", order);
 
 	ttm_page_pool_init_locked(&_manager->uc_pool_huge,
-				  GFP_TRANSHUGE	& ~(__GFP_MOVABLE | __GFP_COMP)
+				  (GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
+				   __GFP_KSWAPD_RECLAIM) &
+				  ~(__GFP_MOVABLE | __GFP_COMP)
 				  , "uc huge", order);
 
 	_manager->options.max_size = max_pages;
--- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
@@ -910,7 +910,8 @@ static gfp_t ttm_dma_pool_gfp_flags(stru
 		gfp_flags |= __GFP_ZERO;
 
 	if (huge) {
-		gfp_flags |= GFP_TRANSHUGE;
+		gfp_flags |= GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
+			__GFP_KSWAPD_RECLAIM;
 		gfp_flags &= ~__GFP_MOVABLE;
 		gfp_flags &= ~__GFP_COMP;
 	}