Re: [PATCH 2/2] drm/ttm: add ttm page_flags TTM_PAGE_FLAG_PAGEFAULT

On 2018年01月29日 16:31, Roger He wrote:

to indicate whether we are serving for page fault routine when in ttm_mem_global_reserve.

for ttm_mem_global_reserve if in page fault routine, allow success always. because page fault routing already grabbed system memory successfully and allow this exception is harmless. Otherwise, it will trigger OOM killer.

v2: add new page flag TTM_PAGE_FLAG_PAGEFAULT rather than using struct ttm_operation_ctx

Signed-off-by: Roger He Hongbo.He@amd.com

drivers/gpu/drm/ttm/ttm_bo_vm.c | 6 ++++-- drivers/gpu/drm/ttm/ttm_memory.c | 27 +++++++++++++++++++-------- drivers/gpu/drm/ttm/ttm_page_alloc.c | 5 ++++- drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 9 ++++++--- drivers/gpu/drm/ttm/ttm_tt.c | 2 +- include/drm/ttm/ttm_bo_driver.h | 1 + include/drm/ttm/ttm_memory.h | 3 ++- 7 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 08a3c32..1aee124 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -235,9 +235,11 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) ttm = bo->ttm; cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, cvma.vm_page_prot);

• ttm->page_flags |= TTM_PAGE_FLAG_PAGEFAULT;
  

  /* Allocate all page at once, most common usage */

• if (ttm->bdev->driver->ttm_tt_populate(ttm, &ctx)) {
  

• ret = ttm->bdev->driver->ttm_tt_populate(ttm, &ctx);
  

• ttm->page_flags &= ~TTM_PAGE_FLAG_PAGEFAULT;
  

• if (ret) {
  retval = VM_FAULT_OOM;
  goto out_io_unlock;
  

  }

diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c index 06024ba..d0312a7 100644 --- a/drivers/gpu/drm/ttm/ttm_memory.c +++ b/drivers/gpu/drm/ttm/ttm_memory.c @@ -473,7 +473,8 @@ EXPORT_SYMBOL(ttm_mem_global_free);

static int ttm_mem_global_reserve(struct ttm_mem_global *glob, struct ttm_mem_zone *single_zone,

• 		  uint64_t amount, bool reserve)
  

• 		  uint64_t amount, bool reserve,
  

• 		  bool in_pagefault)
  

  { uint64_t swap_glob_mem, max_swap_cache; uint64_t limit, total_used_mem;

@@ -485,6 +486,13 @@ static int ttm_mem_global_reserve(struct ttm_mem_global *glob, max_swap_cache = (get_total_swap_pages() >> 1) << PAGE_SHIFT;

spin_lock(&glob->lock);

• /*

• * if in page_fault allow reserve successfully anyway since it
  

• * already allocated system pages. Otherwise it will trigger OOM
  

• */
  

• if (in_pagefault)

• goto reserve_direct;
  

• for (i = 0; i < glob->num_zones; ++i) { zone = glob->zones[i]; if (single_zone && zone != single_zone)

@@ -499,6 +507,7 @@ static int ttm_mem_global_reserve(struct ttm_mem_global *glob, goto out_unlock; }

+reserve_direct: if (reserve) { for (i = 0; i < glob->num_zones; ++i) { zone = glob->zones[i]; @@ -520,13 +529,13 @@ static int ttm_mem_global_reserve(struct ttm_mem_global *glob, static int ttm_mem_global_alloc_zone(struct ttm_mem_global *glob, struct ttm_mem_zone *single_zone, uint64_t memory,

• 		     struct ttm_operation_ctx *ctx)
  

• 		     struct ttm_operation_ctx *ctx,
  

• 		     bool in_pagefault)
  

  { int count = TTM_MEMORY_ALLOC_RETRIES;

• while (unlikely(ttm_mem_global_reserve(glob,

• 			       single_zone,
  

• 			       memory, true)
  

• while (unlikely(ttm_mem_global_reserve(glob, single_zone, memory,

• 			       true, in_pagefault)
  != 0)) {
  

  if (ctx->no_wait_gpu) return -ENOMEM;

@@ -546,13 +555,14 @@ int ttm_mem_global_alloc(struct ttm_mem_global *glob, uint64_t memory, * all zones. */

• return ttm_mem_global_alloc_zone(glob, NULL, memory, ctx);

• return ttm_mem_global_alloc_zone(glob, NULL, memory, ctx, false); } EXPORT_SYMBOL(ttm_mem_global_alloc);

  int ttm_mem_global_alloc_page(struct ttm_mem_global *glob, struct page *page, uint64_t size,

• 	      struct ttm_operation_ctx *ctx)
  

• 	      struct ttm_operation_ctx *ctx,
  

• 	      bool in_pagefault)
  

  { struct ttm_mem_zone *zone = NULL;

@@ -568,7 +578,8 @@ int ttm_mem_global_alloc_page(struct ttm_mem_global *glob, if (glob->zone_dma32 && page_to_pfn(page) > 0x00100000UL) zone = glob->zone_kernel; #endif

• return ttm_mem_global_alloc_zone(glob, zone, size, ctx);

• return ttm_mem_global_alloc_zone(glob, zone, size,

• 			 ctx, in_pagefault);
  

  }

  void ttm_mem_global_free_page(struct ttm_mem_global *glob, struct page *page,

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c index 5edcd89..39b184f 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c @@ -1094,6 +1094,7 @@ ttm_pool_unpopulate_helper(struct ttm_tt *ttm, unsigned mem_count_update) int ttm_pool_populate(struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) { struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;

• bool in_pagefault; unsigned i; int ret;

@@ -1107,9 +1108,11 @@ int ttm_pool_populate(struct ttm_tt *ttm, struct ttm_operation_ctx *ctx) return ret; }

• in_pagefault = ttm->page_flags | TTM_PAGE_FLAG_PAGEFAULT;

I guess you want to write as "in_pagefault = ttm->page_flags & TTM_PAGE_FLAG_PAGEFAULT; ".

for (i = 0; i < ttm->num_pages; ++i) { ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],

• 				PAGE_SIZE, ctx);
  

• 				PAGE_SIZE, ctx,
  

• 				in_pagefault);
  

  if (unlikely(ret != 0)) { ttm_pool_unpopulate_helper(ttm, i); return -ENOMEM;

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c index 9e90d0e..77dd167 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c @@ -939,6 +939,7 @@ int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev, struct dma_pool *pool; struct dma_page *d_page; enum pool_type type;

• bool in_pagefault; unsigned i; int ret;

@@ -948,8 +949,8 @@ int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev, INIT_LIST_HEAD(&ttm_dma->pages_list); i = 0;

• in_pagefault = ttm_dma->ttm.page_flags | TTM_PAGE_FLAG_PAGEFAULT;

same above, should be "in_pagefault = ttm->page_flags & TTM_PAGE_FLAG_PAGEFAULT; ".

Regards, David Zhou

type = ttm_to_type(ttm->page_flags, ttm->caching_state);

• #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (ttm->page_flags & TTM_PAGE_FLAG_DMA32) goto skip_huge;

@@ -971,7 +972,8 @@ int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev, break;

ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],

• 				pool->size, ctx);
  

• 				pool->size, ctx,
  

• 				in_pagefault);
  

  if (unlikely(ret != 0)) { ttm_dma_unpopulate(ttm_dma, dev); return -ENOMEM;

@@ -1008,7 +1010,8 @@ int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev, }

ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],

• 				pool->size, ctx);
  

• 				pool->size, ctx,
  

• 				in_pagefault);
  

  if (unlikely(ret != 0)) { ttm_dma_unpopulate(ttm_dma, dev); return -ENOMEM;

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 395cac0..c36db66 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -386,7 +386,7 @@ int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage) ttm->page_flags |= TTM_PAGE_FLAG_PERSISTENT_SWAP; else atomic64_add_return(ttm->num_pages << PAGE_SHIFT,

• 	    &ttm->glob->mem_glob->swap_glob_mem);
  

• 		    &ttm->glob->mem_glob->swap_glob_mem);
  
  

  return 0; out_err:

diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index 9b417eb..8f68781 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -87,6 +87,7 @@ struct ttm_backend_func { #define TTM_PAGE_FLAG_DMA32 (1 << 7) #define TTM_PAGE_FLAG_SG (1 << 8) #define TTM_PAGE_FLAG_NO_RETRY (1 << 9) +#define TTM_PAGE_FLAG_PAGEFAULT (1 << 10)

enum ttm_caching_state { tt_uncached, diff --git a/include/drm/ttm/ttm_memory.h b/include/drm/ttm/ttm_memory.h index a273581..b801010 100644 --- a/include/drm/ttm/ttm_memory.h +++ b/include/drm/ttm/ttm_memory.h @@ -87,7 +87,8 @@ extern void ttm_mem_global_free(struct ttm_mem_global *glob, uint64_t amount); extern int ttm_mem_global_alloc_page(struct ttm_mem_global *glob, struct page *page, uint64_t size,

• 		     struct ttm_operation_ctx *ctx);
  

• 		     struct ttm_operation_ctx *ctx,
  

• 		     bool in_pagefault);
  

  extern void ttm_mem_global_free_page(struct ttm_mem_global *glob, struct page *page, uint64_t size); extern size_t ttm_round_pot(size_t size);