I fixed 2 regressions and latest code, applied your patch on top and passed libdrm tests on Vega 10. You can pickup those 2 patches and try too if you have time. In any case -

Reviewed-and-tested-by: Andrey Grodzovsky <andrey.grodzov...@amd.com>

Andrey

On 2021-09-15 2:37 a.m., xinhui pan wrote:
We hit soft hang while doing memory pressure test on one numa system.
After a qucik look, this is because kfd invalid/valid userptr memory
frequently with process_info lock hold.
Looks like update page table mapping use too much cpu time.

perf top says below,
75.81%  [kernel]       [k] __srcu_read_unlock
  6.19%  [amdgpu]       [k] amdgpu_gmc_set_pte_pde
  3.56%  [kernel]       [k] __srcu_read_lock
  2.20%  [amdgpu]       [k] amdgpu_vm_cpu_update
  2.20%  [kernel]       [k] __sg_page_iter_dma_next
  2.15%  [drm]          [k] drm_dev_enter
  1.70%  [drm]          [k] drm_prime_sg_to_dma_addr_array
  1.18%  [kernel]       [k] __sg_alloc_table_from_pages
  1.09%  [drm]          [k] drm_dev_exit

So move drm_dev_enter/exit outside gmc code, instead let caller do it.
They are gart_unbind, gart_map, vm_clear_bo, vm_update_pdes and
gmc_init_pdb0. vm_bo_update_mapping already calls it.

Signed-off-by: xinhui pan <xinhui....@amd.com>
---
change from v1:
add enter/exit in more gmc_set_pte_pde callers
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 11 ++++++++++
  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c  | 11 +++++-----
  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c   | 28 +++++++++++++++++-------
  3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
index 76efd5f8950f..d7e4f4660acf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
@@ -34,6 +34,7 @@
  #include <asm/set_memory.h>
  #endif
  #include "amdgpu.h"
+#include <drm/drm_drv.h>
/*
   * GART
@@ -230,12 +231,16 @@ int amdgpu_gart_unbind(struct amdgpu_device *adev, 
uint64_t offset,
        u64 page_base;
        /* Starting from VEGA10, system bit must be 0 to mean invalid. */
        uint64_t flags = 0;
+       int idx;
if (!adev->gart.ready) {
                WARN(1, "trying to unbind memory from uninitialized GART !\n");
                return -EINVAL;
        }
+ if (!drm_dev_enter(&adev->ddev, &idx))
+               return 0;
+
        t = offset / AMDGPU_GPU_PAGE_SIZE;
        p = t / AMDGPU_GPU_PAGES_IN_CPU_PAGE;
        for (i = 0; i < pages; i++, p++) {
@@ -254,6 +259,7 @@ int amdgpu_gart_unbind(struct amdgpu_device *adev, uint64_t 
offset,
        for (i = 0; i < adev->num_vmhubs; i++)
                amdgpu_gmc_flush_gpu_tlb(adev, 0, i, 0);
+ drm_dev_exit(idx);
        return 0;
  }
@@ -276,12 +282,16 @@ int amdgpu_gart_map(struct amdgpu_device *adev, uint64_t offset,
  {
        uint64_t page_base;
        unsigned i, j, t;
+       int idx;
if (!adev->gart.ready) {
                WARN(1, "trying to bind memory to uninitialized GART !\n");
                return -EINVAL;
        }
+ if (!drm_dev_enter(&adev->ddev, &idx))
+               return 0;
+
        t = offset / AMDGPU_GPU_PAGE_SIZE;
for (i = 0; i < pages; i++) {
@@ -291,6 +301,7 @@ int amdgpu_gart_map(struct amdgpu_device *adev, uint64_t 
offset,
                        page_base += AMDGPU_GPU_PAGE_SIZE;
                }
        }
+       drm_dev_exit(idx);
        return 0;
  }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
index 54f059501a33..1427fd70310c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -153,10 +153,6 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device *adev, 
void *cpu_pt_addr,
  {
        void __iomem *ptr = (void *)cpu_pt_addr;
        uint64_t value;
-       int idx;
-
-       if (!drm_dev_enter(&adev->ddev, &idx))
-               return 0;
/*
         * The following is for PTE only. GART does not have PDEs.
@@ -165,8 +161,6 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device *adev, void 
*cpu_pt_addr,
        value |= flags;
        writeq(value, ptr + (gpu_page_idx * 8));
- drm_dev_exit(idx);
-
        return 0;
  }
@@ -752,6 +746,10 @@ void amdgpu_gmc_init_pdb0(struct amdgpu_device *adev)
                adev->gmc.xgmi.physical_node_id * 
adev->gmc.xgmi.node_segment_size;
        u64 vram_end = vram_addr + vram_size;
        u64 gart_ptb_gpu_pa = amdgpu_gmc_vram_pa(adev, adev->gart.bo);
+       int idx;
+
+       if (!drm_dev_enter(&adev->ddev, &idx))
+               return;
flags |= AMDGPU_PTE_VALID | AMDGPU_PTE_READABLE;
        flags |= AMDGPU_PTE_WRITEABLE;
@@ -773,6 +771,7 @@ void amdgpu_gmc_init_pdb0(struct amdgpu_device *adev)
        flags |= AMDGPU_PDE_BFS(0) | AMDGPU_PTE_SNOOPED;
        /* Requires gart_ptb_gpu_pa to be 4K aligned */
        amdgpu_gmc_set_pte_pde(adev, adev->gmc.ptr_pdb0, i, gart_ptb_gpu_pa, 
flags);
+       drm_dev_exit(idx);
  }
/**
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 0126ece898da..daa16d2f89da 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -800,7 +800,7 @@ static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
        struct amdgpu_bo *bo = &vmbo->bo;
        unsigned entries, ats_entries;
        uint64_t addr;
-       int r;
+       int r, idx;
/* Figure out our place in the hierarchy */
        if (ancestor->parent) {
@@ -845,9 +845,12 @@ static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
                        return r;
        }
+ if (!drm_dev_enter(&adev->ddev, &idx))
+               return -ENODEV;
+
        r = vm->update_funcs->map_table(vmbo);
        if (r)
-               return r;
+               goto exit;
memset(&params, 0, sizeof(params));
        params.adev = adev;
@@ -856,7 +859,7 @@ static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
r = vm->update_funcs->prepare(&params, NULL, AMDGPU_SYNC_EXPLICIT);
        if (r)
-               return r;
+               goto exit;
addr = 0;
        if (ats_entries) {
@@ -872,7 +875,7 @@ static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
                r = vm->update_funcs->update(&params, vmbo, addr, 0, 
ats_entries,
                                             value, flags);
                if (r)
-                       return r;
+                       goto exit;
addr += ats_entries * 8;
        }
@@ -895,10 +898,13 @@ static int amdgpu_vm_clear_bo(struct amdgpu_device *adev,
                r = vm->update_funcs->update(&params, vmbo, addr, 0, entries,
                                             value, flags);
                if (r)
-                       return r;
+                       goto exit;
        }
- return vm->update_funcs->commit(&params, NULL);
+       r = vm->update_funcs->commit(&params, NULL);
+exit:
+       drm_dev_exit(idx);
+       return r;
  }
/**
@@ -1384,11 +1390,14 @@ int amdgpu_vm_update_pdes(struct amdgpu_device *adev,
                          struct amdgpu_vm *vm, bool immediate)
  {
        struct amdgpu_vm_update_params params;
-       int r;
+       int r, idx;
if (list_empty(&vm->relocated))
                return 0;
+ if (!drm_dev_enter(&adev->ddev, &idx))
+               return -ENODEV;
+
        memset(&params, 0, sizeof(params));
        params.adev = adev;
        params.vm = vm;
@@ -1396,7 +1405,7 @@ int amdgpu_vm_update_pdes(struct amdgpu_device *adev,
r = vm->update_funcs->prepare(&params, NULL, AMDGPU_SYNC_EXPLICIT);
        if (r)
-               return r;
+               goto exit;
while (!list_empty(&vm->relocated)) {
                struct amdgpu_vm_bo_base *entry;
@@ -1414,10 +1423,13 @@ int amdgpu_vm_update_pdes(struct amdgpu_device *adev,
        r = vm->update_funcs->commit(&params, &vm->last_update);
        if (r)
                goto error;
+       drm_dev_exit(idx);
        return 0;
error:
        amdgpu_vm_invalidate_pds(adev, vm);
+exit:
+       drm_dev_exit(idx);
        return r;
  }

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