From a269e44989f3e77fb2ebfb995b8d501924ed07e2 Mon Sep 17 00:00:00 2001 From: Alex Sierra Date: Tue, 17 Dec 2019 16:57:30 -0600 Subject: [PATCH] drm/amdgpu: Avoid reclaim fs while eviction lock MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [Why] Avoid reclaim filesystem while eviction lock is held called from MMU notifier. [How] Setting PF_MEMALLOC_NOFS flags while eviction mutex is locked. Using memalloc_nofs_save / memalloc_nofs_restore API. Signed-off-by: Alex Sierra Reviewed-by: Felix Kuehling Reviewed-by: Christian König Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 40 ++++++++++++++++++++++++++++------ drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 6 ++++- 2 files changed, 38 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 4dc75ed..d16231d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -83,6 +83,32 @@ struct amdgpu_prt_cb { }; /** + * vm eviction_lock can be taken in MMU notifiers. Make sure no reclaim-FS + * happens while holding this lock anywhere to prevent deadlocks when + * an MMU notifier runs in reclaim-FS context. + */ +static inline void amdgpu_vm_eviction_lock(struct amdgpu_vm *vm) +{ + mutex_lock(&vm->eviction_lock); + vm->saved_flags = memalloc_nofs_save(); +} + +static inline int amdgpu_vm_eviction_trylock(struct amdgpu_vm *vm) +{ + if (mutex_trylock(&vm->eviction_lock)) { + vm->saved_flags = memalloc_nofs_save(); + return 1; + } + return 0; +} + +static inline void amdgpu_vm_eviction_unlock(struct amdgpu_vm *vm) +{ + memalloc_nofs_restore(vm->saved_flags); + mutex_unlock(&vm->eviction_lock); +} + +/** * amdgpu_vm_level_shift - return the addr shift for each level * * @adev: amdgpu_device pointer @@ -678,9 +704,9 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm, } } - mutex_lock(&vm->eviction_lock); + amdgpu_vm_eviction_lock(vm); vm->evicting = false; - mutex_unlock(&vm->eviction_lock); + amdgpu_vm_eviction_unlock(vm); return 0; } @@ -1559,7 +1585,7 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev, if (!(flags & AMDGPU_PTE_VALID)) owner = AMDGPU_FENCE_OWNER_KFD; - mutex_lock(&vm->eviction_lock); + amdgpu_vm_eviction_lock(vm); if (vm->evicting) { r = -EBUSY; goto error_unlock; @@ -1576,7 +1602,7 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev, r = vm->update_funcs->commit(¶ms, fence); error_unlock: - mutex_unlock(&vm->eviction_lock); + amdgpu_vm_eviction_unlock(vm); return r; } @@ -2533,18 +2559,18 @@ bool amdgpu_vm_evictable(struct amdgpu_bo *bo) return false; /* Try to block ongoing updates */ - if (!mutex_trylock(&bo_base->vm->eviction_lock)) + if (!amdgpu_vm_eviction_trylock(bo_base->vm)) return false; /* Don't evict VM page tables while they are updated */ if (!dma_fence_is_signaled(bo_base->vm->last_direct) || !dma_fence_is_signaled(bo_base->vm->last_delayed)) { - mutex_unlock(&bo_base->vm->eviction_lock); + amdgpu_vm_eviction_unlock(bo_base->vm); return false; } bo_base->vm->evicting = true; - mutex_unlock(&bo_base->vm->eviction_lock); + amdgpu_vm_eviction_unlock(bo_base->vm); return true; } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h index fade4f4..b4640ab 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h @@ -30,6 +30,7 @@ #include #include #include +#include #include "amdgpu_sync.h" #include "amdgpu_ring.h" @@ -239,9 +240,12 @@ struct amdgpu_vm { /* tree of virtual addresses mapped */ struct rb_root_cached va; - /* Lock to prevent eviction while we are updating page tables */ + /* Lock to prevent eviction while we are updating page tables + * use vm_eviction_lock/unlock(vm) + */ struct mutex eviction_lock; bool evicting; + unsigned int saved_flags; /* BOs who needs a validation */ struct list_head evicted; -- 2.7.4