[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. Change-Id: I5531c9337836e7d4a430df3f16dcc82888e8018c Signed-off-by: Alex Sierra <alex.sie...@amd.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 14 ++++++------- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 28 +++++++++++++++++++++++++- 2 files changed, 34 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index b999b67ff57a..b36daa6230fb 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -678,9 +678,9 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm, } } - mutex_lock(&vm->eviction_lock); + vm_eviction_lock(vm); vm->evicting = false; - mutex_unlock(&vm->eviction_lock); + vm_eviction_unlock(vm); return 0; } @@ -1559,7 +1559,7 @@ 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); + vm_eviction_lock(vm); if (vm->evicting) { r = -EBUSY; goto error_unlock; @@ -1576,7 +1576,7 @@ 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); + vm_eviction_unlock(vm); return r; } @@ -2537,18 +2537,18 @@ bool amdgpu_vm_evictable(struct amdgpu_bo *bo) return false; /* Try to block ongoing updates */ - if (!mutex_trylock(&bo_base->vm->eviction_lock)) + if (!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); + vm_eviction_unlock(bo_base->vm); return false; } bo_base->vm->evicting = true; - mutex_unlock(&bo_base->vm->eviction_lock); + 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 100547f094ff..d35aa76469ec 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h @@ -30,6 +30,7 @@ #include <drm/gpu_scheduler.h> #include <drm/drm_file.h> #include <drm/ttm/ttm_bo_driver.h> +#include <linux/sched/mm.h> #include "amdgpu_sync.h" #include "amdgpu_ring.h" @@ -242,9 +243,12 @@ 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; @@ -436,4 +440,26 @@ void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev, struct amdgpu_vm *vm); void amdgpu_vm_del_from_lru_notify(struct ttm_buffer_object *bo); +/* 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 vm_eviction_lock(struct amdgpu_vm *vm) +{ + mutex_lock(&vm->eviction_lock); + vm->saved_flags = memalloc_nofs_save(); +} +static inline int 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 vm_eviction_unlock(struct amdgpu_vm *vm) +{ + memalloc_nofs_restore(vm->saved_flags); + mutex_unlock(&vm->eviction_lock); +} #endif -- 2.17.1 _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx