From 34f89ac8e66cd5121fb05c765acc3c67ddbef7a0 Mon Sep 17 00:00:00 2001 From: Niranjana Vishwanathapura Date: Tue, 9 May 2023 05:08:24 +0000 Subject: [PATCH] drm/xe: Handle -EDEADLK case in exec ioctl MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With multiple active VMs, under memory pressure, it is possible that ttm_bo_validate() run into -EDEADLK in ttm_mem_evict_wait_busy() and return -ENOMEM. Until ttm properly handles locking in such scenarios, best thing the driver can do is unwind the lock and retry. Update xe_exec_begin to retry validating BOs with a timeout upon -ENOMEM. Reviewed-by: Thomas Hellström Signed-off-by: Niranjana Vishwanathapura Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_exec.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c index ea869f2452ef..3db1b159586e 100644 --- a/drivers/gpu/drm/xe/xe_exec.c +++ b/drivers/gpu/drm/xe/xe_exec.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "xe_bo.h" #include "xe_device.h" @@ -91,6 +92,8 @@ * Unlock all */ +#define XE_EXEC_BIND_RETRY_TIMEOUT_MS 1000 + static int xe_exec_begin(struct xe_engine *e, struct ww_acquire_ctx *ww, struct ttm_validate_buffer tv_onstack[], struct ttm_validate_buffer **tv, @@ -99,12 +102,14 @@ static int xe_exec_begin(struct xe_engine *e, struct ww_acquire_ctx *ww, struct xe_vm *vm = e->vm; struct xe_vma *vma; LIST_HEAD(dups); - int err; + ktime_t end = 0; + int err = 0; *tv = NULL; if (xe_vm_no_dma_fences(e->vm)) return 0; +retry: err = xe_vm_lock_dma_resv(vm, ww, tv_onstack, tv, objs, true, 1); if (err) return err; @@ -122,11 +127,27 @@ static int xe_exec_begin(struct xe_engine *e, struct ww_acquire_ctx *ww, if (err) { xe_vm_unlock_dma_resv(vm, tv_onstack, *tv, ww, objs); *tv = NULL; - return err; + break; } } - return 0; + /* + * With multiple active VMs, under memory pressure, it is possible that + * ttm_bo_validate() run into -EDEADLK and in such case returns -ENOMEM. + * Until ttm properly handles locking in such scenarios, best thing the + * driver can do is retry with a timeout. + */ + if (err == -ENOMEM) { + ktime_t cur = ktime_get(); + + end = end ? : ktime_add_ms(cur, XE_EXEC_BIND_RETRY_TIMEOUT_MS); + if (ktime_before(cur, end)) { + msleep(20); + goto retry; + } + } + + return err; } static void xe_exec_end(struct xe_engine *e,