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From 0d738510e75bcf8974def92502d4a557c80d33fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Wed, 22 May 2019 09:51:47 +0200
Subject: [PATCH 2039/2940] drm/ttm: fix busy memory to fail other user v10
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
BOs on the LRU might be blocked during command submission
and cause OOM situations.
Avoid this by blocking for the first busy BO not locked by
the same ticket as the BO we are searching space for.
v10: completely start over with the patch since we didn't
handled a whole bunch of corner cases.
Change-Id: I65309984703ef5acc83ef0bfa7c35ad24150fe9d
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Tested-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Signed-off-by: Chaudhary Amit Kumar <Chaudharyamit.Kumar@amd.com>
---
drivers/gpu/drm/ttm/ttm_bo.c | 77 +++++++++++++++++++++++++++++++-----
1 file changed, 67 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 0afa619c49ab..40b4b1bcd258 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -779,7 +779,7 @@ EXPORT_SYMBOL(ttm_bo_eviction_valuable);
* b. Otherwise, trylock it.
*/
static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
- struct ttm_operation_ctx *ctx, bool *locked)
+ struct ttm_operation_ctx *ctx, bool *locked, bool *busy)
{
bool ret = false;
@@ -789,22 +789,64 @@ static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
if (ctx->flags & TTM_OPT_FLAG_ALLOW_RES_EVICT
|| !list_empty(&bo->ddestroy))
ret = true;
+ *locked = false;
+ if (busy)
+ *busy = false;
} else {
- *locked = reservation_object_trylock(bo->resv);
- ret = *locked;
+ ret = reservation_object_trylock(bo->resv);
+ *locked = ret;
+ if (busy)
+ *busy = !ret;
}
return ret;
}
+/**
+ * ttm_mem_evict_wait_busy - wait for a busy BO to become available
+ *
+ * @busy_bo: BO which couldn't be locked with trylock
+ * @ctx: operation context
+ * @ticket: acquire ticket
+ *
+ * Try to lock a busy buffer object to avoid failing eviction.
+ */
+static int ttm_mem_evict_wait_busy(struct ttm_buffer_object *busy_bo,
+ struct ttm_operation_ctx *ctx,
+ struct ww_acquire_ctx *ticket)
+{
+ int r;
+
+ if (!busy_bo || !ticket)
+ return -EBUSY;
+
+ if (ctx->interruptible)
+ r = reservation_object_lock_interruptible(busy_bo->resv,
+ ticket);
+ else
+ r = reservation_object_lock(busy_bo->resv, ticket);
+
+ /*
+ * TODO: It would be better to keep the BO locked until allocation is at
+ * least tried one more time, but that would mean a much larger rework
+ * of TTM.
+ */
+ if (!r)
+ reservation_object_unlock(busy_bo->resv);
+
+ return r == -EDEADLK ? -EAGAIN : r;
+}
+
+
static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
uint32_t mem_type,
const struct ttm_place *place,
- struct ttm_operation_ctx *ctx)
+ struct ttm_operation_ctx *ctx,
+ struct ww_acquire_ctx *ticket)
{
+ struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
struct ttm_bo_global *glob = bdev->glob;
struct ttm_mem_type_manager *man = &bdev->man[mem_type];
- struct ttm_buffer_object *bo = NULL;
bool locked = false;
unsigned i;
int ret;
@@ -812,8 +854,15 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
spin_lock(&glob->lru_lock);
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
list_for_each_entry(bo, &man->lru[i], lru) {
- if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked))
+ bool busy;
+
+ if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
+ &busy)) {
+ if (busy && !busy_bo &&
+ bo->resv->lock.ctx != ticket)
+ busy_bo = bo;
continue;
+ }
if (place && !bdev->driver->eviction_valuable(bo,
place)) {
@@ -832,8 +881,13 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
}
if (!bo) {
+ if (busy_bo)
+ ttm_bo_get(busy_bo);
spin_unlock(&glob->lru_lock);
- return -EBUSY;
+ ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket);
+ if (busy_bo)
+ ttm_bo_put(busy_bo);
+ return ret;
}
kref_get(&bo->list_kref);
@@ -917,7 +971,8 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
return ret;
if (mem->mm_node)
break;
- ret = ttm_mem_evict_first(bdev, mem->mem_type, place, ctx);
+ ret = ttm_mem_evict_first(bdev, mem->mem_type, place, ctx,
+ bo->resv->lock.ctx);
if (unlikely(ret != 0))
return ret;
} while (1);
@@ -1416,7 +1471,8 @@ static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
while (!list_empty(&man->lru[i])) {
spin_unlock(&glob->lru_lock);
- ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx);
+ ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx,
+ NULL);
if (ret)
return ret;
spin_lock(&glob->lru_lock);
@@ -1771,7 +1827,8 @@ int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx)
spin_lock(&glob->lru_lock);
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
list_for_each_entry(bo, &glob->swap_lru[i], swap) {
- if (ttm_bo_evict_swapout_allowable(bo, ctx, &locked)) {
+ if (ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
+ NULL)) {
ret = 0;
break;
}
--
2.17.1
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