cgroup resource allocation has to be handled in TTM, so -EAGAIN from
cgroups can be converted into -ENOSPC, and the limitcg can be properly
evicted in ttm code.

When hitting a resource limit through -EAGAIN, the cgroup for which the
limit is hit is also returned. This allows eviction to delete only from
cgroups which are a subgroup of the current cgroup.

The returned CSS is used to determine if eviction is valuable for a
given resource, and allows TTM to only target specific resources to
lower memory usage.

Co-developed-by: Friedrich Vock <friedrich.v...@gmx.de>
Signed-off-by: Friedrich Vock <friedrich.v...@gmx.de>
Co-developed-by: Maxime Ripard <mrip...@kernel.org>
Signed-off-by: Maxime Ripard <mrip...@kernel.org>
Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
---
 drivers/gpu/drm/ttm/tests/ttm_bo_test.c       | 18 +++---
 .../gpu/drm/ttm/tests/ttm_bo_validate_test.c  |  4 +-
 drivers/gpu/drm/ttm/tests/ttm_resource_test.c |  2 +-
 drivers/gpu/drm/ttm/ttm_bo.c                  | 57 ++++++++++++++++---
 drivers/gpu/drm/ttm/ttm_resource.c            | 24 +++++++-
 include/drm/ttm/ttm_resource.h                | 16 +++++-
 6 files changed, 98 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c 
b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
index 3139fd9128d84..f8f20d2f61740 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
@@ -258,13 +258,13 @@ static void ttm_bo_unreserve_basic(struct kunit *test)
        bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
        bo->priority = bo_prio;
 
-       err = ttm_resource_alloc(bo, place, &res1);
+       err = ttm_resource_alloc(bo, place, &res1, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
 
        bo->resource = res1;
 
        /* Add a dummy resource to populate LRU */
-       ttm_resource_alloc(bo, place, &res2);
+       ttm_resource_alloc(bo, place, &res2, NULL);
 
        dma_resv_lock(bo->base.resv, NULL);
        ttm_bo_unreserve(bo);
@@ -300,12 +300,12 @@ static void ttm_bo_unreserve_pinned(struct kunit *test)
        dma_resv_lock(bo->base.resv, NULL);
        ttm_bo_pin(bo);
 
-       err = ttm_resource_alloc(bo, place, &res1);
+       err = ttm_resource_alloc(bo, place, &res1, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo->resource = res1;
 
        /* Add a dummy resource to the pinned list */
-       err = ttm_resource_alloc(bo, place, &res2);
+       err = ttm_resource_alloc(bo, place, &res2, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        KUNIT_ASSERT_EQ(test,
                        list_is_last(&res2->lru.link, 
&priv->ttm_dev->unevictable), 1);
@@ -355,7 +355,7 @@ static void ttm_bo_unreserve_bulk(struct kunit *test)
        ttm_bo_set_bulk_move(bo1, &lru_bulk_move);
        dma_resv_unlock(bo1->base.resv);
 
-       err = ttm_resource_alloc(bo1, place, &res1);
+       err = ttm_resource_alloc(bo1, place, &res1, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo1->resource = res1;
 
@@ -363,7 +363,7 @@ static void ttm_bo_unreserve_bulk(struct kunit *test)
        ttm_bo_set_bulk_move(bo2, &lru_bulk_move);
        dma_resv_unlock(bo2->base.resv);
 
-       err = ttm_resource_alloc(bo2, place, &res2);
+       err = ttm_resource_alloc(bo2, place, &res2, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo2->resource = res2;
 
@@ -401,7 +401,7 @@ static void ttm_bo_put_basic(struct kunit *test)
        bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
        bo->type = ttm_bo_type_device;
 
-       err = ttm_resource_alloc(bo, place, &res);
+       err = ttm_resource_alloc(bo, place, &res, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo->resource = res;
 
@@ -518,7 +518,7 @@ static void ttm_bo_pin_unpin_resource(struct kunit *test)
 
        bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
 
-       err = ttm_resource_alloc(bo, place, &res);
+       err = ttm_resource_alloc(bo, place, &res, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo->resource = res;
 
@@ -569,7 +569,7 @@ static void ttm_bo_multiple_pin_one_unpin(struct kunit 
*test)
 
        bo = ttm_bo_kunit_init(test, test->priv, BO_SIZE, NULL);
 
-       err = ttm_resource_alloc(bo, place, &res);
+       err = ttm_resource_alloc(bo, place, &res, NULL);
        KUNIT_ASSERT_EQ(test, err, 0);
        bo->resource = res;
 
diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c 
b/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
index 1adf18481ea05..3148f5d3dbd66 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_bo_validate_test.c
@@ -542,7 +542,7 @@ static void ttm_bo_validate_no_placement_signaled(struct 
kunit *test)
                bo->ttm = old_tt;
        }
 
-       err = ttm_resource_alloc(bo, place, &bo->resource);
+       err = ttm_resource_alloc(bo, place, &bo->resource, NULL);
        KUNIT_EXPECT_EQ(test, err, 0);
        KUNIT_ASSERT_EQ(test, man->usage, size);
 
@@ -603,7 +603,7 @@ static void 
ttm_bo_validate_no_placement_not_signaled(struct kunit *test)
        bo = ttm_bo_kunit_init(test, test->priv, size, NULL);
        bo->type = params->bo_type;
 
-       err = ttm_resource_alloc(bo, place, &bo->resource);
+       err = ttm_resource_alloc(bo, place, &bo->resource, NULL);
        KUNIT_EXPECT_EQ(test, err, 0);
 
        placement = kunit_kzalloc(test, sizeof(*placement), GFP_KERNEL);
diff --git a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c 
b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
index a9f4b81921c3c..e6ea2bd01f07a 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_resource_test.c
@@ -302,7 +302,7 @@ static void ttm_sys_man_free_basic(struct kunit *test)
        res = kunit_kzalloc(test, sizeof(*res), GFP_KERNEL);
        KUNIT_ASSERT_NOT_NULL(test, res);
 
-       ttm_resource_alloc(bo, place, &res);
+       ttm_resource_alloc(bo, place, &res, NULL);
 
        man = ttm_manager_type(priv->devs->ttm_dev, mem_type);
        man->func->free(man, res);
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 48c5365efca1c..5bdebfdc95e92 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -42,6 +42,7 @@
 #include <linux/file.h>
 #include <linux/module.h>
 #include <linux/atomic.h>
+#include <linux/cgroup_dev.h>
 #include <linux/dma-resv.h>
 
 #include "ttm_module.h"
@@ -447,7 +448,7 @@ int ttm_bo_evict_first(struct ttm_device *bdev, struct 
ttm_resource_manager *man
        struct ttm_buffer_object *bo;
        struct ttm_resource *res;
        unsigned int mem_type;
-       int ret = 0;
+       int ret;
 
        spin_lock(&bdev->lru_lock);
        res = ttm_resource_manager_first(man, &cursor);
@@ -499,14 +500,28 @@ struct ttm_bo_evict_walk {
        struct ttm_resource **res;
        /** @evicted: Number of successful evictions. */
        unsigned long evicted;
+
+       /** @limit_pool: Which pool limit we should test against */
+       struct dev_cgroup_pool_state *limit_pool;
+       /** @try_low: Whether we should attempt to evict BO's with low 
watermark threshold */
+       bool try_low;
+       /** @hit_low: If we cannot evict a bo when @try_low is false (first 
pass) */
+       bool hit_low;
 };
 
 static s64 ttm_bo_evict_cb(struct ttm_lru_walk *walk, struct ttm_buffer_object 
*bo)
 {
        struct ttm_bo_evict_walk *evict_walk =
                container_of(walk, typeof(*evict_walk), walk);
+       struct ttm_resource_manager *man =
+                       ttm_manager_type(bo->bdev, bo->resource->mem_type);
        s64 lret;
 
+       if (!dev_cgroup_state_evict_valuable(man->cgdev, man->cgidx,
+                                            evict_walk->limit_pool, 
bo->resource->css,
+                                            evict_walk->try_low, 
&evict_walk->hit_low))
+               return 0;
+
        if (bo->pin_count || !bo->bdev->funcs->eviction_valuable(bo, 
evict_walk->place))
                return 0;
 
@@ -524,7 +539,7 @@ static s64 ttm_bo_evict_cb(struct ttm_lru_walk *walk, 
struct ttm_buffer_object *
        evict_walk->evicted++;
        if (evict_walk->res)
                lret = ttm_resource_alloc(evict_walk->evictor, 
evict_walk->place,
-                                         evict_walk->res);
+                                         evict_walk->res, NULL);
        if (lret == 0)
                return 1;
 out:
@@ -545,7 +560,8 @@ static int ttm_bo_evict_alloc(struct ttm_device *bdev,
                              struct ttm_buffer_object *evictor,
                              struct ttm_operation_ctx *ctx,
                              struct ww_acquire_ctx *ticket,
-                             struct ttm_resource **res)
+                             struct ttm_resource **res,
+                             struct dev_cgroup_pool_state *limit_pool)
 {
        struct ttm_bo_evict_walk evict_walk = {
                .walk = {
@@ -556,22 +572,39 @@ static int ttm_bo_evict_alloc(struct ttm_device *bdev,
                .place = place,
                .evictor = evictor,
                .res = res,
+               .limit_pool = limit_pool,
        };
        s64 lret;
 
        evict_walk.walk.trylock_only = true;
        lret = ttm_lru_walk_for_evict(&evict_walk.walk, bdev, man, 1);
+
+       /* One more attempt if we hit low limit? */
+       if (!lret && evict_walk.hit_low) {
+               evict_walk.try_low = true;
+               lret = ttm_lru_walk_for_evict(&evict_walk.walk, bdev, man, 1);
+       }
        if (lret || !ticket)
                goto out;
 
+       /* Reset low limit */
+       evict_walk.try_low = evict_walk.hit_low = false;
        /* If ticket-locking, repeat while making progress. */
        evict_walk.walk.trylock_only = false;
+
+retry:
        do {
                /* The walk may clear the evict_walk.walk.ticket field */
                evict_walk.walk.ticket = ticket;
                evict_walk.evicted = 0;
                lret = ttm_lru_walk_for_evict(&evict_walk.walk, bdev, man, 1);
        } while (!lret && evict_walk.evicted);
+
+       /* We hit the low limit? Try once more */
+       if (!lret && evict_walk.hit_low && !evict_walk.try_low) {
+               evict_walk.try_low = true;
+               goto retry;
+       }
 out:
        if (lret < 0)
                return lret;
@@ -689,6 +722,7 @@ static int ttm_bo_alloc_resource(struct ttm_buffer_object 
*bo,
 
        for (i = 0; i < placement->num_placement; ++i) {
                const struct ttm_place *place = &placement->placement[i];
+               struct dev_cgroup_pool_state *limit_pool = NULL;
                struct ttm_resource_manager *man;
                bool may_evict;
 
@@ -701,15 +735,20 @@ static int ttm_bo_alloc_resource(struct ttm_buffer_object 
*bo,
                        continue;
 
                may_evict = (force_space && place->mem_type != TTM_PL_SYSTEM);
-               ret = ttm_resource_alloc(bo, place, res);
+               ret = ttm_resource_alloc(bo, place, res, force_space ? 
&limit_pool : NULL);
                if (ret) {
-                       if (ret != -ENOSPC)
+                       if (ret != -ENOSPC && ret != -EAGAIN) {
+                               dev_cgroup_pool_state_put(limit_pool);
                                return ret;
-                       if (!may_evict)
+                       }
+                       if (!may_evict) {
+                               dev_cgroup_pool_state_put(limit_pool);
                                continue;
+                       }
 
                        ret = ttm_bo_evict_alloc(bdev, man, place, bo, ctx,
-                                                ticket, res);
+                                                ticket, res, limit_pool);
+                       dev_cgroup_pool_state_put(limit_pool);
                        if (ret == -EBUSY)
                                continue;
                        if (ret)
@@ -1056,6 +1095,8 @@ struct ttm_bo_swapout_walk {
        struct ttm_lru_walk walk;
        /** @gfp_flags: The gfp flags to use for ttm_tt_swapout() */
        gfp_t gfp_flags;
+
+       bool hit_low, evict_low;
 };
 
 static s64
@@ -1106,7 +1147,7 @@ ttm_bo_swapout_cb(struct ttm_lru_walk *walk, struct 
ttm_buffer_object *bo)
 
                memset(&hop, 0, sizeof(hop));
                place.mem_type = TTM_PL_SYSTEM;
-               ret = ttm_resource_alloc(bo, &place, &evict_mem);
+               ret = ttm_resource_alloc(bo, &place, &evict_mem, NULL);
                if (ret)
                        goto out;
 
diff --git a/drivers/gpu/drm/ttm/ttm_resource.c 
b/drivers/gpu/drm/ttm/ttm_resource.c
index a87665eb28a62..93190f7330b5c 100644
--- a/drivers/gpu/drm/ttm/ttm_resource.c
+++ b/drivers/gpu/drm/ttm/ttm_resource.c
@@ -26,6 +26,7 @@
 #include <linux/io-mapping.h>
 #include <linux/iosys-map.h>
 #include <linux/scatterlist.h>
+#include <linux/cgroup_dev.h>
 
 #include <drm/ttm/ttm_bo.h>
 #include <drm/ttm/ttm_placement.h>
@@ -350,15 +351,29 @@ EXPORT_SYMBOL(ttm_resource_fini);
 
 int ttm_resource_alloc(struct ttm_buffer_object *bo,
                       const struct ttm_place *place,
-                      struct ttm_resource **res_ptr)
+                      struct ttm_resource **res_ptr,
+                      struct dev_cgroup_pool_state **ret_limit_pool)
 {
        struct ttm_resource_manager *man =
                ttm_manager_type(bo->bdev, place->mem_type);
+       struct dev_cgroup_pool_state *pool = NULL;
        int ret;
 
+       if (man->cgdev) {
+               ret = dev_cgroup_try_charge(man->cgdev, man->cgidx,
+                                           bo->base.size, &pool, 
ret_limit_pool);
+               if (ret)
+                       return ret;
+       }
+
        ret = man->func->alloc(man, bo, place, res_ptr);
-       if (ret)
+       if (ret) {
+               if (pool)
+                       dev_cgroup_uncharge(pool, man->cgidx, bo->base.size);
                return ret;
+       }
+
+       (*res_ptr)->css = pool;
 
        spin_lock(&bo->bdev->lru_lock);
        ttm_resource_add_bulk_move(*res_ptr, bo);
@@ -370,6 +385,7 @@ EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_resource_alloc);
 void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res)
 {
        struct ttm_resource_manager *man;
+       struct dev_cgroup_pool_state *pool;
 
        if (!*res)
                return;
@@ -377,9 +393,13 @@ void ttm_resource_free(struct ttm_buffer_object *bo, 
struct ttm_resource **res)
        spin_lock(&bo->bdev->lru_lock);
        ttm_resource_del_bulk_move(*res, bo);
        spin_unlock(&bo->bdev->lru_lock);
+
+       pool = (*res)->css;
        man = ttm_manager_type(bo->bdev, (*res)->mem_type);
        man->func->free(man, *res);
        *res = NULL;
+       if (man->cgdev)
+               dev_cgroup_uncharge(pool, man->cgidx, bo->base.size);
 }
 EXPORT_SYMBOL(ttm_resource_free);
 
diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
index be034be56ba1b..12ff4b66c6f7d 100644
--- a/include/drm/ttm/ttm_resource.h
+++ b/include/drm/ttm/ttm_resource.h
@@ -38,6 +38,7 @@
 #define TTM_MAX_BO_PRIORITY    4U
 #define TTM_NUM_MEM_TYPES 8
 
+struct dev_cgroup_device;
 struct ttm_device;
 struct ttm_resource_manager;
 struct ttm_resource;
@@ -211,6 +212,15 @@ struct ttm_resource_manager {
         * bdev->lru_lock.
         */
        uint64_t usage;
+
+       /**
+        * @cgdev: dev_cgroup_device used for memory accounting, if not NULL.
+        */
+       struct dev_cgroup_device *cgdev;
+       /**
+        * @cgidx: Resource index used by this resource manager for cgroup 
accounting
+        */
+       u32 cgidx;
 };
 
 /**
@@ -239,6 +249,7 @@ struct ttm_bus_placement {
  * @placement: Placement flags.
  * @bus: Placement on io bus accessible to the CPU
  * @bo: weak reference to the BO, protected by ttm_device::lru_lock
+ * @css: cgroup state this resource is charged to
  *
  * Structure indicating the placement and space resources used by a
  * buffer object.
@@ -251,6 +262,8 @@ struct ttm_resource {
        struct ttm_bus_placement bus;
        struct ttm_buffer_object *bo;
 
+       struct dev_cgroup_pool_state *css;
+
        /**
         * @lru: Least recently used list, see &ttm_resource_manager.lru
         */
@@ -432,7 +445,8 @@ void ttm_resource_fini(struct ttm_resource_manager *man,
 
 int ttm_resource_alloc(struct ttm_buffer_object *bo,
                       const struct ttm_place *place,
-                      struct ttm_resource **res);
+                      struct ttm_resource **res,
+                      struct dev_cgroup_pool_state **ret_limit_pool);
 void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource 
**res);
 bool ttm_resource_intersects(struct ttm_device *bdev,
                             struct ttm_resource *res,
-- 
2.45.2

Reply via email to