drm: Add the TTM GPU memory manager subsystem.

TTM is a GPU memory manager subsystem designed for use with GPU
devices with various memory types (On-card VRAM, AGP,
PCI apertures etc.). It's essentially a helper library that assists
the DRM driver in creating and managing persistent buffer objects.

TTM manages placement of data and CPU map setup and teardown on
data movement. It can also optionally manage synchronization of
data on a per-buffer-object level.

TTM takes care to provide an always valid virtual user-space address
to a buffer object which makes user-space sub-allocation of
big buffer objects feasible.

TTM uses a fine-grained per buffer-object locking scheme, taking
care to release all relevant locks when waiting for the GPU.
Although this implies some locking overhead, it's probably a big
win for devices with multiple command submission mechanisms, since
the lock contention will be minimal.

TTM can be used with whatever user-space interface the driver
chooses, including GEM. It's used by the upcoming Radeon KMS DRM driver
and is also the GPU memory management core of various new experimental
DRM drivers.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 234 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_memory.c b/drivers/gpu/drm/ttm/ttm_memory.c
new file mode 100644
index 00000000000..87323d4ff68
--- /dev/null
+++ b/drivers/gpu/drm/ttm/ttm_memory.c
@@ -0,0 +1,234 @@
+/**************************************************************************
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "ttm/ttm_memory.h"
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#define TTM_PFX "[TTM] "
+#define TTM_MEMORY_ALLOC_RETRIES 4
+
+/**
+ * At this point we only support a single shrink callback.
+ * Extend this if needed, perhaps using a linked list of callbacks.
+ * Note that this function is reentrant:
+ * many threads may try to swap out at any given time.
+ */
+
+static void ttm_shrink(struct ttm_mem_global *glob, bool from_workqueue,
+                       uint64_t extra)
+{
+        int ret;
+        struct ttm_mem_shrink *shrink;
+        uint64_t target;
+        uint64_t total_target;
+
+        spin_lock(&glob->lock);
+        if (glob->shrink == NULL)
+                goto out;
+
+        if (from_workqueue) {
+                target = glob->swap_limit;
+                total_target = glob->total_memory_swap_limit;
+        } else if (capable(CAP_SYS_ADMIN)) {
+                total_target = glob->emer_total_memory;
+                target = glob->emer_memory;
+        } else {
+                total_target = glob->max_total_memory;
+                target = glob->max_memory;
+        }
+
+        total_target = (extra >= total_target) ? 0 : total_target - extra;
+        target = (extra >= target) ? 0 : target - extra;
+
+        while (glob->used_memory > target ||
+               glob->used_total_memory > total_target) {
+                shrink = glob->shrink;
+                spin_unlock(&glob->lock);
+                ret = shrink->do_shrink(shrink);
+                spin_lock(&glob->lock);
+                if (unlikely(ret != 0))
+                        goto out;
+        }
+out:
+        spin_unlock(&glob->lock);
+}
+
+static void ttm_shrink_work(struct work_struct *work)
+{
+        struct ttm_mem_global *glob =
+            container_of(work, struct ttm_mem_global, work);
+
+        ttm_shrink(glob, true, 0ULL);
+}
+
+int ttm_mem_global_init(struct ttm_mem_global *glob)
+{
+        struct sysinfo si;
+        uint64_t mem;
+
+        spin_lock_init(&glob->lock);
+        glob->swap_queue = create_singlethread_workqueue("ttm_swap");
+        INIT_WORK(&glob->work, ttm_shrink_work);
+        init_waitqueue_head(&glob->queue);
+
+        si_meminfo(&si);
+
+        mem = si.totalram - si.totalhigh;
+        mem *= si.mem_unit;
+
+        glob->max_memory = mem >> 1;
+        glob->emer_memory = (mem >> 1) + (mem >> 2);
+        glob->swap_limit = glob->max_memory - (mem >> 3);
+        glob->used_memory = 0;
+        glob->used_total_memory = 0;
+        glob->shrink = NULL;
+
+        mem = si.totalram;
+        mem *= si.mem_unit;
+
+        glob->max_total_memory = mem >> 1;
+        glob->emer_total_memory = (mem >> 1) + (mem >> 2);
+
+        glob->total_memory_swap_limit = glob->max_total_memory - (mem >> 3);
+
+        printk(KERN_INFO TTM_PFX "TTM available graphics memory: %llu MiB\n",
+               glob->max_total_memory >> 20);
+        printk(KERN_INFO TTM_PFX "TTM available object memory: %llu MiB\n",
+               glob->max_memory >> 20);
+
+        return 0;
+}
+EXPORT_SYMBOL(ttm_mem_global_init);
+
+void ttm_mem_global_release(struct ttm_mem_global *glob)
+{
+        printk(KERN_INFO TTM_PFX "Used total memory is %llu bytes.\n",
+               (unsigned long long)glob->used_total_memory);
+        flush_workqueue(glob->swap_queue);
+        destroy_workqueue(glob->swap_queue);
+        glob->swap_queue = NULL;
+}
+EXPORT_SYMBOL(ttm_mem_global_release);
+
+static inline void ttm_check_swapping(struct ttm_mem_global *glob)
+{
+        bool needs_swapping;
+
+        spin_lock(&glob->lock);
+        needs_swapping = (glob->used_memory > glob->swap_limit ||
+                          glob->used_total_memory >
+                          glob->total_memory_swap_limit);
+        spin_unlock(&glob->lock);
+
+        if (unlikely(needs_swapping))
+                (void)queue_work(glob->swap_queue, &glob->work);
+
+}
+
+void ttm_mem_global_free(struct ttm_mem_global *glob,
+                         uint64_t amount, bool himem)
+{
+        spin_lock(&glob->lock);
+        glob->used_total_memory -= amount;
+        if (!himem)
+                glob->used_memory -= amount;
+        wake_up_all(&glob->queue);
+        spin_unlock(&glob->lock);
+}
+
+static int ttm_mem_global_reserve(struct ttm_mem_global *glob,
+                                  uint64_t amount, bool himem, bool reserve)
+{
+        uint64_t limit;
+        uint64_t lomem_limit;
+        int ret = -ENOMEM;
+
+        spin_lock(&glob->lock);
+
+        if (capable(CAP_SYS_ADMIN)) {
+                limit = glob->emer_total_memory;
+                lomem_limit = glob->emer_memory;
+        } else {
+                limit = glob->max_total_memory;
+                lomem_limit = glob->max_memory;
+        }
+
+        if (unlikely(glob->used_total_memory + amount > limit))
+                goto out_unlock;
+        if (unlikely(!himem && glob->used_memory + amount > lomem_limit))
+                goto out_unlock;
+
+        if (reserve) {
+                glob->used_total_memory += amount;
+                if (!himem)
+                        glob->used_memory += amount;
+        }
+        ret = 0;
+out_unlock:
+        spin_unlock(&glob->lock);
+        ttm_check_swapping(glob);
+
+        return ret;
+}
+
+int ttm_mem_global_alloc(struct ttm_mem_global *glob, uint64_t memory,
+                         bool no_wait, bool interruptible, bool himem)
+{
+        int count = TTM_MEMORY_ALLOC_RETRIES;
+
+        while (unlikely(ttm_mem_global_reserve(glob, memory, himem, true)
+                        != 0)) {
+                if (no_wait)
+                        return -ENOMEM;
+                if (unlikely(count-- == 0))
+                        return -ENOMEM;
+                ttm_shrink(glob, false, memory + (memory >> 2) + 16);
+        }
+
+        return 0;
+}
+
+size_t ttm_round_pot(size_t size)
+{
+        if ((size & (size - 1)) == 0)
+                return size;
+        else if (size > PAGE_SIZE)
+                return PAGE_ALIGN(size);
+        else {
+                size_t tmp_size = 4;
+
+                while (tmp_size < size)
+                        tmp_size <<= 1;
+
+                return tmp_size;
+        }
+        return 0;
+}