Hi
On Thu, Dec 29, 2016 at 9:48 PM, Daniel Vetter daniel.vetter@ffwll.ch wrote:
Added some boilerplate for the structs, documented members where they are relevant and plenty of markup for hyperlinks all over. And a few small wording polish.
Note that the intro needs some more love after the DRM_MM_INSERT_* patch from Chris has landed.
v2: Spelling fixes (Chris).
v3: Use &struct foo instead of &foo structure (Chris).
Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com
Documentation/gpu/drm-mm.rst | 2 +- drivers/gpu/drm/drm_mm.c | 41 +++++++++++---------- include/drm/drm_mm.h | 84 ++++++++++++++++++++++++++++++++++---------- 3 files changed, 89 insertions(+), 38 deletions(-)
I liked the "DRM Roaster" more than the "Roster"!
Reviewed-by: David Herrmann dh.herrmann@gmail.com
Thanks David
diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index cb5daffcd6be..5355e5ad51a7 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -442,7 +442,7 @@ LRU Scan/Eviction Support
.. kernel-doc:: drivers/gpu/drm/drm_mm.c
- :doc: lru scan roaster
- :doc: lru scan roster
DRM MM Range Allocator Function References
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index e54aa3fa538f..229b3f525dee 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -59,8 +59,8 @@
- The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
- Drivers are free to embed either of them into their own suitable
- datastructures. drm_mm itself will not do any allocations of its own, so if
- drivers choose not to embed nodes they need to still allocate them
- datastructures. drm_mm itself will not do any memory allocations of its own,
- so if drivers choose not to embed nodes they need to still allocate them
- themselves.
- The range allocator also supports reservation of preallocated blocks. This is
@@ -78,7 +78,7 @@
- steep cliff not a real concern. Removing a node again is O(1).
- drm_mm supports a few features: Alignment and range restrictions can be
- supplied. Further more every &drm_mm_node has a color value (which is just an
- supplied. Furthermore every &drm_mm_node has a color value (which is just an
- opaque unsigned long) which in conjunction with a driver callback can be used
- to implement sophisticated placement restrictions. The i915 DRM driver uses
- this to implement guard pages between incompatible caching domains in the
@@ -296,11 +296,11 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
- @mm: drm_mm allocator to insert @node into
- @node: drm_mm_node to insert
- This functions inserts an already set-up drm_mm_node into the allocator,
- meaning that start, size and color must be set by the caller. This is useful
- to initialize the allocator with preallocated objects which must be set-up
- before the range allocator can be set-up, e.g. when taking over a firmware
- framebuffer.
- This functions inserts an already set-up &drm_mm_node into the allocator,
- meaning that start, size and color must be set by the caller. All other
- fields must be cleared to 0. This is useful to initialize the allocator with
- preallocated objects which must be set-up before the range allocator can be
- set-up, e.g. when taking over a firmware framebuffer.
- Returns:
- 0 on success, -ENOSPC if there's no hole where @node is.
@@ -375,7 +375,7 @@ EXPORT_SYMBOL(drm_mm_reserve_node);
- @sflags: flags to fine-tune the allocation search
- @aflags: flags to fine-tune the allocation behavior
- The preallocated node must be cleared to 0.
- The preallocated @node must be cleared to 0.
- Returns:
- 0 on success, -ENOSPC if there's no suitable hole.
@@ -537,7 +537,7 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) EXPORT_SYMBOL(drm_mm_replace_node);
/**
- DOC: lru scan roaster
- DOC: lru scan roster
- Very often GPUs need to have continuous allocations for a given object. When
- evicting objects to make space for a new one it is therefore not most
@@ -549,9 +549,11 @@ EXPORT_SYMBOL(drm_mm_replace_node);
- The DRM range allocator supports this use-case through the scanning
- interfaces. First a scan operation needs to be initialized with
- drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
- objects to the roster (probably by walking an LRU list, but this can be
- freely implemented) (using drm_mm_scan_add_block()) until a suitable hole
- is found or there are no further evictable objects.
- objects to the roster, probably by walking an LRU list, but this can be
- freely implemented. Eviction candiates are added using
- drm_mm_scan_add_block() until a suitable hole is found or there are no
- further evictable objects. Eviction roster metadata is tracked in struct
- &drm_mm_scan.
- The driver must walk through all objects again in exactly the reverse
- order to restore the allocator state. Note that while the allocator is used
@@ -559,7 +561,7 @@ EXPORT_SYMBOL(drm_mm_replace_node);
- Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
- reported true) in the scan, and any overlapping nodes after color adjustment
- (drm_mm_scan_evict_color()). Adding and removing an object is O(1), and
- (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
- since freeing a node is also O(1) the overall complexity is
- O(scanned_objects). So like the free stack which needs to be walked before a
- scan operation even begins this is linear in the number of objects. It
@@ -705,14 +707,15 @@ EXPORT_SYMBOL(drm_mm_scan_add_block);
- @scan: the active drm_mm scanner
- @node: drm_mm_node to remove
- Nodes _must_ be removed in exactly the reverse order from the scan list as
- they have been added (e.g. using list_add as they are added and then
- list_for_each over that eviction list to remove), otherwise the internal
- Nodes **must** be removed in exactly the reverse order from the scan list as
- they have been added (e.g. using list_add() as they are added and then
- list_for_each() over that eviction list to remove), otherwise the internal
- state of the memory manager will be corrupted.
- When the scan list is empty, the selected memory nodes can be freed. An
- immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
- return the just freed block (because its at the top of the free_stack list).
- immediately following drm_mm_insert_node_in_range_generic() or one of the
- simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
- the just freed block (because its at the top of the free_stack list).
- Returns:
- True if this block should be evicted, false otherwise. Will always
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h index 1383ac2328b8..3bddca8fd2b5 100644 --- a/include/drm/drm_mm.h +++ b/include/drm/drm_mm.h @@ -67,16 +67,29 @@ enum drm_mm_allocator_flags { #define DRM_MM_BOTTOMUP DRM_MM_SEARCH_DEFAULT, DRM_MM_CREATE_DEFAULT #define DRM_MM_TOPDOWN DRM_MM_SEARCH_BELOW, DRM_MM_CREATE_TOP
+/**
- struct drm_mm_node - allocated block in the DRM allocator
- This represents an allocated block in a &drm_mm allocator. Except for
- pre-reserved nodes inserted using drm_mm_reserve_node() the structure is
- entirely opaque and should only be accessed through the provided funcions.
- Since allocation of these nodes is entirely handled by the driver they can be
- embedded.
- */
struct drm_mm_node {
/** @color: Opaque driver-private tag. */unsigned long color;/** @start: Start address of the allocated block. */u64 start;/** @size: Size of the allocated block. */u64 size;/* private: */ struct list_head node_list; struct list_head hole_stack; struct rb_node rb; unsigned hole_follows : 1; unsigned allocated : 1; bool scanned_block : 1;
unsigned long color;u64 start;u64 size; u64 __subtree_last; struct drm_mm *mm;#ifdef CONFIG_DRM_DEBUG_MM @@ -84,7 +97,29 @@ struct drm_mm_node { #endif };
+/**
- struct drm_mm - DRM allocator
- DRM range allocator with a few special functions and features geared towards
- managing GPU memory. Except for the @color_adjust callback the structure is
- entirely opaque and should only be accessed through the provided functions
- and macros. This structure can be embedded into larger driver structures.
- */
struct drm_mm {
/*** @color_adjust:** Optional driver callback to further apply restrictions on a hole. The* node argument points at the node containing the hole from which the* block would be allocated (see drm_mm_hole_follows() and friends). The* other arguments are the size of the block to be allocated. The driver* can adjust the start and end as needed to e.g. insert guard pages.*/void (*color_adjust)(const struct drm_mm_node *node,unsigned long color,u64 *start, u64 *end);/* private: */ /* List of all memory nodes that immediately precede a free hole. */ struct list_head hole_stack; /* head_node.node_list is the list of all memory nodes, ordered@@ -93,14 +128,20 @@ struct drm_mm { /* Keep an interval_tree for fast lookup of drm_mm_nodes by address. */ struct rb_root interval_tree;
void (*color_adjust)(const struct drm_mm_node *node,unsigned long color,u64 *start, u64 *end);unsigned long scan_active;};
+/**
- struct drm_mm_scan - DRM allocator eviction roaster data
- This structure tracks data needed for the eviction roaster set up using
- drm_mm_scan_init(), and used with drm_mm_scan_add_block() and
- drm_mm_scan_remove_block(). The structure is entirely opaque and should only
- be accessed through the provided functions and macros. It is meant to be
- allocated temporarily by the driver on the stack.
- */
struct drm_mm_scan {
/* private: */ struct drm_mm *mm; u64 size;@@ -159,7 +200,8 @@ static inline bool drm_mm_initialized(const struct drm_mm *mm)
- Holes are embedded into the drm_mm using the tail of a drm_mm_node.
- If you wish to know whether a hole follows this particular node,
- query this function.
- query this function. See also drm_mm_hole_node_start() and
- drm_mm_hole_node_end().
- Returns:
- True if a hole follows the @node.
@@ -228,23 +270,23 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
/**
- drm_mm_for_each_node - iterator to walk over all allocated nodes
- @entry: drm_mm_node structure to assign to in each iteration step
- @mm: drm_mm allocator to walk
- @entry: &struct drm_mm_node to assign to in each iteration step
- @mm: &drm_mm allocator to walk
- This iterator walks over all nodes in the range allocator. It is implemented
- with list_for_each, so not save against removal of elements.
*/
- with list_for_each(), so not save against removal of elements.
#define drm_mm_for_each_node(entry, mm) \ list_for_each_entry(entry, drm_mm_nodes(mm), node_list)
/**
- drm_mm_for_each_node_safe - iterator to walk over all allocated nodes
- @entry: drm_mm_node structure to assign to in each iteration step
- @next: drm_mm_node structure to store the next step
- @mm: drm_mm allocator to walk
- @entry: &struct drm_mm_node to assign to in each iteration step
- @next: &struct drm_mm_node to store the next step
- @mm: &drm_mm allocator to walk
- This iterator walks over all nodes in the range allocator. It is implemented
- with list_for_each_safe, so save against removal of elements.
*/
- with list_for_each_safe(), so save against removal of elements.
#define drm_mm_for_each_node_safe(entry, next, mm) \ list_for_each_entry_safe(entry, next, drm_mm_nodes(mm), node_list) @@ -259,13 +301,13 @@ static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
/**
- drm_mm_for_each_hole - iterator to walk over all holes
- @entry: drm_mm_node used internally to track progress
- @mm: drm_mm allocator to walk
- @entry: &drm_mm_node used internally to track progress
- @mm: &drm_mm allocator to walk
- @hole_start: ulong variable to assign the hole start to on each iteration
- @hole_end: ulong variable to assign the hole end to on each iteration
- This iterator walks over all holes in the range allocator. It is implemented
- with list_for_each, so not save against removal of elements. @entry is used
- with list_for_each(), so not save against removal of elements. @entry is used
- internally and will not reflect a real drm_mm_node for the very first hole.
- Hence users of this iterator may not access it.
@@ -334,6 +376,9 @@ static inline int drm_mm_insert_node_in_range(struct drm_mm *mm,
- @sflags: flags to fine-tune the allocation search
- @aflags: flags to fine-tune the allocation behavior
- This is a simplified version of drm_mm_insert_node_in_range_generic() with no
- range restrictions applied.
- The preallocated node must be cleared to 0.
- Returns:
@@ -434,6 +479,9 @@ void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
- @color: opaque tag value to use for the allocation
- @flags: flags to specify how the allocation will be performed afterwards
- This is a simplified version of drm_mm_scan_init_with_range() with no range
- restrictions applied.
- This simply sets up the scanning routines with the parameters for the desired
- hole.
-- 2.7.4
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