mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Chris Wilson](/assets/img/avatar_default.png)
In commit 9144d75e22
("include/linux/bitops.h: introduce BITS_PER_TYPE"),
we made BITS_PER_TYPE available to all and now we can use the macro to
replace some open-coded computation of sizeof(T) * BITS_PER_BYTE.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180926104707.17410-1-chris@chris-wilson.co.uk
412 lines
11 KiB
C
412 lines
11 KiB
C
/*
|
|
* Copyright © 2017 Intel Corporation
|
|
*
|
|
* 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, sublicense,
|
|
* 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 NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS 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 <linux/slab.h>
|
|
|
|
#include "i915_syncmap.h"
|
|
|
|
#include "i915_gem.h" /* GEM_BUG_ON() */
|
|
#include "i915_selftest.h"
|
|
|
|
#define SHIFT ilog2(KSYNCMAP)
|
|
#define MASK (KSYNCMAP - 1)
|
|
|
|
/*
|
|
* struct i915_syncmap is a layer of a radixtree that maps a u64 fence
|
|
* context id to the last u32 fence seqno waited upon from that context.
|
|
* Unlike lib/radixtree it uses a parent pointer that allows traversal back to
|
|
* the root. This allows us to access the whole tree via a single pointer
|
|
* to the most recently used layer. We expect fence contexts to be dense
|
|
* and most reuse to be on the same i915_gem_context but on neighbouring
|
|
* engines (i.e. on adjacent contexts) and reuse the same leaf, a very
|
|
* effective lookup cache. If the new lookup is not on the same leaf, we
|
|
* expect it to be on the neighbouring branch.
|
|
*
|
|
* A leaf holds an array of u32 seqno, and has height 0. The bitmap field
|
|
* allows us to store whether a particular seqno is valid (i.e. allows us
|
|
* to distinguish unset from 0).
|
|
*
|
|
* A branch holds an array of layer pointers, and has height > 0, and always
|
|
* has at least 2 layers (either branches or leaves) below it.
|
|
*
|
|
* For example,
|
|
* for x in
|
|
* 0 1 2 0x10 0x11 0x200 0x201
|
|
* 0x500000 0x500001 0x503000 0x503001
|
|
* 0xE<<60:
|
|
* i915_syncmap_set(&sync, x, lower_32_bits(x));
|
|
* will build a tree like:
|
|
* 0xXXXXXXXXXXXXXXXX
|
|
* 0-> 0x0000000000XXXXXX
|
|
* | 0-> 0x0000000000000XXX
|
|
* | | 0-> 0x00000000000000XX
|
|
* | | | 0-> 0x000000000000000X 0:0, 1:1, 2:2
|
|
* | | | 1-> 0x000000000000001X 0:10, 1:11
|
|
* | | 2-> 0x000000000000020X 0:200, 1:201
|
|
* | 5-> 0x000000000050XXXX
|
|
* | 0-> 0x000000000050000X 0:500000, 1:500001
|
|
* | 3-> 0x000000000050300X 0:503000, 1:503001
|
|
* e-> 0xe00000000000000X e:e
|
|
*/
|
|
|
|
struct i915_syncmap {
|
|
u64 prefix;
|
|
unsigned int height;
|
|
unsigned int bitmap;
|
|
struct i915_syncmap *parent;
|
|
/*
|
|
* Following this header is an array of either seqno or child pointers:
|
|
* union {
|
|
* u32 seqno[KSYNCMAP];
|
|
* struct i915_syncmap *child[KSYNCMAP];
|
|
* };
|
|
*/
|
|
};
|
|
|
|
/**
|
|
* i915_syncmap_init -- initialise the #i915_syncmap
|
|
* @root: pointer to the #i915_syncmap
|
|
*/
|
|
void i915_syncmap_init(struct i915_syncmap **root)
|
|
{
|
|
BUILD_BUG_ON_NOT_POWER_OF_2(KSYNCMAP);
|
|
BUILD_BUG_ON_NOT_POWER_OF_2(SHIFT);
|
|
BUILD_BUG_ON(KSYNCMAP > BITS_PER_TYPE((*root)->bitmap));
|
|
*root = NULL;
|
|
}
|
|
|
|
static inline u32 *__sync_seqno(struct i915_syncmap *p)
|
|
{
|
|
GEM_BUG_ON(p->height);
|
|
return (u32 *)(p + 1);
|
|
}
|
|
|
|
static inline struct i915_syncmap **__sync_child(struct i915_syncmap *p)
|
|
{
|
|
GEM_BUG_ON(!p->height);
|
|
return (struct i915_syncmap **)(p + 1);
|
|
}
|
|
|
|
static inline unsigned int
|
|
__sync_branch_idx(const struct i915_syncmap *p, u64 id)
|
|
{
|
|
return (id >> p->height) & MASK;
|
|
}
|
|
|
|
static inline unsigned int
|
|
__sync_leaf_idx(const struct i915_syncmap *p, u64 id)
|
|
{
|
|
GEM_BUG_ON(p->height);
|
|
return id & MASK;
|
|
}
|
|
|
|
static inline u64 __sync_branch_prefix(const struct i915_syncmap *p, u64 id)
|
|
{
|
|
return id >> p->height >> SHIFT;
|
|
}
|
|
|
|
static inline u64 __sync_leaf_prefix(const struct i915_syncmap *p, u64 id)
|
|
{
|
|
GEM_BUG_ON(p->height);
|
|
return id >> SHIFT;
|
|
}
|
|
|
|
static inline bool seqno_later(u32 a, u32 b)
|
|
{
|
|
return (s32)(a - b) >= 0;
|
|
}
|
|
|
|
/**
|
|
* i915_syncmap_is_later -- compare against the last know sync point
|
|
* @root: pointer to the #i915_syncmap
|
|
* @id: the context id (other timeline) we are synchronising to
|
|
* @seqno: the sequence number along the other timeline
|
|
*
|
|
* If we have already synchronised this @root timeline with another (@id) then
|
|
* we can omit any repeated or earlier synchronisation requests. If the two
|
|
* timelines are already coupled, we can also omit the dependency between the
|
|
* two as that is already known via the timeline.
|
|
*
|
|
* Returns true if the two timelines are already synchronised wrt to @seqno,
|
|
* false if not and the synchronisation must be emitted.
|
|
*/
|
|
bool i915_syncmap_is_later(struct i915_syncmap **root, u64 id, u32 seqno)
|
|
{
|
|
struct i915_syncmap *p;
|
|
unsigned int idx;
|
|
|
|
p = *root;
|
|
if (!p)
|
|
return false;
|
|
|
|
if (likely(__sync_leaf_prefix(p, id) == p->prefix))
|
|
goto found;
|
|
|
|
/* First climb the tree back to a parent branch */
|
|
do {
|
|
p = p->parent;
|
|
if (!p)
|
|
return false;
|
|
|
|
if (__sync_branch_prefix(p, id) == p->prefix)
|
|
break;
|
|
} while (1);
|
|
|
|
/* And then descend again until we find our leaf */
|
|
do {
|
|
if (!p->height)
|
|
break;
|
|
|
|
p = __sync_child(p)[__sync_branch_idx(p, id)];
|
|
if (!p)
|
|
return false;
|
|
|
|
if (__sync_branch_prefix(p, id) != p->prefix)
|
|
return false;
|
|
} while (1);
|
|
|
|
*root = p;
|
|
found:
|
|
idx = __sync_leaf_idx(p, id);
|
|
if (!(p->bitmap & BIT(idx)))
|
|
return false;
|
|
|
|
return seqno_later(__sync_seqno(p)[idx], seqno);
|
|
}
|
|
|
|
static struct i915_syncmap *
|
|
__sync_alloc_leaf(struct i915_syncmap *parent, u64 id)
|
|
{
|
|
struct i915_syncmap *p;
|
|
|
|
p = kmalloc(sizeof(*p) + KSYNCMAP * sizeof(u32), GFP_KERNEL);
|
|
if (unlikely(!p))
|
|
return NULL;
|
|
|
|
p->parent = parent;
|
|
p->height = 0;
|
|
p->bitmap = 0;
|
|
p->prefix = __sync_leaf_prefix(p, id);
|
|
return p;
|
|
}
|
|
|
|
static inline void __sync_set_seqno(struct i915_syncmap *p, u64 id, u32 seqno)
|
|
{
|
|
unsigned int idx = __sync_leaf_idx(p, id);
|
|
|
|
p->bitmap |= BIT(idx);
|
|
__sync_seqno(p)[idx] = seqno;
|
|
}
|
|
|
|
static inline void __sync_set_child(struct i915_syncmap *p,
|
|
unsigned int idx,
|
|
struct i915_syncmap *child)
|
|
{
|
|
p->bitmap |= BIT(idx);
|
|
__sync_child(p)[idx] = child;
|
|
}
|
|
|
|
static noinline int __sync_set(struct i915_syncmap **root, u64 id, u32 seqno)
|
|
{
|
|
struct i915_syncmap *p = *root;
|
|
unsigned int idx;
|
|
|
|
if (!p) {
|
|
p = __sync_alloc_leaf(NULL, id);
|
|
if (unlikely(!p))
|
|
return -ENOMEM;
|
|
|
|
goto found;
|
|
}
|
|
|
|
/* Caller handled the likely cached case */
|
|
GEM_BUG_ON(__sync_leaf_prefix(p, id) == p->prefix);
|
|
|
|
/* Climb back up the tree until we find a common prefix */
|
|
do {
|
|
if (!p->parent)
|
|
break;
|
|
|
|
p = p->parent;
|
|
|
|
if (__sync_branch_prefix(p, id) == p->prefix)
|
|
break;
|
|
} while (1);
|
|
|
|
/*
|
|
* No shortcut, we have to descend the tree to find the right layer
|
|
* containing this fence.
|
|
*
|
|
* Each layer in the tree holds 16 (KSYNCMAP) pointers, either fences
|
|
* or lower layers. Leaf nodes (height = 0) contain the fences, all
|
|
* other nodes (height > 0) are internal layers that point to a lower
|
|
* node. Each internal layer has at least 2 descendents.
|
|
*
|
|
* Starting at the top, we check whether the current prefix matches. If
|
|
* it doesn't, we have gone past our target and need to insert a join
|
|
* into the tree, and a new leaf node for the target as a descendent
|
|
* of the join, as well as the original layer.
|
|
*
|
|
* The matching prefix means we are still following the right branch
|
|
* of the tree. If it has height 0, we have found our leaf and just
|
|
* need to replace the fence slot with ourselves. If the height is
|
|
* not zero, our slot contains the next layer in the tree (unless
|
|
* it is empty, in which case we can add ourselves as a new leaf).
|
|
* As descend the tree the prefix grows (and height decreases).
|
|
*/
|
|
do {
|
|
struct i915_syncmap *next;
|
|
|
|
if (__sync_branch_prefix(p, id) != p->prefix) {
|
|
unsigned int above;
|
|
|
|
/* Insert a join above the current layer */
|
|
next = kzalloc(sizeof(*next) + KSYNCMAP * sizeof(next),
|
|
GFP_KERNEL);
|
|
if (unlikely(!next))
|
|
return -ENOMEM;
|
|
|
|
/* Compute the height at which these two diverge */
|
|
above = fls64(__sync_branch_prefix(p, id) ^ p->prefix);
|
|
above = round_up(above, SHIFT);
|
|
next->height = above + p->height;
|
|
next->prefix = __sync_branch_prefix(next, id);
|
|
|
|
/* Insert the join into the parent */
|
|
if (p->parent) {
|
|
idx = __sync_branch_idx(p->parent, id);
|
|
__sync_child(p->parent)[idx] = next;
|
|
GEM_BUG_ON(!(p->parent->bitmap & BIT(idx)));
|
|
}
|
|
next->parent = p->parent;
|
|
|
|
/* Compute the idx of the other branch, not our id! */
|
|
idx = p->prefix >> (above - SHIFT) & MASK;
|
|
__sync_set_child(next, idx, p);
|
|
p->parent = next;
|
|
|
|
/* Ascend to the join */
|
|
p = next;
|
|
} else {
|
|
if (!p->height)
|
|
break;
|
|
}
|
|
|
|
/* Descend into the next layer */
|
|
GEM_BUG_ON(!p->height);
|
|
idx = __sync_branch_idx(p, id);
|
|
next = __sync_child(p)[idx];
|
|
if (!next) {
|
|
next = __sync_alloc_leaf(p, id);
|
|
if (unlikely(!next))
|
|
return -ENOMEM;
|
|
|
|
__sync_set_child(p, idx, next);
|
|
p = next;
|
|
break;
|
|
}
|
|
|
|
p = next;
|
|
} while (1);
|
|
|
|
found:
|
|
GEM_BUG_ON(p->prefix != __sync_leaf_prefix(p, id));
|
|
__sync_set_seqno(p, id, seqno);
|
|
*root = p;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* i915_syncmap_set -- mark the most recent syncpoint between contexts
|
|
* @root: pointer to the #i915_syncmap
|
|
* @id: the context id (other timeline) we have synchronised to
|
|
* @seqno: the sequence number along the other timeline
|
|
*
|
|
* When we synchronise this @root timeline with another (@id), we also know
|
|
* that we have synchronized with all previous seqno along that timeline. If
|
|
* we then have a request to synchronise with the same seqno or older, we can
|
|
* omit it, see i915_syncmap_is_later()
|
|
*
|
|
* Returns 0 on success, or a negative error code.
|
|
*/
|
|
int i915_syncmap_set(struct i915_syncmap **root, u64 id, u32 seqno)
|
|
{
|
|
struct i915_syncmap *p = *root;
|
|
|
|
/*
|
|
* We expect to be called in sequence following is_later(id), which
|
|
* should have preloaded the root for us.
|
|
*/
|
|
if (likely(p && __sync_leaf_prefix(p, id) == p->prefix)) {
|
|
__sync_set_seqno(p, id, seqno);
|
|
return 0;
|
|
}
|
|
|
|
return __sync_set(root, id, seqno);
|
|
}
|
|
|
|
static void __sync_free(struct i915_syncmap *p)
|
|
{
|
|
if (p->height) {
|
|
unsigned int i;
|
|
|
|
while ((i = ffs(p->bitmap))) {
|
|
p->bitmap &= ~0u << i;
|
|
__sync_free(__sync_child(p)[i - 1]);
|
|
}
|
|
}
|
|
|
|
kfree(p);
|
|
}
|
|
|
|
/**
|
|
* i915_syncmap_free -- free all memory associated with the syncmap
|
|
* @root: pointer to the #i915_syncmap
|
|
*
|
|
* Either when the timeline is to be freed and we no longer need the sync
|
|
* point tracking, or when the fences are all known to be signaled and the
|
|
* sync point tracking is redundant, we can free the #i915_syncmap to recover
|
|
* its allocations.
|
|
*
|
|
* Will reinitialise the @root pointer so that the #i915_syncmap is ready for
|
|
* reuse.
|
|
*/
|
|
void i915_syncmap_free(struct i915_syncmap **root)
|
|
{
|
|
struct i915_syncmap *p;
|
|
|
|
p = *root;
|
|
if (!p)
|
|
return;
|
|
|
|
while (p->parent)
|
|
p = p->parent;
|
|
|
|
__sync_free(p);
|
|
*root = NULL;
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
|
|
#include "selftests/i915_syncmap.c"
|
|
#endif
|