freedreno: hold batch references when flushing

[mesa.git] / src / gallium / drivers / freedreno / freedreno_batch_cache.c

/*
 * Copyright (C) 2016 Rob Clark <robclark@freedesktop.org>
 *
 * 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.
 *
 * Authors:
 *    Rob Clark <robclark@freedesktop.org>
 */

#include "util/hash_table.h"
#include "util/set.h"
#include "util/list.h"
#include "util/u_string.h"

#include "freedreno_batch.h"
#include "freedreno_batch_cache.h"
#include "freedreno_context.h"
#include "freedreno_resource.h"

/* Overview:
 *
 *   The batch cache provides lookup for mapping pipe_framebuffer_state
 *   to a batch.
 *
 *   It does this via hashtable, with key that roughly matches the
 *   pipe_framebuffer_state, as described below.
 *
 * Batch Cache hashtable key:
 *
 *   To serialize the key, and to avoid dealing with holding a reference to
 *   pipe_surface's (which hold a reference to pipe_resource and complicate
 *   the whole refcnting thing), the key is variable length and inline's the
 *   pertinent details of the pipe_surface.
 *
 * Batch:
 *
 *   Each batch needs to hold a reference to each resource it depends on (ie.
 *   anything that needs a mem2gmem).  And a weak reference to resources it
 *   renders to.  (If both src[n] and dst[n] are not NULL then they are the
 *   same.)
 *
 *   When a resource is destroyed, we need to remove entries in the batch
 *   cache that reference the resource, to avoid dangling pointer issues.
 *   So each resource holds a hashset of batches which have reference them
 *   in their hashtable key.
 *
 *   When a batch has weak reference to no more resources (ie. all the
 *   surfaces it rendered to are destroyed) the batch can be destroyed.
 *   Could happen in an app that renders and never uses the result.  More
 *   common scenario, I think, will be that some, but not all, of the
 *   surfaces are destroyed before the batch is submitted.
 *
 *   If (for example), batch writes to zsbuf but that surface is destroyed
 *   before batch is submitted, we can skip gmem2mem (but still need to
 *   alloc gmem space as before.  If the batch depended on previous contents
 *   of that surface, it would be holding a reference so the surface would
 *   not have been destroyed.
 */

struct key {
        uint32_t width, height, layers;
        uint16_t samples, num_surfs;
        struct fd_context *ctx;
        struct {
                struct pipe_resource *texture;
                union pipe_surface_desc u;
                uint16_t pos, format;
        } surf[0];
};

static struct key *
key_alloc(unsigned num_surfs)
{
        struct key *key =
                CALLOC_VARIANT_LENGTH_STRUCT(key, sizeof(key->surf[0]) * num_surfs);
        return key;
}

static uint32_t
key_hash(const void *_key)
{
        const struct key *key = _key;
        uint32_t hash = _mesa_fnv32_1a_offset_bias;
        hash = _mesa_fnv32_1a_accumulate_block(hash, key, offsetof(struct key, surf[0]));
        hash = _mesa_fnv32_1a_accumulate_block(hash, key->surf, sizeof(key->surf[0]) * key->num_surfs);
        return hash;
}

static bool
key_equals(const void *_a, const void *_b)
{
        const struct key *a = _a;
        const struct key *b = _b;
        return (memcmp(a, b, offsetof(struct key, surf[0])) == 0) &&
                (memcmp(a->surf, b->surf, sizeof(a->surf[0]) * a->num_surfs) == 0);
}

void
fd_bc_init(struct fd_batch_cache *cache)
{
        cache->ht = _mesa_hash_table_create(NULL, key_hash, key_equals);
}

void
fd_bc_fini(struct fd_batch_cache *cache)
{
        _mesa_hash_table_destroy(cache->ht, NULL);
}

static void
bc_flush(struct fd_batch_cache *cache, struct fd_context *ctx, bool deferred)
{
        /* fd_batch_flush() (and fd_batch_add_dep() which calls it indirectly)
         * can cause batches to be unref'd and freed under our feet, so grab
         * a reference to all the batches we need up-front.
         */
        struct fd_batch *batches[ARRAY_SIZE(cache->batches)] = {0};
        struct fd_batch *batch;
        unsigned n = 0;

        fd_context_lock(ctx);

        foreach_batch(batch, cache, cache->batch_mask) {
                if (batch->ctx == ctx) {
                        fd_batch_reference_locked(&batches[n++], batch);
                }
        }

        if (deferred) {
                struct fd_batch *current_batch = ctx->batch;

                for (unsigned i = 0; i < n; i++) {
                        if (batches[i] != current_batch) {
                                fd_batch_add_dep(current_batch, batches[i]);
                        }
                }

                fd_context_unlock(ctx);
        } else {
                fd_context_unlock(ctx);

                for (unsigned i = 0; i < n; i++) {
                        fd_batch_flush(batches[i], false, false);
                }
        }

        for (unsigned i = 0; i < n; i++) {
                fd_batch_reference(&batches[i], NULL);
        }
}

void
fd_bc_flush(struct fd_batch_cache *cache, struct fd_context *ctx)
{
        bc_flush(cache, ctx, false);
}

/* deferred flush doesn't actually flush, but it marks every other
 * batch associated with the context as dependent on the current
 * batch.  So when the current batch gets flushed, all other batches
 * that came before also get flushed.
 */
void
fd_bc_flush_deferred(struct fd_batch_cache *cache, struct fd_context *ctx)
{
        bc_flush(cache, ctx, true);
}

void
fd_bc_invalidate_context(struct fd_context *ctx)
{
        struct fd_batch_cache *cache = &ctx->screen->batch_cache;
        struct fd_batch *batch;

        mtx_lock(&ctx->screen->lock);

        foreach_batch(batch, cache, cache->batch_mask) {
                if (batch->ctx == ctx)
                        fd_bc_invalidate_batch(batch, true);
        }

        mtx_unlock(&ctx->screen->lock);
}

void
fd_bc_invalidate_batch(struct fd_batch *batch, bool destroy)
{
        if (!batch)
                return;

        struct fd_batch_cache *cache = &batch->ctx->screen->batch_cache;
        struct key *key = (struct key *)batch->key;

        pipe_mutex_assert_locked(batch->ctx->screen->lock);

        if (destroy) {
                cache->batches[batch->idx] = NULL;
                cache->batch_mask &= ~(1 << batch->idx);
        }

        if (!key)
                return;

        DBG("%p: key=%p", batch, batch->key);
        for (unsigned idx = 0; idx < key->num_surfs; idx++) {
                struct fd_resource *rsc = fd_resource(key->surf[idx].texture);
                rsc->bc_batch_mask &= ~(1 << batch->idx);
        }

        struct hash_entry *entry =
                _mesa_hash_table_search_pre_hashed(cache->ht, batch->hash, key);
        _mesa_hash_table_remove(cache->ht, entry);

        batch->key = NULL;
        free(key);
}

void
fd_bc_invalidate_resource(struct fd_resource *rsc, bool destroy)
{
        struct fd_screen *screen = fd_screen(rsc->base.screen);
        struct fd_batch *batch;

        mtx_lock(&screen->lock);

        if (destroy) {
                foreach_batch(batch, &screen->batch_cache, rsc->batch_mask) {
                        struct set_entry *entry = _mesa_set_search(batch->resources, rsc);
                        _mesa_set_remove(batch->resources, entry);
                }
                rsc->batch_mask = 0;

                fd_batch_reference_locked(&rsc->write_batch, NULL);
        }

        foreach_batch(batch, &screen->batch_cache, rsc->bc_batch_mask)
                fd_bc_invalidate_batch(batch, false);

        rsc->bc_batch_mask = 0;

        mtx_unlock(&screen->lock);
}

struct fd_batch *
fd_bc_alloc_batch(struct fd_batch_cache *cache, struct fd_context *ctx)
{
        struct fd_batch *batch;
        uint32_t idx;

        mtx_lock(&ctx->screen->lock);

        while ((idx = ffs(~cache->batch_mask)) == 0) {
#if 0
                for (unsigned i = 0; i < ARRAY_SIZE(cache->batches); i++) {
                        batch = cache->batches[i];
                        debug_printf("%d: needs_flush=%d, depends:", batch->idx, batch->needs_flush);
                        struct set_entry *entry;
                        set_foreach(batch->dependencies, entry) {
                                struct fd_batch *dep = (struct fd_batch *)entry->key;
                                debug_printf(" %d", dep->idx);
                        }
                        debug_printf("\n");
                }
#endif
                /* TODO: is LRU the better policy?  Or perhaps the batch that
                 * depends on the fewest other batches?
                 */
                struct fd_batch *flush_batch = NULL;
                for (unsigned i = 0; i < ARRAY_SIZE(cache->batches); i++) {
                        if ((cache->batches[i] == ctx->batch) ||
                                        !cache->batches[i]->needs_flush)
                                continue;
                        if (!flush_batch || (cache->batches[i]->seqno < flush_batch->seqno))
                                fd_batch_reference_locked(&flush_batch, cache->batches[i]);
                }

                /* we can drop lock temporarily here, since we hold a ref,
                 * flush_batch won't disappear under us.
                 */
                mtx_unlock(&ctx->screen->lock);
                DBG("%p: too many batches!  flush forced!", flush_batch);
                fd_batch_flush(flush_batch, true, false);
                mtx_lock(&ctx->screen->lock);

                /* While the resources get cleaned up automatically, the flush_batch
                 * doesn't get removed from the dependencies of other batches, so
                 * it won't be unref'd and will remain in the table.
                 *
                 * TODO maybe keep a bitmask of batches that depend on me, to make
                 * this easier:
                 */
                for (unsigned i = 0; i < ARRAY_SIZE(cache->batches); i++) {
                        struct fd_batch *other = cache->batches[i];
                        if (!other)
                                continue;
                        if (other->dependents_mask & (1 << flush_batch->idx)) {
                                other->dependents_mask &= ~(1 << flush_batch->idx);
                                struct fd_batch *ref = flush_batch;
                                fd_batch_reference_locked(&ref, NULL);
                        }
                }

                fd_batch_reference_locked(&flush_batch, NULL);
        }

        idx--;              /* bit zero returns 1 for ffs() */

        batch = fd_batch_create(ctx, false);
        if (!batch)
                goto out;

        batch->seqno = cache->cnt++;
        batch->idx = idx;
        cache->batch_mask |= (1 << idx);

        debug_assert(cache->batches[idx] == NULL);
        cache->batches[idx] = batch;

out:
        mtx_unlock(&ctx->screen->lock);

        return batch;
}

static struct fd_batch *
batch_from_key(struct fd_batch_cache *cache, struct key *key,
                struct fd_context *ctx)
{
        struct fd_batch *batch = NULL;
        uint32_t hash = key_hash(key);
        struct hash_entry *entry =
                _mesa_hash_table_search_pre_hashed(cache->ht, hash, key);

        if (entry) {
                free(key);
                fd_batch_reference(&batch, (struct fd_batch *)entry->data);
                return batch;
        }

        batch = fd_bc_alloc_batch(cache, ctx);
#ifdef DEBUG
        DBG("%p: hash=0x%08x, %ux%u, %u layers, %u samples", batch, hash,
                        key->width, key->height, key->layers, key->samples);
        for (unsigned idx = 0; idx < key->num_surfs; idx++) {
                DBG("%p:  surf[%u]: %p (%s) (%u,%u / %u,%u,%u)", batch, key->surf[idx].pos,
                        key->surf[idx].texture, util_format_name(key->surf[idx].format),
                        key->surf[idx].u.buf.first_element, key->surf[idx].u.buf.last_element,
                        key->surf[idx].u.tex.first_layer, key->surf[idx].u.tex.last_layer,
                        key->surf[idx].u.tex.level);
        }
#endif
        if (!batch)
                return NULL;

        mtx_lock(&ctx->screen->lock);

        _mesa_hash_table_insert_pre_hashed(cache->ht, hash, key, batch);
        batch->key = key;
        batch->hash = hash;

        for (unsigned idx = 0; idx < key->num_surfs; idx++) {
                struct fd_resource *rsc = fd_resource(key->surf[idx].texture);
                rsc->bc_batch_mask = (1 << batch->idx);
        }

        mtx_unlock(&ctx->screen->lock);

        return batch;
}

static void
key_surf(struct key *key, unsigned idx, unsigned pos, struct pipe_surface *psurf)
{
        key->surf[idx].texture = psurf->texture;
        key->surf[idx].u = psurf->u;
        key->surf[idx].pos = pos;
        key->surf[idx].format = psurf->format;
}

struct fd_batch *
fd_batch_from_fb(struct fd_batch_cache *cache, struct fd_context *ctx,
                const struct pipe_framebuffer_state *pfb)
{
        unsigned idx = 0, n = pfb->nr_cbufs + (pfb->zsbuf ? 1 : 0);
        struct key *key = key_alloc(n);

        key->width = pfb->width;
        key->height = pfb->height;
        key->layers = pfb->layers;
        key->samples = pfb->samples;
        key->ctx = ctx;

        if (pfb->zsbuf)
                key_surf(key, idx++, 0, pfb->zsbuf);

        for (unsigned i = 0; i < pfb->nr_cbufs; i++)
                if (pfb->cbufs[i])
                        key_surf(key, idx++, i + 1, pfb->cbufs[i]);

        key->num_surfs = idx;

        return batch_from_key(cache, key, ctx);
}