From 5c198f660a1812d9b3970408695d04bdd74a5d1e Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jos=C3=A9=20Fonseca?= Date: Tue, 2 Sep 2008 02:16:43 +0900 Subject: [PATCH] pipebuffer: Comment the slab code. Remove the freeSlabs list. The freeSlabs list is not really needed as we free empty slabs immediately. Time based cached is done separately. --- .../auxiliary/pipebuffer/pb_bufmgr_slab.c | 104 +++++++++++++----- 1 file changed, 77 insertions(+), 27 deletions(-) diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c index ac0296b26a8..8698c4cff62 100644 --- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c +++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c @@ -30,6 +30,8 @@ * @file * S-lab pool implementation. * + * @sa http://en.wikipedia.org/wiki/Slab_allocation + * * @author Thomas Hellstrom * @author Jose Fonseca */ @@ -49,46 +51,96 @@ struct pb_slab; + +/** + * Buffer in a slab. + * + * Sub-allocation of a contiguous buffer. + */ struct pb_slab_buffer { struct pb_buffer base; struct pb_slab *slab; + struct list_head head; + unsigned mapCount; + + /** Offset relative to the start of the slab buffer. */ size_t start; + + /** Use when validating, to signal that all mappings are finished */ + /* TODO: Actually validation does not reach this stage yet */ pipe_condvar event; }; + +/** + * Slab -- a contiguous piece of memory. + */ struct pb_slab { struct list_head head; struct list_head freeBuffers; size_t numBuffers; size_t numFree; + struct pb_slab_buffer *buffers; struct pb_slab_manager *mgr; + /** Buffer from the provider */ struct pb_buffer *bo; + void *virtual; }; + +/** + * It adds/removes slabs as needed in order to meet the allocation/destruction + * of individual buffers. + */ struct pb_slab_manager { struct pb_manager base; + /** From where we get our buffers */ struct pb_manager *provider; + + /** Size of the buffers we hand on downstream */ size_t bufSize; + + /** Size of the buffers we request upstream */ size_t slabSize; + + /** + * Alignment, usage to be used to allocate the slab buffers. + * + * We can only provide buffers which are consistent (in alignment, usage) + * with this description. + */ struct pb_desc desc; + /** + * Partial slabs + * + * Full slabs are not stored in any list. Empty slabs are destroyed + * immediatly. + */ struct list_head slabs; - struct list_head freeSlabs; pipe_mutex mutex; }; + /** + * Wrapper around several slabs, therefore capable of handling buffers of + * multiple sizes. + * + * This buffer manager just dispatches buffer allocations to the appropriate slab + * manager, according to the requested buffer size, or by passes the slab + * managers altogether for even greater sizes. + * * The data of this structure remains constant after * initialization and thus needs no mutex protection. */ @@ -97,12 +149,17 @@ struct pb_slab_range_manager struct pb_manager base; struct pb_manager *provider; + size_t minBufSize; size_t maxBufSize; + + /** @sa pb_slab_manager::desc */ struct pb_desc desc; unsigned numBuckets; size_t *bucketSizes; + + /** Array of pb_slab_manager, one for each bucket size */ struct pb_manager **buckets; }; @@ -156,29 +213,15 @@ pb_slab_buffer_destroy(struct pb_buffer *_buf) if (slab->head.next == &slab->head) LIST_ADDTAIL(&slab->head, &mgr->slabs); + /* If the slab becomes totally empty, free it */ if (slab->numFree == slab->numBuffers) { list = &slab->head; - LIST_DEL(list); - LIST_ADDTAIL(list, &mgr->freeSlabs); + LIST_DELINIT(list); + pb_reference(&slab->bo, NULL); + FREE(slab->buffers); + FREE(slab); } - if (mgr->slabs.next == &mgr->slabs || slab->numFree - != slab->numBuffers) { - - struct list_head *next; - - for (list = mgr->freeSlabs.next, next = list->next; list - != &mgr->freeSlabs; list = next, next = list->next) { - - slab = LIST_ENTRY(struct pb_slab, list, head); - - LIST_DELINIT(list); - pb_reference(&slab->bo, NULL); - FREE(slab->buffers); - FREE(slab); - } - } - pipe_mutex_unlock(mgr->mutex); } @@ -225,6 +268,11 @@ pb_slab_buffer_vtbl = { }; +/** + * Create a new slab. + * + * Called when we ran out of free slabs. + */ static enum pipe_error pb_slab_create(struct pb_slab_manager *mgr) { @@ -238,17 +286,14 @@ pb_slab_create(struct pb_slab_manager *mgr) if (!slab) return PIPE_ERROR_OUT_OF_MEMORY; - /* - * FIXME: We should perhaps allow some variation in slabsize in order - * to efficiently reuse slabs. - */ - slab->bo = mgr->provider->create_buffer(mgr->provider, mgr->slabSize, &mgr->desc); if(!slab->bo) { ret = PIPE_ERROR_OUT_OF_MEMORY; goto out_err0; } + /* Note down the slab virtual address. All mappings are accessed directly + * through this address so it is required that the buffer is pinned. */ slab->virtual = pb_map(slab->bo, PIPE_BUFFER_USAGE_CPU_READ | PIPE_BUFFER_USAGE_CPU_WRITE); @@ -256,7 +301,6 @@ pb_slab_create(struct pb_slab_manager *mgr) ret = PIPE_ERROR_OUT_OF_MEMORY; goto out_err1; } - pb_unmap(slab->bo); numBuffers = slab->bo->base.size / mgr->bufSize; @@ -289,6 +333,7 @@ pb_slab_create(struct pb_slab_manager *mgr) buf++; } + /* Add this slab to the list of partial slabs */ LIST_ADDTAIL(&slab->head, &mgr->slabs); return PIPE_OK; @@ -329,6 +374,8 @@ pb_slab_manager_create_buffer(struct pb_manager *_mgr, return NULL; pipe_mutex_lock(mgr->mutex); + + /* Create a new slab, if we run out of partial slabs */ if (mgr->slabs.next == &mgr->slabs) { (void) pb_slab_create(mgr); if (mgr->slabs.next == &mgr->slabs) { @@ -336,8 +383,12 @@ pb_slab_manager_create_buffer(struct pb_manager *_mgr, return NULL; } } + + /* Allocate the buffer from a partial (or just created) slab */ list = mgr->slabs.next; slab = LIST_ENTRY(struct pb_slab, list, head); + + /* If totally full remove from the partial slab list */ if (--slab->numFree == 0) LIST_DELINIT(list); @@ -386,7 +437,6 @@ pb_slab_manager_create(struct pb_manager *provider, mgr->desc = *desc; LIST_INITHEAD(&mgr->slabs); - LIST_INITHEAD(&mgr->freeSlabs); pipe_mutex_init(mgr->mutex); -- 2.30.2