diff options
| -rw-r--r-- | io_uring/kbuf.c | 77 |
1 files changed, 66 insertions, 11 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 85e680fc74ce..325ca7f8b0a0 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -36,6 +36,8 @@ struct io_provide_buf { struct io_buf_free { struct hlist_node list; void *mem; + size_t size; + int inuse; }; static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, @@ -216,6 +218,24 @@ static __cold int io_init_bl_list(struct io_ring_ctx *ctx) return 0; } +/* + * Mark the given mapped range as free for reuse + */ +static void io_kbuf_mark_free(struct io_ring_ctx *ctx, struct io_buffer_list *bl) +{ + struct io_buf_free *ibf; + + hlist_for_each_entry(ibf, &ctx->io_buf_list, list) { + if (bl->buf_ring == ibf->mem) { + ibf->inuse = 0; + return; + } + } + + /* can't happen... */ + WARN_ON_ONCE(1); +} + static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned nbufs) { @@ -232,6 +252,7 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, * io_kbuf_list_free() will free the page(s) at * ->release() time. */ + io_kbuf_mark_free(ctx, bl); bl->buf_ring = NULL; bl->is_mmap = 0; } else if (bl->buf_nr_pages) { @@ -539,6 +560,34 @@ error_unpin: return -EINVAL; } +/* + * See if we have a suitable region that we can reuse, rather than allocate + * both a new io_buf_free and mem region again. We leave it on the list as + * even a reused entry will need freeing at ring release. + */ +static struct io_buf_free *io_lookup_buf_free_entry(struct io_ring_ctx *ctx, + size_t ring_size) +{ + struct io_buf_free *ibf, *best = NULL; + size_t best_dist; + + hlist_for_each_entry(ibf, &ctx->io_buf_list, list) { + size_t dist; + + if (ibf->inuse || ibf->size < ring_size) + continue; + dist = ibf->size - ring_size; + if (!best || dist < best_dist) { + best = ibf; + if (!dist) + break; + best_dist = dist; + } + } + + return best; +} + static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx, struct io_uring_buf_reg *reg, struct io_buffer_list *bl) @@ -548,20 +597,26 @@ static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx, void *ptr; ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring); - ptr = io_mem_alloc(ring_size); - if (!ptr) - return -ENOMEM; - /* Allocate and store deferred free entry */ - ibf = kmalloc(sizeof(*ibf), GFP_KERNEL_ACCOUNT); + /* Reuse existing entry, if we can */ + ibf = io_lookup_buf_free_entry(ctx, ring_size); if (!ibf) { - io_mem_free(ptr); - return -ENOMEM; - } - ibf->mem = ptr; - hlist_add_head(&ibf->list, &ctx->io_buf_list); + ptr = io_mem_alloc(ring_size); + if (!ptr) + return -ENOMEM; - bl->buf_ring = ptr; + /* Allocate and store deferred free entry */ + ibf = kmalloc(sizeof(*ibf), GFP_KERNEL_ACCOUNT); + if (!ibf) { + io_mem_free(ptr); + return -ENOMEM; + } + ibf->mem = ptr; + ibf->size = ring_size; + hlist_add_head(&ibf->list, &ctx->io_buf_list); + } + ibf->inuse = 1; + bl->buf_ring = ibf->mem; bl->is_mapped = 1; bl->is_mmap = 1; return 0; |