RDS: Use page_remainder_alloc() for recv bufs
Instead of splitting up a page into RDS_FRAG_SIZE chunks ourselves, ask rds_page_remainder_alloc() to do it. While it is possible PAGE_SIZE > FRAG_SIZE, on x86en it isn't, so having duplicate "carve up a page into buffers" code seems excessive. The other modification this spawns is the use of a single struct scatterlist in rds_page_frag instead of a bare page ptr. This causes verbosity to increase in some places, and decrease in others. Finally, I decided to unify the lifetimes and alloc/free of rds_page_frag and its page. This is a nice simplification in itself, but will be extra-nice once we come to adding cmason's recycling patch. Signed-off-by: Andy Grover <andy.grover@oracle.com>
This commit is contained in:
Andy Grover
Родитель
fc19de38be
Коммит
0b088e003c
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@ -28,13 +28,9 @@ extern struct list_head rds_ib_devices;
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* try and minimize the amount of memory tied up both the device and
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* socket receive queues.
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*/
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/* page offset of the final full frag that fits in the page */
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#define RDS_PAGE_LAST_OFF (((PAGE_SIZE / RDS_FRAG_SIZE) - 1) * RDS_FRAG_SIZE)
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struct rds_page_frag {
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struct list_head f_item;
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struct page *f_page;
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unsigned long f_offset;
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dma_addr_t f_mapped;
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struct scatterlist f_sg;
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};
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struct rds_ib_incoming {
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@ -107,7 +103,6 @@ struct rds_ib_connection {
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struct rds_header *i_recv_hdrs;
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u64 i_recv_hdrs_dma;
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struct rds_ib_recv_work *i_recvs;
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struct rds_page_frag i_frag;
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u64 i_ack_recv; /* last ACK received */
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/* sending acks */
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@ -43,17 +43,11 @@ static struct kmem_cache *rds_ib_incoming_slab;
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static struct kmem_cache *rds_ib_frag_slab;
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static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
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static void rds_ib_frag_drop_page(struct rds_page_frag *frag)
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{
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rdsdebug("frag %p page %p\n", frag, frag->f_page);
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__free_page(frag->f_page);
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frag->f_page = NULL;
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}
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/* Free frag and attached recv buffer f_sg */
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static void rds_ib_frag_free(struct rds_page_frag *frag)
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{
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rdsdebug("frag %p page %p\n", frag, frag->f_page);
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BUG_ON(frag->f_page);
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rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
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__free_page(sg_page(&frag->f_sg));
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kmem_cache_free(rds_ib_frag_slab, frag);
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}
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@ -71,12 +65,8 @@ static void rds_ib_recv_unmap_page(struct rds_ib_connection *ic,
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{
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struct rds_page_frag *frag = recv->r_frag;
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rdsdebug("recv %p frag %p page %p\n", recv, frag, frag->f_page);
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if (frag->f_mapped)
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ib_dma_unmap_page(ic->i_cm_id->device,
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frag->f_mapped,
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RDS_FRAG_SIZE, DMA_FROM_DEVICE);
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frag->f_mapped = 0;
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rdsdebug("recv %p frag %p page %p\n", recv, frag, sg_page(&frag->f_sg));
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ib_dma_unmap_sg(ic->i_cm_id->device, &frag->f_sg, 1, DMA_FROM_DEVICE);
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}
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void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
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@ -116,8 +106,6 @@ static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
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}
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if (recv->r_frag) {
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rds_ib_recv_unmap_page(ic, recv);
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if (recv->r_frag->f_page)
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rds_ib_frag_drop_page(recv->r_frag);
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rds_ib_frag_free(recv->r_frag);
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recv->r_frag = NULL;
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}
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@ -129,16 +117,12 @@ void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
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for (i = 0; i < ic->i_recv_ring.w_nr; i++)
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rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
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if (ic->i_frag.f_page)
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rds_ib_frag_drop_page(&ic->i_frag);
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}
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static int rds_ib_recv_refill_one(struct rds_connection *conn,
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struct rds_ib_recv_work *recv)
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{
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struct rds_ib_connection *ic = conn->c_transport_data;
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dma_addr_t dma_addr;
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struct ib_sge *sge;
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int ret = -ENOMEM;
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@ -161,50 +145,27 @@ static int rds_ib_recv_refill_one(struct rds_connection *conn,
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if (!recv->r_frag)
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goto out;
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INIT_LIST_HEAD(&recv->r_frag->f_item);
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recv->r_frag->f_page = NULL;
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}
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if (!ic->i_frag.f_page) {
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ic->i_frag.f_page = alloc_page(GFP_NOWAIT);
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if (!ic->i_frag.f_page)
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sg_init_table(&recv->r_frag->f_sg, 1);
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ret = rds_page_remainder_alloc(&recv->r_frag->f_sg,
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RDS_FRAG_SIZE, GFP_NOWAIT);
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if (ret) {
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kmem_cache_free(rds_ib_frag_slab, recv->r_frag);
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recv->r_frag = NULL;
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goto out;
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ic->i_frag.f_offset = 0;
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}
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}
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dma_addr = ib_dma_map_page(ic->i_cm_id->device,
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ic->i_frag.f_page,
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ic->i_frag.f_offset,
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RDS_FRAG_SIZE,
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DMA_FROM_DEVICE);
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if (ib_dma_mapping_error(ic->i_cm_id->device, dma_addr))
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goto out;
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/*
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* Once we get the RDS_PAGE_LAST_OFF frag then rds_ib_frag_unmap()
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* must be called on this recv. This happens as completions hit
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* in order or on connection shutdown.
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*/
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recv->r_frag->f_page = ic->i_frag.f_page;
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recv->r_frag->f_offset = ic->i_frag.f_offset;
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recv->r_frag->f_mapped = dma_addr;
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ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
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1, DMA_FROM_DEVICE);
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WARN_ON(ret != 1);
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sge = &recv->r_sge[0];
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sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
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sge->length = sizeof(struct rds_header);
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sge = &recv->r_sge[1];
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sge->addr = dma_addr;
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sge->length = RDS_FRAG_SIZE;
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get_page(recv->r_frag->f_page);
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if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) {
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ic->i_frag.f_offset += RDS_FRAG_SIZE;
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} else {
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put_page(ic->i_frag.f_page);
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ic->i_frag.f_page = NULL;
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ic->i_frag.f_offset = 0;
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}
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sge->addr = sg_dma_address(&recv->r_frag->f_sg);
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sge->length = sg_dma_len(&recv->r_frag->f_sg);
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ret = 0;
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out:
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@ -247,8 +208,8 @@ int rds_ib_recv_refill(struct rds_connection *conn, int prefill)
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/* XXX when can this fail? */
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ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
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rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
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recv->r_ibinc, recv->r_frag->f_page,
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(long) recv->r_frag->f_mapped, ret);
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recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
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(long) sg_dma_address(&recv->r_frag->f_sg), ret);
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if (ret) {
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rds_ib_conn_error(conn, "recv post on "
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"%pI4 returned %d, disconnecting and "
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@ -281,7 +242,6 @@ static void rds_ib_inc_purge(struct rds_incoming *inc)
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list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
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list_del_init(&frag->f_item);
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rds_ib_frag_drop_page(frag);
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rds_ib_frag_free(frag);
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}
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}
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@ -333,13 +293,13 @@ int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
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to_copy = min_t(unsigned long, to_copy, len - copied);
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rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
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"[%p, %lu] + %lu\n",
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"[%p, %u] + %lu\n",
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to_copy, iov->iov_base, iov->iov_len, iov_off,
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frag->f_page, frag->f_offset, frag_off);
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sg_page(&frag->f_sg), frag->f_sg.offset, frag_off);
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/* XXX needs + offset for multiple recvs per page */
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ret = rds_page_copy_to_user(frag->f_page,
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frag->f_offset + frag_off,
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ret = rds_page_copy_to_user(sg_page(&frag->f_sg),
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frag->f_sg.offset + frag_off,
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iov->iov_base + iov_off,
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to_copy);
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if (ret) {
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@ -595,7 +555,7 @@ static void rds_ib_cong_recv(struct rds_connection *conn,
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to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
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BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
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addr = kmap_atomic(frag->f_page, KM_SOFTIRQ0);
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addr = kmap_atomic(sg_page(&frag->f_sg), KM_SOFTIRQ0);
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src = addr + frag_off;
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dst = (void *)map->m_page_addrs[map_page] + map_off;
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@ -698,12 +658,12 @@ static void rds_ib_process_recv(struct rds_connection *conn,
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* the inc is freed. We don't go that route, so we have to drop the
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* page ref ourselves. We can't just leave the page on the recv
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* because that confuses the dma mapping of pages and each recv's use
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* of a partial page. We can leave the frag, though, it will be
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* reused.
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* of a partial page.
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*
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* FIXME: Fold this into the code path below.
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*/
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rds_ib_frag_drop_page(recv->r_frag);
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rds_ib_frag_free(recv->r_frag);
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recv->r_frag = NULL;
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return;
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}
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@ -186,6 +186,7 @@ out:
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ret ? 0 : scat->length);
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return ret;
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}
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EXPORT_SYMBOL_GPL(rds_page_remainder_alloc);
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static int rds_page_remainder_cpu_notify(struct notifier_block *self,
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unsigned long action, void *hcpu)
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