David Gwynne wrote:
> this adds a pool backend for MCLGETI thats 2k+2 bytes in size, which
> can be used on some very common nics that have annoying constraints
> on their rx descriptors.
>
> this in turn simplifies the code in those drivers and lets them
> always operate on ETHER_ALIGN boundaries.
>
> the pool is cheap, pages will only be allocated in it if something
> asks for them, and it keeps this complexity out of the drivers.
pool is efficient, but it can't work miracles. on archs like amd64, this is
going to only pack 15 clusters in a 32k "page" instead of 16.
if i understand correctly, currently em is using 4k clusters on strict
alignment? i think it makes a lot of sense to add a 2k2 pool because that
means using less memory. but not strict alignment shouldn't be forced to use
more memory. that's a regression.
>
> ok?
>
> Index: net/if.h
> ===================================================================
> RCS file: /cvs/src/sys/net/if.h,v
> retrieving revision 1.179
> diff -u -p -r1.179 if.h
> --- net/if.h 4 Sep 2016 15:10:59 -0000 1.179
> +++ net/if.h 14 Oct 2016 03:46:22 -0000
> @@ -68,7 +68,7 @@ struct if_clonereq {
> char *ifcr_buffer; /* buffer for cloner names */
> };
>
> -#define MCLPOOLS 7 /* number of cluster pools */
> +#define MCLPOOLS 8 /* number of cluster pools */
>
> struct if_rxring {
> int rxr_adjusted;
> Index: kern/uipc_mbuf.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/uipc_mbuf.c,v
> retrieving revision 1.233
> diff -u -p -r1.233 uipc_mbuf.c
> --- kern/uipc_mbuf.c 10 Oct 2016 00:41:17 -0000 1.233
> +++ kern/uipc_mbuf.c 14 Oct 2016 03:46:22 -0000
> @@ -107,6 +107,7 @@ struct pool mtagpool;
> /* mbuf cluster pools */
> u_int mclsizes[MCLPOOLS] = {
> MCLBYTES, /* must be at slot 0 */
> + MCLBYTES + 2, /* ETHER_ALIGNED 2k mbufs */
> 4 * 1024,
> 8 * 1024,
> 9 * 1024,
> @@ -142,6 +143,7 @@ void
> mbinit(void)
> {
> int i;
> + unsigned int lowbits;
>
> #if DIAGNOSTIC
> if (mclsizes[0] != MCLBYTES)
> @@ -158,9 +160,15 @@ mbinit(void)
> IPL_NET, 0, "mtagpl", NULL);
>
> for (i = 0; i < nitems(mclsizes); i++) {
> - snprintf(mclnames[i], sizeof(mclnames[0]), "mcl%dk",
> - mclsizes[i] >> 10);
> - pool_init(&mclpools[i], mclsizes[i], 0, IPL_NET, 0,
> + lowbits = mclsizes[i] & ((1 << 10) - 1);
> + if (lowbits) {
> + snprintf(mclnames[i], sizeof(mclnames[0]),
> + "mcl%dk%u", mclsizes[i] >> 10, lowbits);
> + } else {
> + snprintf(mclnames[i], sizeof(mclnames[0]), "mcl%dk",
> + mclsizes[i] >> 10);
> + }
> + pool_init(&mclpools[i], mclsizes[i], 64, IPL_NET, 0,
> mclnames[i], NULL);
> pool_set_constraints(&mclpools[i], &kp_dma_contig);
> pool_setlowat(&mclpools[i], mcllowat);
> Index: dev/pci/if_em.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_em.c,v
> retrieving revision 1.331
> diff -u -p -r1.331 if_em.c
> --- dev/pci/if_em.c 13 Apr 2016 10:34:32 -0000 1.331
> +++ dev/pci/if_em.c 14 Oct 2016 03:47:21 -0000
> @@ -2450,9 +2450,7 @@ em_get_buf(struct em_softc *sc, int i)
> return (ENOBUFS);
> }
> m->m_len = m->m_pkthdr.len = EM_MCLBYTES;
> -#ifdef __STRICT_ALIGNMENT
> m_adj(m, ETHER_ALIGN);
> -#endif
>
> error = bus_dmamap_load_mbuf(sc->sc_dmat, pkt->pkt_map,
> m, BUS_DMA_NOWAIT);
> Index: dev/pci/if_ix.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_ix.c,v
> retrieving revision 1.132
> diff -u -p -r1.132 if_ix.c
> --- dev/pci/if_ix.c 13 Apr 2016 10:34:32 -0000 1.132
> +++ dev/pci/if_ix.c 14 Oct 2016 03:47:21 -0000
> @@ -616,11 +616,7 @@ ixgbe_init(void *arg)
> ixgbe_initialize_transmit_units(sc);
>
> /* Use 2k clusters, even for jumbo frames */
> -#ifdef __STRICT_ALIGNMENT
> sc->rx_mbuf_sz = MCLBYTES + ETHER_ALIGN;
> -#else
> - sc->rx_mbuf_sz = MCLBYTES;
> -#endif
>
> /* Prepare receive descriptors and buffers */
> if (ixgbe_setup_receive_structures(sc)) {
> @@ -2458,9 +2454,7 @@ ixgbe_get_buf(struct rx_ring *rxr, int i
> return (ENOBUFS);
>
> mp->m_len = mp->m_pkthdr.len = sc->rx_mbuf_sz;
> -#ifdef __STRICT_ALIGNMENT
> m_adj(mp, ETHER_ALIGN);
> -#endif
>
> error = bus_dmamap_load_mbuf(rxr->rxdma.dma_tag, rxbuf->map,
> mp, BUS_DMA_NOWAIT);
> @@ -2667,11 +2661,7 @@ ixgbe_initialize_receive_units(struct ix
> hlreg |= IXGBE_HLREG0_JUMBOEN;
> IXGBE_WRITE_REG(&sc->hw, IXGBE_HLREG0, hlreg);
>
> -#ifdef __STRICT_ALIGNMENT
> bufsz = (sc->rx_mbuf_sz - ETHER_ALIGN) >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
> -#else
> - bufsz = sc->rx_mbuf_sz >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
> -#endif
>
> for (i = 0; i < sc->num_queues; i++, rxr++) {
> uint64_t rdba = rxr->rxdma.dma_map->dm_segs[0].ds_addr;
> Index: dev/pci/if_em.h
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_em.h,v
> retrieving revision 1.72
> diff -u -p -r1.72 if_em.h
> --- dev/pci/if_em.h 18 Feb 2016 14:24:39 -0000 1.72
> +++ dev/pci/if_em.h 14 Oct 2016 03:48:32 -0000
> @@ -263,11 +263,7 @@ typedef int boolean_t;
> #define EM_RXBUFFER_8192 8192
> #define EM_RXBUFFER_16384 16384
>
> -#ifdef __STRICT_ALIGNMENT
> #define EM_MCLBYTES (EM_RXBUFFER_2048 + ETHER_ALIGN)
> -#else
> -#define EM_MCLBYTES EM_RXBUFFER_2048
> -#endif
>
> #define EM_MAX_SCATTER 64
> #define EM_TSO_SIZE 65535
>
