freebsd-dev/sys/dev/iscsi/icl_wrappers.h
Alexander Motin 9a4510ac32 Implement zero-copy iSCSI target transmission/read.
Add ICL_NOCOPY flag to icl_pdu_append_data(), specifying that the method
can just reference the data buffer instead of immediately copying it.

Extend the offload KPI with optional PDU queue method, allowing to specify
completion callback, called when all the data referenced by above has been
transferred and won't be accessed any more (the buffers can be freed).

Implement the above functionality in software iSCSI driver using mbufs
with external storage and reference counter.  Note that some NICs (ixl(4))
may keep the mbuf in TX queue for a long time, so CTL has to be ready.

Add optional method to struct ctl_scsiio for buffer reference counting.
Implement it for CTL block backend, allowing to delay free of the struct
ctl_be_block_io and memory it references as needed.  In first reincarnation
of the patch I tried to delay whole I/O as it is done for FibreChannel,
that was cleaner, but due to the above callback delays I had to rewrite
it this way to not leave LUN referenced potentially for hours or more.

All together on sequential read from ZFS ARC this saves about 30% of CPU
time and memory bandwidth by avoiding one of 3 memory copies (the other
two are from ZFS ARC to DMU cache and then from DMU cache to CTL buffers).
On tests with 2x Xeon Silver 4114 this allows to reach full line rate of
100GigE NIC.  Tests with Gold CPUs and two 100GigE NICs are stil TBD,
but expectations to saturate them are pretty high. ;)

Discussed with:	Chelsio
Sponsored by:	iXsystems, Inc.
2020-06-08 20:53:57 +00:00

160 lines
3.9 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* This file is used to provide the initiator and target with a prettier
* interface. It must not be included by ICL modules, such as icl_soft.c.
*/
#ifndef ICL_WRAPPERS_H
#define ICL_WRAPPERS_H
#include <sys/kobj.h>
#include <dev/iscsi/icl.h>
#include <icl_conn_if.h>
static inline struct icl_pdu *
icl_pdu_new(struct icl_conn *ic, int flags)
{
return (ICL_CONN_NEW_PDU(ic, flags));
}
static inline size_t
icl_pdu_data_segment_length(const struct icl_pdu *ip)
{
return (ICL_CONN_PDU_DATA_SEGMENT_LENGTH(ip->ip_conn, ip));
}
static inline int
icl_pdu_append_data(struct icl_pdu *ip, const void *addr, size_t len, int flags)
{
return (ICL_CONN_PDU_APPEND_DATA(ip->ip_conn, ip, addr, len, flags));
}
static inline void
icl_pdu_get_data(struct icl_pdu *ip, size_t off, void *addr, size_t len)
{
ICL_CONN_PDU_GET_DATA(ip->ip_conn, ip, off, addr, len);
}
static inline void
icl_pdu_queue(struct icl_pdu *ip)
{
ICL_CONN_PDU_QUEUE(ip->ip_conn, ip);
}
static inline void
icl_pdu_queue_cb(struct icl_pdu *ip, icl_pdu_cb cb)
{
ICL_CONN_PDU_QUEUE_CB(ip->ip_conn, ip, cb);
}
static inline void
icl_pdu_free(struct icl_pdu *ip)
{
ICL_CONN_PDU_FREE(ip->ip_conn, ip);
}
static inline void
icl_conn_free(struct icl_conn *ic)
{
ICL_CONN_FREE(ic);
}
static inline int
icl_conn_handoff(struct icl_conn *ic, int fd)
{
return (ICL_CONN_HANDOFF(ic, fd));
}
static inline void
icl_conn_close(struct icl_conn *ic)
{
ICL_CONN_CLOSE(ic);
}
static inline int
icl_conn_task_setup(struct icl_conn *ic, struct icl_pdu *ip,
struct ccb_scsiio *csio, uint32_t *task_tagp, void **prvp)
{
return (ICL_CONN_TASK_SETUP(ic, ip, csio, task_tagp, prvp));
}
static inline void
icl_conn_task_done(struct icl_conn *ic, void *prv)
{
ICL_CONN_TASK_DONE(ic, prv);
}
static inline int
icl_conn_transfer_setup(struct icl_conn *ic, union ctl_io *io,
uint32_t *transfer_tagp, void **prvp)
{
return (ICL_CONN_TRANSFER_SETUP(ic, io, transfer_tagp, prvp));
}
static inline void
icl_conn_transfer_done(struct icl_conn *ic, void *prv)
{
ICL_CONN_TRANSFER_DONE(ic, prv);
}
/*
* The function below is only used with ICL_KERNEL_PROXY.
*/
static inline int
icl_conn_connect(struct icl_conn *ic, int domain, int socktype,
int protocol, struct sockaddr *from_sa, struct sockaddr *to_sa)
{
return (ICL_CONN_CONNECT(ic, domain, socktype, protocol,
from_sa, to_sa));
}
#endif /* !ICL_WRAPPERS_H */