freebsd-dev/sys/kern/subr_bus_dma.c
Konstantin Belousov ee75e7de7b Implement the concept of the unmapped VMIO buffers, i.e. buffers which
do not map the b_pages pages into buffer_map KVA.  The use of the
unmapped buffers eliminate the need to perform TLB shootdown for
mapping on the buffer creation and reuse, greatly reducing the amount
of IPIs for shootdown on big-SMP machines and eliminating up to 25-30%
of the system time on i/o intensive workloads.

The unmapped buffer should be explicitely requested by the GB_UNMAPPED
flag by the consumer.  For unmapped buffer, no KVA reservation is
performed at all. The consumer might request unmapped buffer which
does have a KVA reserve, to manually map it without recursing into
buffer cache and blocking, with the GB_KVAALLOC flag.

When the mapped buffer is requested and unmapped buffer already
exists, the cache performs an upgrade, possibly reusing the KVA
reservation.

Unmapped buffer is translated into unmapped bio in g_vfs_strategy().
Unmapped bio carry a pointer to the vm_page_t array, offset and length
instead of the data pointer.  The provider which processes the bio
should explicitely specify a readiness to accept unmapped bio,
otherwise g_down geom thread performs the transient upgrade of the bio
request by mapping the pages into the new bio_transient_map KVA
submap.

The bio_transient_map submap claims up to 10% of the buffer map, and
the total buffer_map + bio_transient_map KVA usage stays the
same. Still, it could be manually tuned by kern.bio_transient_maxcnt
tunable, in the units of the transient mappings.  Eventually, the
bio_transient_map could be removed after all geom classes and drivers
can accept unmapped i/o requests.

Unmapped support can be turned off by the vfs.unmapped_buf_allowed
tunable, disabling which makes the buffer (or cluster) creation
requests to ignore GB_UNMAPPED and GB_KVAALLOC flags.  Unmapped
buffers are only enabled by default on the architectures where
pmap_copy_page() was implemented and tested.

In the rework, filesystem metadata is not the subject to maxbufspace
limit anymore. Since the metadata buffers are always mapped, the
buffers still have to fit into the buffer map, which provides a
reasonable (but practically unreachable) upper bound on it. The
non-metadata buffer allocations, both mapped and unmapped, is
accounted against maxbufspace, as before. Effectively, this means that
the maxbufspace is forced on mapped and unmapped buffers separately.
The pre-patch bufspace limiting code did not worked, because
buffer_map fragmentation does not allow the limit to be reached.

By Jeff Roberson request, the getnewbuf() function was split into
smaller single-purpose functions.

Sponsored by:	The FreeBSD Foundation
Discussed with:	jeff (previous version)
Tested by:	pho, scottl (previous version), jhb, bf
MFC after:	2 weeks
2013-03-19 14:13:12 +00:00

478 lines
12 KiB
C

/*-
* Copyright (c) 2012 EMC Corp.
* All rights reserved.
*
* Copyright (c) 1997, 1998 Justin T. Gibbs.
* All rights reserved.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bus.h"
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/callout.h>
#include <sys/mbuf.h>
#include <sys/memdesc.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/pmap.h>
#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <machine/bus.h>
/*
* Load a list of virtual addresses.
*/
static int
_bus_dmamap_load_vlist(bus_dma_tag_t dmat, bus_dmamap_t map,
bus_dma_segment_t *list, int sglist_cnt, struct pmap *pmap, int *nsegs,
int flags)
{
int error;
error = 0;
for (; sglist_cnt > 0; sglist_cnt--, list++) {
error = _bus_dmamap_load_buffer(dmat, map,
(void *)list->ds_addr, list->ds_len, pmap, flags, NULL,
nsegs);
if (error)
break;
}
return (error);
}
/*
* Load a list of physical addresses.
*/
static int
_bus_dmamap_load_plist(bus_dma_tag_t dmat, bus_dmamap_t map,
bus_dma_segment_t *list, int sglist_cnt, int *nsegs, int flags)
{
int error;
error = 0;
for (; sglist_cnt > 0; sglist_cnt--, list++) {
error = _bus_dmamap_load_phys(dmat, map,
(vm_paddr_t)list->ds_addr, list->ds_len, flags, NULL,
nsegs);
if (error)
break;
}
return (error);
}
/*
* Load an mbuf chain.
*/
static int
_bus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map,
struct mbuf *m0, bus_dma_segment_t *segs, int *nsegs, int flags)
{
struct mbuf *m;
int error;
M_ASSERTPKTHDR(m0);
error = 0;
for (m = m0; m != NULL && error == 0; m = m->m_next) {
if (m->m_len > 0) {
error = _bus_dmamap_load_buffer(dmat, map, m->m_data,
m->m_len, kernel_pmap, flags | BUS_DMA_LOAD_MBUF,
segs, nsegs);
}
}
CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
__func__, dmat, flags, error, *nsegs);
return (error);
}
/*
* Load from block io.
*/
static int
_bus_dmamap_load_bio(bus_dma_tag_t dmat, bus_dmamap_t map, struct bio *bio,
int *nsegs, int flags)
{
vm_paddr_t paddr;
bus_size_t len, tlen;
int error, i, ma_offs;
if ((bio->bio_flags & BIO_UNMAPPED) == 0) {
error = _bus_dmamap_load_buffer(dmat, map, bio->bio_data,
bio->bio_bcount, kernel_pmap, flags, NULL, nsegs);
return (error);
}
error = 0;
tlen = bio->bio_bcount;
ma_offs = bio->bio_ma_offset;
for (i = 0; tlen > 0; i++, tlen -= len) {
len = min(PAGE_SIZE - ma_offs, tlen);
paddr = VM_PAGE_TO_PHYS(bio->bio_ma[i]) + ma_offs;
error = _bus_dmamap_load_phys(dmat, map, paddr, len,
flags, NULL, nsegs);
if (error != 0)
break;
ma_offs = 0;
}
return (error);
}
/*
* Load a cam control block.
*/
static int
_bus_dmamap_load_ccb(bus_dma_tag_t dmat, bus_dmamap_t map, union ccb *ccb,
int *nsegs, int flags)
{
struct ccb_ataio *ataio;
struct ccb_scsiio *csio;
struct ccb_hdr *ccb_h;
void *data_ptr;
int error;
uint32_t dxfer_len;
uint16_t sglist_cnt;
error = 0;
ccb_h = &ccb->ccb_h;
switch (ccb_h->func_code) {
case XPT_SCSI_IO:
csio = &ccb->csio;
data_ptr = csio->data_ptr;
dxfer_len = csio->dxfer_len;
sglist_cnt = csio->sglist_cnt;
break;
case XPT_ATA_IO:
ataio = &ccb->ataio;
data_ptr = ataio->data_ptr;
dxfer_len = ataio->dxfer_len;
sglist_cnt = 0;
break;
default:
panic("_bus_dmamap_load_ccb: Unsupported func code %d",
ccb_h->func_code);
}
switch ((ccb_h->flags & CAM_DATA_MASK)) {
case CAM_DATA_VADDR:
error = _bus_dmamap_load_buffer(dmat, map, data_ptr, dxfer_len,
kernel_pmap, flags, NULL, nsegs);
break;
case CAM_DATA_PADDR:
error = _bus_dmamap_load_phys(dmat, map,
(vm_paddr_t)(uintptr_t)data_ptr, dxfer_len, flags, NULL,
nsegs);
break;
case CAM_DATA_SG:
error = _bus_dmamap_load_vlist(dmat, map,
(bus_dma_segment_t *)data_ptr, sglist_cnt, kernel_pmap,
nsegs, flags);
break;
case CAM_DATA_SG_PADDR:
error = _bus_dmamap_load_plist(dmat, map,
(bus_dma_segment_t *)data_ptr, sglist_cnt, nsegs, flags);
break;
case CAM_DATA_BIO:
error = _bus_dmamap_load_bio(dmat, map, (struct bio *)data_ptr,
nsegs, flags);
break;
default:
panic("_bus_dmamap_load_ccb: flags 0x%X unimplemented",
ccb_h->flags);
}
return (error);
}
/*
* Load a uio.
*/
static int
_bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map, struct uio *uio,
int *nsegs, int flags)
{
bus_size_t resid;
bus_size_t minlen;
struct iovec *iov;
pmap_t pmap;
caddr_t addr;
int error, i;
if (uio->uio_segflg == UIO_USERSPACE) {
KASSERT(uio->uio_td != NULL,
("bus_dmamap_load_uio: USERSPACE but no proc"));
pmap = vmspace_pmap(uio->uio_td->td_proc->p_vmspace);
} else
pmap = kernel_pmap;
resid = uio->uio_resid;
iov = uio->uio_iov;
error = 0;
for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
/*
* Now at the first iovec to load. Load each iovec
* until we have exhausted the residual count.
*/
addr = (caddr_t) iov[i].iov_base;
minlen = resid < iov[i].iov_len ? resid : iov[i].iov_len;
if (minlen > 0) {
error = _bus_dmamap_load_buffer(dmat, map, addr,
minlen, pmap, flags, NULL, nsegs);
resid -= minlen;
}
}
return (error);
}
/*
* Map the buffer buf into bus space using the dmamap map.
*/
int
bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
bus_size_t buflen, bus_dmamap_callback_t *callback,
void *callback_arg, int flags)
{
bus_dma_segment_t *segs;
struct memdesc mem;
int error;
int nsegs;
if ((flags & BUS_DMA_NOWAIT) == 0) {
mem = memdesc_vaddr(buf, buflen);
_bus_dmamap_waitok(dmat, map, &mem, callback, callback_arg);
}
nsegs = -1;
error = _bus_dmamap_load_buffer(dmat, map, buf, buflen, kernel_pmap,
flags, NULL, &nsegs);
nsegs++;
CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
__func__, dmat, flags, error, nsegs + 1);
if (error == EINPROGRESS)
return (error);
segs = _bus_dmamap_complete(dmat, map, NULL, nsegs, error);
if (error)
(*callback)(callback_arg, segs, 0, error);
else
(*callback)(callback_arg, segs, nsegs, 0);
/*
* Return ENOMEM to the caller so that it can pass it up the stack.
* This error only happens when NOWAIT is set, so deferal is disabled.
*/
if (error == ENOMEM)
return (error);
return (0);
}
int
bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m0,
bus_dmamap_callback2_t *callback, void *callback_arg, int flags)
{
bus_dma_segment_t *segs;
int nsegs, error;
flags |= BUS_DMA_NOWAIT;
nsegs = -1;
error = _bus_dmamap_load_mbuf_sg(dmat, map, m0, NULL, &nsegs, flags);
++nsegs;
segs = _bus_dmamap_complete(dmat, map, NULL, nsegs, error);
if (error)
(*callback)(callback_arg, segs, 0, 0, error);
else
(*callback)(callback_arg, segs, nsegs, m0->m_pkthdr.len, error);
CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
__func__, dmat, flags, error, nsegs);
return (error);
}
int
bus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m0,
bus_dma_segment_t *segs, int *nsegs, int flags)
{
int error;
flags |= BUS_DMA_NOWAIT;
*nsegs = -1;
error = _bus_dmamap_load_mbuf_sg(dmat, map, m0, segs, nsegs, flags);
++*nsegs;
_bus_dmamap_complete(dmat, map, segs, *nsegs, error);
return (error);
}
int
bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map, struct uio *uio,
bus_dmamap_callback2_t *callback, void *callback_arg, int flags)
{
bus_dma_segment_t *segs;
int nsegs, error;
flags |= BUS_DMA_NOWAIT;
nsegs = -1;
error = _bus_dmamap_load_uio(dmat, map, uio, &nsegs, flags);
nsegs++;
segs = _bus_dmamap_complete(dmat, map, NULL, nsegs, error);
if (error)
(*callback)(callback_arg, segs, 0, 0, error);
else
(*callback)(callback_arg, segs, nsegs, uio->uio_resid, error);
CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
__func__, dmat, dmat, error, nsegs + 1);
return (error);
}
int
bus_dmamap_load_ccb(bus_dma_tag_t dmat, bus_dmamap_t map, union ccb *ccb,
bus_dmamap_callback_t *callback, void *callback_arg,
int flags)
{
bus_dma_segment_t *segs;
struct ccb_hdr *ccb_h;
struct memdesc mem;
int error;
int nsegs;
ccb_h = &ccb->ccb_h;
if ((ccb_h->flags & CAM_DIR_MASK) == CAM_DIR_NONE) {
callback(callback_arg, NULL, 0, 0);
return (0);
}
if ((flags & BUS_DMA_NOWAIT) == 0) {
mem = memdesc_ccb(ccb);
_bus_dmamap_waitok(dmat, map, &mem, callback, callback_arg);
}
nsegs = -1;
error = _bus_dmamap_load_ccb(dmat, map, ccb, &nsegs, flags);
nsegs++;
if (error == EINPROGRESS)
return (error);
segs = _bus_dmamap_complete(dmat, map, NULL, nsegs, error);
if (error)
(*callback)(callback_arg, segs, 0, error);
else
(*callback)(callback_arg, segs, nsegs, error);
/*
* Return ENOMEM to the caller so that it can pass it up the stack.
* This error only happens when NOWAIT is set, so deferal is disabled.
*/
if (error == ENOMEM)
return (error);
return (0);
}
int
bus_dmamap_load_mem(bus_dma_tag_t dmat, bus_dmamap_t map,
struct memdesc *mem, bus_dmamap_callback_t *callback,
void *callback_arg, int flags)
{
bus_dma_segment_t *segs;
int error;
int nsegs;
if ((flags & BUS_DMA_NOWAIT) == 0)
_bus_dmamap_waitok(dmat, map, mem, callback, callback_arg);
nsegs = -1;
error = 0;
switch (mem->md_type) {
case MEMDESC_VADDR:
error = _bus_dmamap_load_buffer(dmat, map, mem->u.md_vaddr,
mem->md_opaque, kernel_pmap, flags, NULL, &nsegs);
break;
case MEMDESC_PADDR:
error = _bus_dmamap_load_phys(dmat, map, mem->u.md_paddr,
mem->md_opaque, flags, NULL, &nsegs);
break;
case MEMDESC_VLIST:
error = _bus_dmamap_load_vlist(dmat, map, mem->u.md_list,
mem->md_opaque, kernel_pmap, &nsegs, flags);
break;
case MEMDESC_PLIST:
error = _bus_dmamap_load_plist(dmat, map, mem->u.md_list,
mem->md_opaque, &nsegs, flags);
break;
case MEMDESC_BIO:
error = _bus_dmamap_load_bio(dmat, map, mem->u.md_bio,
&nsegs, flags);
break;
case MEMDESC_UIO:
error = _bus_dmamap_load_uio(dmat, map, mem->u.md_uio,
&nsegs, flags);
break;
case MEMDESC_MBUF:
error = _bus_dmamap_load_mbuf_sg(dmat, map, mem->u.md_mbuf,
NULL, &nsegs, flags);
break;
case MEMDESC_CCB:
error = _bus_dmamap_load_ccb(dmat, map, mem->u.md_ccb, &nsegs,
flags);
break;
}
nsegs++;
CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
__func__, dmat, flags, error, nsegs + 1);
if (error == EINPROGRESS)
return (error);
segs = _bus_dmamap_complete(dmat, map, NULL, nsegs, error);
if (error)
(*callback)(callback_arg, segs, 0, error);
else
(*callback)(callback_arg, segs, nsegs, 0);
/*
* Return ENOMEM to the caller so that it can pass it up the stack.
* This error only happens when NOWAIT is set, so deferal is disabled.
*/
if (error == ENOMEM)
return (error);
return (0);
}