* [PATCH RFC 1/6] SUNRPC: Capture value of xdr_buf::page_base
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 2/6] SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases Chuck Lever
` (5 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
This value will be non-zero more often, after subsequent patches are
applied. Knowing its value can be important diagnostic information.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
include/trace/events/sunrpc.h | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index d323f5a049c8..f13de06b7c1d 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -62,6 +62,7 @@ DECLARE_EVENT_CLASS(rpc_xdr_buf_class,
__field(size_t, head_len)
__field(const void *, tail_base)
__field(size_t, tail_len)
+ __field(unsigned int, page_base)
__field(unsigned int, page_len)
__field(unsigned int, msg_len)
),
@@ -74,14 +75,17 @@ DECLARE_EVENT_CLASS(rpc_xdr_buf_class,
__entry->head_len = xdr->head[0].iov_len;
__entry->tail_base = xdr->tail[0].iov_base;
__entry->tail_len = xdr->tail[0].iov_len;
+ __entry->page_base = xdr->page_base;
__entry->page_len = xdr->page_len;
__entry->msg_len = xdr->len;
),
- TP_printk("task:%u@%u head=[%p,%zu] page=%u tail=[%p,%zu] len=%u",
+ TP_printk("task:%u@%u head=[%p,%zu] page=%u(%u) tail=[%p,%zu] len=%u",
__entry->task_id, __entry->client_id,
- __entry->head_base, __entry->head_len, __entry->page_len,
- __entry->tail_base, __entry->tail_len, __entry->msg_len
+ __entry->head_base, __entry->head_len,
+ __entry->page_len, __entry->page_base,
+ __entry->tail_base, __entry->tail_len,
+ __entry->msg_len
)
);
@@ -1525,6 +1529,7 @@ DECLARE_EVENT_CLASS(svc_xdr_buf_class,
__field(size_t, head_len)
__field(const void *, tail_base)
__field(size_t, tail_len)
+ __field(unsigned int, page_base)
__field(unsigned int, page_len)
__field(unsigned int, msg_len)
),
@@ -1535,14 +1540,17 @@ DECLARE_EVENT_CLASS(svc_xdr_buf_class,
__entry->head_len = xdr->head[0].iov_len;
__entry->tail_base = xdr->tail[0].iov_base;
__entry->tail_len = xdr->tail[0].iov_len;
+ __entry->page_base = xdr->page_base;
__entry->page_len = xdr->page_len;
__entry->msg_len = xdr->len;
),
- TP_printk("xid=0x%08x head=[%p,%zu] page=%u tail=[%p,%zu] len=%u",
+ TP_printk("xid=0x%08x head=[%p,%zu] page=%u(%u) tail=[%p,%zu] len=%u",
__entry->xid,
- __entry->head_base, __entry->head_len, __entry->page_len,
- __entry->tail_base, __entry->tail_len, __entry->msg_len
+ __entry->head_base, __entry->head_len,
+ __entry->page_len, __entry->page_base,
+ __entry->tail_base, __entry->tail_len,
+ __entry->msg_len
)
);
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH RFC 2/6] SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 1/6] SUNRPC: Capture value of xdr_buf::page_base Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 3/6] NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment() Chuck Lever
` (4 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
xdr_stream_subsegment() was introduced in commit c1346a1216ab
("NFSD: Replace the internals of the READ_BUF() macro").
There are two call sites for xdr_stream_subsegment(). One is
nfsd4_decode_write(), and the other is nfsd4_decode_setxattr().
Currently neither of these call sites calls this API when
xdr_buf::page_base is a non-zero value.
However, I'm about to add a case where page_base will sometimes not
be zero when nfsd4_decode_write() invokes this API. Replace the
logic in xdr_stream_subsegment() that advances to the next data item
in the xdr_stream with something more generic in order to handle
this new use case.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
net/sunrpc/xdr.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index ca10ba2626f2..df194cc07035 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1633,7 +1633,7 @@ EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
* Sets up @subbuf to represent a portion of @xdr. The portion
* starts at the current offset in @xdr, and extends for a length
* of @nbytes. If this is successful, @xdr is advanced to the next
- * position following that portion.
+ * XDR data item following that portion.
*
* Return values:
* %true: @subbuf has been initialized, and @xdr has been advanced.
@@ -1642,29 +1642,31 @@ EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
unsigned int nbytes)
{
- unsigned int remaining, offset, len;
+ unsigned int start = xdr_stream_pos(xdr);
+ unsigned int remaining, len;
- if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
+ /* Extract @subbuf and bounds-check the fn arguments */
+ if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
return false;
- if (subbuf->head[0].iov_len)
- if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
- return false;
-
- remaining = subbuf->page_len;
- offset = subbuf->page_base;
- while (remaining) {
- len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
-
+ /* Advance @xdr by @nbytes */
+ for (remaining = nbytes; remaining;) {
if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return false;
- if (!__xdr_inline_decode(xdr, len))
- return false;
+ len = (char *)xdr->end - (char *)xdr->p;
+ if (remaining <= len) {
+ xdr->p = (__be32 *)((char *)xdr->p +
+ (remaining + xdr_pad_size(nbytes)));
+ break;
+ }
+
+ xdr->p = (__be32 *)((char *)xdr->p + len);
+ xdr->end = xdr->p;
remaining -= len;
- offset = 0;
}
+ xdr_stream_set_pos(xdr, start + nbytes);
return true;
}
EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH RFC 3/6] NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 1/6] SUNRPC: Capture value of xdr_buf::page_base Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 2/6] SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 4/6] SUNRPC: svc_fill_write_vector() must handle non-zero page_bases Chuck Lever
` (3 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
Refactor.
Now that the NFSv2 and NFSv3 XDR decoders have been converted to
use xdr_streams, the WRITE decoder functions can use
xdr_stream_subsegment() to extract the WRITE payload into its own
xdr_buf, just as the NFSv4 WRITE XDR decoder currently does.
That makes it possible to pass the first kvec, pages array + length,
page_base, and total payload length via a single function parameter.
The payload's page_base is not yet assigned or used, but will be in
subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfs3proc.c | 3 +--
fs/nfsd/nfs3xdr.c | 12 ++----------
fs/nfsd/nfs4proc.c | 3 +--
fs/nfsd/nfsproc.c | 3 +--
fs/nfsd/nfsxdr.c | 9 +--------
fs/nfsd/xdr.h | 2 +-
fs/nfsd/xdr3.h | 2 +-
include/linux/sunrpc/svc.h | 3 +--
net/sunrpc/svc.c | 11 ++++++-----
9 files changed, 15 insertions(+), 33 deletions(-)
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 17715a6c7a40..4418517f6f12 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -201,8 +201,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp)
fh_copy(&resp->fh, &argp->fh);
resp->committed = argp->stable;
- nvecs = svc_fill_write_vector(rqstp, rqstp->rq_arg.pages,
- &argp->first, cnt);
+ nvecs = svc_fill_write_vector(rqstp, &argp->payload);
if (!nvecs) {
resp->status = nfserr_io;
goto out;
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 0a5ebc52e6a9..91d4e2b8b854 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -621,9 +621,6 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd3_writeargs *args = rqstp->rq_argp;
u32 max_blocksize = svc_max_payload(rqstp);
- struct kvec *head = rqstp->rq_arg.head;
- struct kvec *tail = rqstp->rq_arg.tail;
- size_t remaining;
if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
return 0;
@@ -641,17 +638,12 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
/* request sanity */
if (args->count != args->len)
return 0;
- remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
- remaining -= xdr_stream_pos(xdr);
- if (remaining < xdr_align_size(args->len))
- return 0;
if (args->count > max_blocksize) {
args->count = max_blocksize;
args->len = max_blocksize;
}
-
- args->first.iov_base = xdr->p;
- args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
+ if (!xdr_stream_subsegment(xdr, &args->payload, args->count))
+ return 0;
return 1;
}
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 486c5dba4b65..55c9551fa74e 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1033,8 +1033,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
write->wr_how_written = write->wr_stable_how;
- nvecs = svc_fill_write_vector(rqstp, write->wr_payload.pages,
- write->wr_payload.head, write->wr_buflen);
+ nvecs = svc_fill_write_vector(rqstp, &write->wr_payload);
WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));
status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 90fcd6178823..eea5b59b6a6c 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -234,8 +234,7 @@ nfsd_proc_write(struct svc_rqst *rqstp)
SVCFH_fmt(&argp->fh),
argp->len, argp->offset);
- nvecs = svc_fill_write_vector(rqstp, rqstp->rq_arg.pages,
- &argp->first, cnt);
+ nvecs = svc_fill_write_vector(rqstp, &argp->payload);
if (!nvecs) {
resp->status = nfserr_io;
goto out;
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index a06c05fe3b42..26a42f87c240 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -325,10 +325,7 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_writeargs *args = rqstp->rq_argp;
- struct kvec *head = rqstp->rq_arg.head;
- struct kvec *tail = rqstp->rq_arg.tail;
u32 beginoffset, totalcount;
- size_t remaining;
if (!svcxdr_decode_fhandle(xdr, &args->fh))
return 0;
@@ -346,12 +343,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
return 0;
if (args->len > NFSSVC_MAXBLKSIZE_V2)
return 0;
- remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
- remaining -= xdr_stream_pos(xdr);
- if (remaining < xdr_align_size(args->len))
+ if (!xdr_stream_subsegment(xdr, &args->payload, args->len))
return 0;
- args->first.iov_base = xdr->p;
- args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
return 1;
}
diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h
index f45b4bc93f52..80fd6d7f3404 100644
--- a/fs/nfsd/xdr.h
+++ b/fs/nfsd/xdr.h
@@ -33,7 +33,7 @@ struct nfsd_writeargs {
svc_fh fh;
__u32 offset;
int len;
- struct kvec first;
+ struct xdr_buf payload;
};
struct nfsd_createargs {
diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index 933008382bbe..712c117300cb 100644
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -40,7 +40,7 @@ struct nfsd3_writeargs {
__u32 count;
int stable;
__u32 len;
- struct kvec first;
+ struct xdr_buf payload;
};
struct nfsd3_createargs {
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index f0f846fa396e..5a277acf2667 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -532,8 +532,7 @@ int svc_encode_result_payload(struct svc_rqst *rqstp,
unsigned int offset,
unsigned int length);
unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
- struct page **pages,
- struct kvec *first, size_t total);
+ struct xdr_buf *payload);
char *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
struct kvec *first, void *p,
size_t total);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index bfcbaf7b3822..34ced7f538ee 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1693,16 +1693,17 @@ EXPORT_SYMBOL_GPL(svc_encode_result_payload);
/**
* svc_fill_write_vector - Construct data argument for VFS write call
* @rqstp: svc_rqst to operate on
- * @pages: list of pages containing data payload
- * @first: buffer containing first section of write payload
- * @total: total number of bytes of write payload
+ * @payload: xdr_buf containing only the write data payload
*
* Fills in rqstp::rq_vec, and returns the number of elements.
*/
-unsigned int svc_fill_write_vector(struct svc_rqst *rqstp, struct page **pages,
- struct kvec *first, size_t total)
+unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
+ struct xdr_buf *payload)
{
+ struct page **pages = payload->pages;
+ struct kvec *first = payload->head;
struct kvec *vec = rqstp->rq_vec;
+ size_t total = payload->len;
unsigned int i;
/* Some types of transport can present the write payload
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH RFC 4/6] SUNRPC: svc_fill_write_vector() must handle non-zero page_bases
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
` (2 preceding siblings ...)
2021-08-31 19:05 ` [PATCH RFC 3/6] NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment() Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 5/6] NFSD: Add a transport hook for pulling argument payloads Chuck Lever
` (2 subsequent siblings)
6 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
svc_fill_write_vector() was introduced in commit 8154ef2776aa
("NFSD: Clean up legacy NFS WRITE argument XDR decoders").
I'm about to add a case where page_base will sometimes not be zero
when the NFS WRITE proc functions invoke this API. Refactor the
API and function internals to handle this case properly.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
net/sunrpc/svc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 34ced7f538ee..3d9f9da98aed 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1705,6 +1705,7 @@ unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
struct kvec *vec = rqstp->rq_vec;
size_t total = payload->len;
unsigned int i;
+ size_t offset;
/* Some types of transport can present the write payload
* entirely in rq_arg.pages. In this case, @first is empty.
@@ -1717,12 +1718,14 @@ unsigned int svc_fill_write_vector(struct svc_rqst *rqstp,
++i;
}
+ offset = payload->page_base;
while (total) {
- vec[i].iov_base = page_address(*pages);
- vec[i].iov_len = min_t(size_t, total, PAGE_SIZE);
+ vec[i].iov_base = page_address(*pages) + offset;
+ vec[i].iov_len = min_t(size_t, total, PAGE_SIZE - offset);
total -= vec[i].iov_len;
++i;
++pages;
+ offset = 0;
}
WARN_ON_ONCE(i > ARRAY_SIZE(rqstp->rq_vec));
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH RFC 5/6] NFSD: Add a transport hook for pulling argument payloads
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
` (3 preceding siblings ...)
2021-08-31 19:05 ` [PATCH RFC 4/6] SUNRPC: svc_fill_write_vector() must handle non-zero page_bases Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:05 ` [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload Chuck Lever
2021-08-31 20:42 ` [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders J. Bruce Fields
6 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
Refactor.
The new hook is a no-op at the moment, but it will soon be used to
pull RDMA Read chunks such that the payload is aligned to the pages
in the target file's page cache.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfs3xdr.c | 4 ++++
fs/nfsd/nfs4xdr.c | 6 ++++++
fs/nfsd/nfsxdr.c | 4 ++++
include/linux/sunrpc/svc.h | 3 +++
include/linux/sunrpc/svc_rdma.h | 2 ++
include/linux/sunrpc/svc_xprt.h | 3 +++
net/sunrpc/svc.c | 20 ++++++++++++++++++++
net/sunrpc/svcsock.c | 8 ++++++++
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 22 ++++++++++++++++++++++
net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 +
10 files changed, 73 insertions(+)
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 91d4e2b8b854..1bb61a7d125a 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -642,6 +642,8 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
args->count = max_blocksize;
args->len = max_blocksize;
}
+ if (svc_decode_argument_payload(rqstp, args->offset, args->len) < 0)
+ return 0;
if (!xdr_stream_subsegment(xdr, &args->payload, args->count))
return 0;
@@ -705,6 +707,8 @@ nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
remaining -= xdr_stream_pos(xdr);
if (remaining < xdr_align_size(args->tlen))
return 0;
+ if (svc_decode_argument_payload(rqstp, 0, args->tlen) < 0)
+ return 0;
args->first.iov_base = xdr->p;
args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7abeccb975b2..e919f409cb9c 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -813,6 +813,9 @@ nfsd4_decode_create(struct nfsd4_compoundargs *argp, struct nfsd4_create *create
p = xdr_inline_decode(argp->xdr, create->cr_datalen);
if (!p)
return nfserr_bad_xdr;
+ if (svc_decode_argument_payload(argp->rqstp, 0,
+ create->cr_datalen) < 0)
+ return nfserr_bad_xdr;
create->cr_data = svcxdr_dupstr(argp, p, create->cr_datalen);
if (!create->cr_data)
return nfserr_jukebox;
@@ -1410,6 +1413,9 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
return nfserr_bad_xdr;
if (xdr_stream_decode_u32(argp->xdr, &write->wr_buflen) < 0)
return nfserr_bad_xdr;
+ if (svc_decode_argument_payload(argp->rqstp, write->wr_offset,
+ write->wr_buflen) < 0)
+ return nfserr_bad_xdr;
if (!xdr_stream_subsegment(argp->xdr, &write->wr_payload, write->wr_buflen))
return nfserr_bad_xdr;
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 26a42f87c240..7c15f31f91da 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -343,6 +343,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
return 0;
if (args->len > NFSSVC_MAXBLKSIZE_V2)
return 0;
+ if (svc_decode_argument_payload(rqstp, args->offset, args->len) < 0)
+ return 0;
if (!xdr_stream_subsegment(xdr, &args->payload, args->len))
return 0;
@@ -397,6 +399,8 @@ nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
if (args->tlen == 0)
return 0;
+ if (svc_decode_argument_payload(rqstp, 0, args->tlen) < 0)
+ return 0;
args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
args->first.iov_base = xdr_inline_decode(xdr, args->tlen);
if (!args->first.iov_base)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 5a277acf2667..59d5016d9ec4 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -528,6 +528,9 @@ void svc_reserve(struct svc_rqst *rqstp, int space);
struct svc_pool * svc_pool_for_cpu(struct svc_serv *serv, int cpu);
char * svc_print_addr(struct svc_rqst *, char *, size_t);
const char * svc_proc_name(const struct svc_rqst *rqstp);
+int svc_decode_argument_payload(struct svc_rqst *rqstp,
+ unsigned int offset,
+ unsigned int length);
int svc_encode_result_payload(struct svc_rqst *rqstp,
unsigned int offset,
unsigned int length);
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 24aa159d29a7..f660244cc8ba 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -178,6 +178,8 @@ extern void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
extern void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma);
extern void svc_rdma_release_rqst(struct svc_rqst *rqstp);
extern int svc_rdma_recvfrom(struct svc_rqst *);
+extern int svc_rdma_argument_payload(struct svc_rqst *rqstp,
+ unsigned int offset, unsigned int length);
/* svc_rdma_rw.c */
extern void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma);
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 571f605bc91e..2d4c61f3307e 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -20,6 +20,9 @@ struct svc_xprt_ops {
struct svc_xprt *(*xpo_accept)(struct svc_xprt *);
int (*xpo_has_wspace)(struct svc_xprt *);
int (*xpo_recvfrom)(struct svc_rqst *);
+ int (*xpo_argument_payload)(struct svc_rqst *rqstp,
+ unsigned int offset,
+ unsigned int length);
int (*xpo_sendto)(struct svc_rqst *);
int (*xpo_result_payload)(struct svc_rqst *, unsigned int,
unsigned int);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 3d9f9da98aed..6eca2f420371 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1673,6 +1673,26 @@ const char *svc_proc_name(const struct svc_rqst *rqstp)
}
+/**
+ * svc_decode_argument_payload - set up pages containing an argument
+ * @rqstp: svc_rqst to operate on
+ * @offset: byte offset of payload in file's page cache
+ * @length: size of payload, in bytes
+ *
+ * This function can modify rqstp->rq_arg.page_base and the content
+ * of rqstp->rq_arg.pages, but no other fields of rq_arg are changed.
+ *
+ * Returns zero on success, or a negative errno if a permanent error
+ * occurred.
+ */
+int svc_decode_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length)
+{
+ return rqstp->rq_xprt->xpt_ops->xpo_argument_payload(rqstp, offset,
+ length);
+}
+EXPORT_SYMBOL_GPL(svc_decode_argument_payload);
+
/**
* svc_encode_result_payload - mark a range of bytes as a result payload
* @rqstp: svc_rqst to operate on
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 478f857cdaed..05eb63c182fd 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -181,6 +181,12 @@ static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
}
}
+static int svc_sock_argument_payload(struct svc_rqst *rqstp,
+ unsigned int offset, unsigned int length)
+{
+ return 0;
+}
+
static int svc_sock_result_payload(struct svc_rqst *rqstp, unsigned int offset,
unsigned int length)
{
@@ -637,6 +643,7 @@ static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
static const struct svc_xprt_ops svc_udp_ops = {
.xpo_create = svc_udp_create,
.xpo_recvfrom = svc_udp_recvfrom,
+ .xpo_argument_payload = svc_sock_argument_payload,
.xpo_sendto = svc_udp_sendto,
.xpo_result_payload = svc_sock_result_payload,
.xpo_release_rqst = svc_udp_release_rqst,
@@ -1208,6 +1215,7 @@ static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
static const struct svc_xprt_ops svc_tcp_ops = {
.xpo_create = svc_tcp_create,
.xpo_recvfrom = svc_tcp_recvfrom,
+ .xpo_argument_payload = svc_sock_argument_payload,
.xpo_sendto = svc_tcp_sendto,
.xpo_result_payload = svc_sock_result_payload,
.xpo_release_rqst = svc_tcp_release_rqst,
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index cf76a6ad127b..08a620b370ae 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -867,3 +867,25 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return 0;
}
+
+/**
+ * svc_rdma_argument_payload - special processing for an argument payload
+ * @rqstp: svc_rqst to operate on
+ * @offset: offset of payload in file's page cache
+ * @length: size of payload, in bytes
+ *
+ * Pull an RDMA Read payload chunk into rqstp->rq_arg.
+ *
+ * Return values:
+ * %0 if successful or nothing needed to be done
+ * %-EMSGSIZE on XDR buffer overflow
+ * %-EINVAL if client provided too many segments
+ * %-ENOMEM if rdma_rw context pool was exhausted
+ * %-ENOTCONN if posting failed (connection is lost)
+ * %-EIO if rdma_rw initialization failed (DMA mapping, etc)
+ */
+int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
+ unsigned int length)
+{
+ return 0;
+}
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 94b20fb47135..ee7cc112504c 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -79,6 +79,7 @@ static void svc_rdma_kill_temp_xprt(struct svc_xprt *);
static const struct svc_xprt_ops svc_rdma_ops = {
.xpo_create = svc_rdma_create,
.xpo_recvfrom = svc_rdma_recvfrom,
+ .xpo_argument_payload = svc_rdma_argument_payload,
.xpo_sendto = svc_rdma_sendto,
.xpo_result_payload = svc_rdma_result_payload,
.xpo_release_rqst = svc_rdma_release_rqst,
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
` (4 preceding siblings ...)
2021-08-31 19:05 ` [PATCH RFC 5/6] NFSD: Add a transport hook for pulling argument payloads Chuck Lever
@ 2021-08-31 19:05 ` Chuck Lever
2021-08-31 19:08 ` Chuck Lever III
2021-08-31 20:40 ` J. Bruce Fields
2021-08-31 20:42 ` [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders J. Bruce Fields
6 siblings, 2 replies; 13+ messages in thread
From: Chuck Lever @ 2021-08-31 19:05 UTC (permalink / raw)
To: bfields; +Cc: linux-nfs, linux-rdma
This enables the XDR decoder to figure out how the payload sink
buffer needs to be aligned before setting up the RDMA Reads.
Then re-alignment of large RDMA Read payloads can be avoided.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
include/linux/sunrpc/svc_rdma.h | 6 +
include/trace/events/rpcrdma.h | 26 ++++++
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++-
net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++++++++++---
4 files changed, 169 insertions(+), 19 deletions(-)
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index f660244cc8ba..8d80a759a909 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -192,6 +192,12 @@ extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *head);
+extern void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *head);
+extern int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma,
+ struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *ctxt,
+ unsigned int offset, unsigned int length);
/* svc_rdma_sendto.c */
extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
index 5954ce036173..30440cca321a 100644
--- a/include/trace/events/rpcrdma.h
+++ b/include/trace/events/rpcrdma.h
@@ -2136,6 +2136,32 @@ TRACE_EVENT(svcrdma_sq_post_err,
)
);
+TRACE_EVENT(svcrdma_arg_payload,
+ TP_PROTO(
+ const struct svc_rqst *rqstp,
+ unsigned int offset,
+ unsigned int length
+ ),
+
+ TP_ARGS(rqstp, offset, length),
+
+ TP_STRUCT__entry(
+ __field(u32, xid)
+ __field(u32, offset)
+ __field(u32, length)
+ ),
+
+ TP_fast_assign(
+ __entry->xid = __be32_to_cpu(rqstp->rq_xid);
+ __entry->offset = offset_in_page(offset);
+ __entry->length = length;
+ ),
+
+ TP_printk("xid=0x%08x offset=%u length=%u",
+ __entry->xid, __entry->offset, __entry->length
+ )
+);
+
#endif /* _TRACE_RPCRDMA_H */
#include <trace/define_trace.h>
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 08a620b370ae..cd9c0fb1a470 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -838,12 +838,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
- if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
- !pcl_is_empty(&ctxt->rc_call_pcl)) {
+ if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
+ ctxt->rc_read_pcl.cl_count > 1) {
ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
if (ret < 0)
goto out_readfail;
- }
+ } else if (ctxt->rc_read_pcl.cl_count == 1)
+ svc_rdma_prepare_read_chunk(rqstp, ctxt);
rqstp->rq_xprt_ctxt = ctxt;
rqstp->rq_prot = IPPROTO_MAX;
@@ -887,5 +888,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
unsigned int length)
{
- return 0;
+ struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
+ struct svc_xprt *xprt = rqstp->rq_xprt;
+ struct svcxprt_rdma *rdma =
+ container_of(xprt, struct svcxprt_rdma, sc_xprt);
+
+ if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
+ ctxt->rc_read_pcl.cl_count != 1)
+ return 0;
+ return svc_rdma_pull_read_chunk(rdma, rqstp, ctxt, offset, length);
}
diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 29b7d477891c..5f03dfd2fa03 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -707,19 +707,24 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
len = segment->rs_length;
sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
+
+ trace_printk("pageoff=%u len=%u sges=%u\n",
+ info->ri_pageoff, len, sge_no);
+
ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
if (!ctxt)
return -ENOMEM;
ctxt->rw_nents = sge_no;
+ head->rc_page_count += sge_no;
sg = ctxt->rw_sg_table.sgl;
for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
seg_len = min_t(unsigned int, len,
PAGE_SIZE - info->ri_pageoff);
- if (!info->ri_pageoff)
- head->rc_page_count++;
-
+ trace_printk(" page=%p seg_len=%u offset=%u\n",
+ rqstp->rq_pages[info->ri_pageno], seg_len,
+ info->ri_pageoff);
sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
seg_len, info->ri_pageoff);
sg = sg_next(sg);
@@ -804,15 +809,14 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
unsigned int page_no, numpages;
numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT;
+ head->rc_page_count += numpages;
+
for (page_no = 0; page_no < numpages; page_no++) {
unsigned int page_len;
page_len = min_t(unsigned int, remaining,
PAGE_SIZE - info->ri_pageoff);
- if (!info->ri_pageoff)
- head->rc_page_count++;
-
dst = page_address(rqstp->rq_pages[info->ri_pageno]);
memcpy(dst + info->ri_pageno, src + offset, page_len);
@@ -1092,15 +1096,8 @@ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info)
* @rqstp: set of pages to use as Read sink buffers
* @head: pages under I/O collect here
*
- * The RPC/RDMA protocol assumes that the upper layer's XDR decoders
- * pull each Read chunk as they decode an incoming RPC message.
- *
- * On Linux, however, the server needs to have a fully-constructed RPC
- * message in rqstp->rq_arg when there is a positive return code from
- * ->xpo_recvfrom. So the Read list is safety-checked immediately when
- * it is received, then here the whole Read list is pulled all at once.
- * The ingress RPC message is fully reconstructed once all associated
- * RDMA Reads have completed.
+ * Handle complex Read chunk cases fully before svc_rdma_recvfrom()
+ * returns.
*
* Return values:
* %1: all needed RDMA Reads were posted successfully,
@@ -1159,3 +1156,115 @@ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
svc_rdma_read_info_free(info);
return ret;
}
+
+/**
+ * svc_rdma_prepare_read_chunk - Prepare rq_arg for Read chunk
+ * @rqstp: set of pages to use as Read sink buffers
+ * @head: pages under I/O collect here
+ *
+ * The Read chunk will be pulled when the upper layer's XDR
+ * decoder calls svc_decode_argument_payload(). In the meantime,
+ * fake up rq_arg.page_len and .len to reflect the size of the
+ * yet-to-be-pulled payload.
+ */
+void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *head)
+{
+ struct svc_rdma_chunk *chunk = pcl_first_chunk(&head->rc_read_pcl);
+ unsigned int length = xdr_align_size(chunk->ch_length);
+ struct xdr_buf *buf = &rqstp->rq_arg;
+
+ buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
+ buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
+ buf->head[0].iov_len = chunk->ch_position;
+
+ buf->page_len = length;
+ buf->len += length;
+ buf->buflen += length;
+
+ /*
+ * rq_respages starts after the last arg page. Note that we
+ * don't know the offset yet, so add an extra page as slack.
+ */
+ length += PAGE_SIZE * 2 - 1;
+ rqstp->rq_respages = &rqstp->rq_pages[length >> PAGE_SHIFT];
+ rqstp->rq_next_page = rqstp->rq_respages + 1;
+}
+
+/**
+ * svc_rdma_pull_read_chunk - Pull one Read chunk from the client
+ * @rdma: controlling RDMA transport
+ * @rqstp: set of pages to use as Read sink buffers
+ * @head: pages under I/O collect here
+ * @offset: offset of payload in file's page cache
+ * @length: size of payload, in bytes
+ *
+ * Once the upper layer's XDR decoder has decoded the length of
+ * the payload and it's offset, we can be clever about setting up
+ * the RDMA Read sink buffer so that the VFS does not have to
+ * re-align the payload once it is received.
+ *
+ * Caveat: To keep things simple, this is an optimization that is
+ * used only when there is a single Read chunk in the Read
+ * list.
+ *
+ * Return values:
+ * %0: all needed RDMA Reads were posted successfully,
+ * %-EINVAL: client provided the wrong chunk size,
+ * %-ENOMEM: rdma_rw context pool was exhausted,
+ * %-ENOTCONN: posting failed (connection is lost),
+ * %-EIO: rdma_rw initialization failed (DMA mapping, etc).
+ */
+int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *head,
+ unsigned int offset, unsigned int length)
+{
+ struct svc_rdma_read_info *info;
+ struct svc_rdma_chunk_ctxt *cc;
+ struct svc_rdma_chunk *chunk;
+ int ret;
+
+ trace_svcrdma_arg_payload(rqstp, offset, length);
+
+ /* Sanity: the Requester must have provided enough
+ * bytes to fill the XDR opaque.
+ */
+ chunk = pcl_first_chunk(&head->rc_read_pcl);
+ if (length > chunk->ch_length)
+ return -EINVAL;
+
+ info = svc_rdma_read_info_alloc(rdma);
+ if (!info)
+ return -ENOMEM;
+ cc = &info->ri_cc;
+ info->ri_rqst = rqstp;
+ info->ri_readctxt = head;
+ info->ri_pageno = 0;
+ info->ri_pageoff = offset_in_page(offset);
+ info->ri_totalbytes = 0;
+
+ ret = svc_rdma_build_read_chunk(info, chunk);
+ if (ret < 0)
+ goto out_err;
+ rqstp->rq_arg.pages = &info->ri_rqst->rq_pages[0];
+ rqstp->rq_arg.page_base = offset_in_page(offset);
+ rqstp->rq_arg.buflen += offset_in_page(offset);
+
+ trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount);
+ init_completion(&cc->cc_done);
+ ret = svc_rdma_post_chunk_ctxt(cc);
+ if (ret < 0)
+ goto out_err;
+
+ ret = 0;
+ wait_for_completion(&cc->cc_done);
+ if (cc->cc_status != IB_WC_SUCCESS)
+ ret = -EIO;
+
+ /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */
+ head->rc_page_count = 0;
+
+out_err:
+ svc_rdma_read_info_free(info);
+ return ret;
+}
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload
2021-08-31 19:05 ` [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload Chuck Lever
@ 2021-08-31 19:08 ` Chuck Lever III
2021-08-31 20:40 ` J. Bruce Fields
1 sibling, 0 replies; 13+ messages in thread
From: Chuck Lever III @ 2021-08-31 19:08 UTC (permalink / raw)
To: Bruce Fields; +Cc: Linux NFS Mailing List, linux-rdma
> On Aug 31, 2021, at 3:05 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
>
> This enables the XDR decoder to figure out how the payload sink
> buffer needs to be aligned before setting up the RDMA Reads.
> Then re-alignment of large RDMA Read payloads can be avoided.
Should say "can be avoided" but isn't yet. All of these patches
are pre-requisites to that behavior.
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> include/linux/sunrpc/svc_rdma.h | 6 +
> include/trace/events/rpcrdma.h | 26 ++++++
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++-
> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++++++++++---
> 4 files changed, 169 insertions(+), 19 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index f660244cc8ba..8d80a759a909 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -192,6 +192,12 @@ extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
> extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> struct svc_rqst *rqstp,
> struct svc_rdma_recv_ctxt *head);
> +extern void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head);
> +extern int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma,
> + struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *ctxt,
> + unsigned int offset, unsigned int length);
>
> /* svc_rdma_sendto.c */
> extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
> diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
> index 5954ce036173..30440cca321a 100644
> --- a/include/trace/events/rpcrdma.h
> +++ b/include/trace/events/rpcrdma.h
> @@ -2136,6 +2136,32 @@ TRACE_EVENT(svcrdma_sq_post_err,
> )
> );
>
> +TRACE_EVENT(svcrdma_arg_payload,
> + TP_PROTO(
> + const struct svc_rqst *rqstp,
> + unsigned int offset,
> + unsigned int length
> + ),
> +
> + TP_ARGS(rqstp, offset, length),
> +
> + TP_STRUCT__entry(
> + __field(u32, xid)
> + __field(u32, offset)
> + __field(u32, length)
> + ),
> +
> + TP_fast_assign(
> + __entry->xid = __be32_to_cpu(rqstp->rq_xid);
> + __entry->offset = offset_in_page(offset);
> + __entry->length = length;
> + ),
> +
> + TP_printk("xid=0x%08x offset=%u length=%u",
> + __entry->xid, __entry->offset, __entry->length
> + )
> +);
> +
> #endif /* _TRACE_RPCRDMA_H */
>
> #include <trace/define_trace.h>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index 08a620b370ae..cd9c0fb1a470 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -838,12 +838,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
>
> svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
>
> - if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
> - !pcl_is_empty(&ctxt->rc_call_pcl)) {
> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> + ctxt->rc_read_pcl.cl_count > 1) {
> ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
> if (ret < 0)
> goto out_readfail;
> - }
> + } else if (ctxt->rc_read_pcl.cl_count == 1)
> + svc_rdma_prepare_read_chunk(rqstp, ctxt);
>
> rqstp->rq_xprt_ctxt = ctxt;
> rqstp->rq_prot = IPPROTO_MAX;
> @@ -887,5 +888,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
> int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
> unsigned int length)
> {
> - return 0;
> + struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
> + struct svc_xprt *xprt = rqstp->rq_xprt;
> + struct svcxprt_rdma *rdma =
> + container_of(xprt, struct svcxprt_rdma, sc_xprt);
> +
> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> + ctxt->rc_read_pcl.cl_count != 1)
> + return 0;
> + return svc_rdma_pull_read_chunk(rdma, rqstp, ctxt, offset, length);
> }
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> index 29b7d477891c..5f03dfd2fa03 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> @@ -707,19 +707,24 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
>
> len = segment->rs_length;
> sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
> +
> + trace_printk("pageoff=%u len=%u sges=%u\n",
> + info->ri_pageoff, len, sge_no);
> +
> ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
> if (!ctxt)
> return -ENOMEM;
> ctxt->rw_nents = sge_no;
> + head->rc_page_count += sge_no;
>
> sg = ctxt->rw_sg_table.sgl;
> for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
> seg_len = min_t(unsigned int, len,
> PAGE_SIZE - info->ri_pageoff);
>
> - if (!info->ri_pageoff)
> - head->rc_page_count++;
> -
> + trace_printk(" page=%p seg_len=%u offset=%u\n",
> + rqstp->rq_pages[info->ri_pageno], seg_len,
> + info->ri_pageoff);
> sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
> seg_len, info->ri_pageoff);
> sg = sg_next(sg);
> @@ -804,15 +809,14 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
> unsigned int page_no, numpages;
>
> numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT;
> + head->rc_page_count += numpages;
> +
> for (page_no = 0; page_no < numpages; page_no++) {
> unsigned int page_len;
>
> page_len = min_t(unsigned int, remaining,
> PAGE_SIZE - info->ri_pageoff);
>
> - if (!info->ri_pageoff)
> - head->rc_page_count++;
> -
> dst = page_address(rqstp->rq_pages[info->ri_pageno]);
> memcpy(dst + info->ri_pageno, src + offset, page_len);
>
> @@ -1092,15 +1096,8 @@ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info)
> * @rqstp: set of pages to use as Read sink buffers
> * @head: pages under I/O collect here
> *
> - * The RPC/RDMA protocol assumes that the upper layer's XDR decoders
> - * pull each Read chunk as they decode an incoming RPC message.
> - *
> - * On Linux, however, the server needs to have a fully-constructed RPC
> - * message in rqstp->rq_arg when there is a positive return code from
> - * ->xpo_recvfrom. So the Read list is safety-checked immediately when
> - * it is received, then here the whole Read list is pulled all at once.
> - * The ingress RPC message is fully reconstructed once all associated
> - * RDMA Reads have completed.
> + * Handle complex Read chunk cases fully before svc_rdma_recvfrom()
> + * returns.
> *
> * Return values:
> * %1: all needed RDMA Reads were posted successfully,
> @@ -1159,3 +1156,115 @@ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> svc_rdma_read_info_free(info);
> return ret;
> }
> +
> +/**
> + * svc_rdma_prepare_read_chunk - Prepare rq_arg for Read chunk
> + * @rqstp: set of pages to use as Read sink buffers
> + * @head: pages under I/O collect here
> + *
> + * The Read chunk will be pulled when the upper layer's XDR
> + * decoder calls svc_decode_argument_payload(). In the meantime,
> + * fake up rq_arg.page_len and .len to reflect the size of the
> + * yet-to-be-pulled payload.
> + */
> +void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head)
> +{
> + struct svc_rdma_chunk *chunk = pcl_first_chunk(&head->rc_read_pcl);
> + unsigned int length = xdr_align_size(chunk->ch_length);
> + struct xdr_buf *buf = &rqstp->rq_arg;
> +
> + buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
> + buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
> + buf->head[0].iov_len = chunk->ch_position;
> +
> + buf->page_len = length;
> + buf->len += length;
> + buf->buflen += length;
> +
> + /*
> + * rq_respages starts after the last arg page. Note that we
> + * don't know the offset yet, so add an extra page as slack.
> + */
> + length += PAGE_SIZE * 2 - 1;
> + rqstp->rq_respages = &rqstp->rq_pages[length >> PAGE_SHIFT];
> + rqstp->rq_next_page = rqstp->rq_respages + 1;
> +}
> +
> +/**
> + * svc_rdma_pull_read_chunk - Pull one Read chunk from the client
> + * @rdma: controlling RDMA transport
> + * @rqstp: set of pages to use as Read sink buffers
> + * @head: pages under I/O collect here
> + * @offset: offset of payload in file's page cache
> + * @length: size of payload, in bytes
> + *
> + * Once the upper layer's XDR decoder has decoded the length of
> + * the payload and it's offset, we can be clever about setting up
> + * the RDMA Read sink buffer so that the VFS does not have to
> + * re-align the payload once it is received.
> + *
> + * Caveat: To keep things simple, this is an optimization that is
> + * used only when there is a single Read chunk in the Read
> + * list.
> + *
> + * Return values:
> + * %0: all needed RDMA Reads were posted successfully,
> + * %-EINVAL: client provided the wrong chunk size,
> + * %-ENOMEM: rdma_rw context pool was exhausted,
> + * %-ENOTCONN: posting failed (connection is lost),
> + * %-EIO: rdma_rw initialization failed (DMA mapping, etc).
> + */
> +int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head,
> + unsigned int offset, unsigned int length)
> +{
> + struct svc_rdma_read_info *info;
> + struct svc_rdma_chunk_ctxt *cc;
> + struct svc_rdma_chunk *chunk;
> + int ret;
> +
> + trace_svcrdma_arg_payload(rqstp, offset, length);
> +
> + /* Sanity: the Requester must have provided enough
> + * bytes to fill the XDR opaque.
> + */
> + chunk = pcl_first_chunk(&head->rc_read_pcl);
> + if (length > chunk->ch_length)
> + return -EINVAL;
> +
> + info = svc_rdma_read_info_alloc(rdma);
> + if (!info)
> + return -ENOMEM;
> + cc = &info->ri_cc;
> + info->ri_rqst = rqstp;
> + info->ri_readctxt = head;
> + info->ri_pageno = 0;
> + info->ri_pageoff = offset_in_page(offset);
> + info->ri_totalbytes = 0;
> +
> + ret = svc_rdma_build_read_chunk(info, chunk);
> + if (ret < 0)
> + goto out_err;
> + rqstp->rq_arg.pages = &info->ri_rqst->rq_pages[0];
> + rqstp->rq_arg.page_base = offset_in_page(offset);
> + rqstp->rq_arg.buflen += offset_in_page(offset);
> +
> + trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount);
> + init_completion(&cc->cc_done);
> + ret = svc_rdma_post_chunk_ctxt(cc);
> + if (ret < 0)
> + goto out_err;
> +
> + ret = 0;
> + wait_for_completion(&cc->cc_done);
> + if (cc->cc_status != IB_WC_SUCCESS)
> + ret = -EIO;
> +
> + /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */
> + head->rc_page_count = 0;
> +
> +out_err:
> + svc_rdma_read_info_free(info);
> + return ret;
> +}
>
>
--
Chuck Lever
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload
2021-08-31 19:05 ` [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload Chuck Lever
2021-08-31 19:08 ` Chuck Lever III
@ 2021-08-31 20:40 ` J. Bruce Fields
2021-08-31 21:19 ` Chuck Lever III
1 sibling, 1 reply; 13+ messages in thread
From: J. Bruce Fields @ 2021-08-31 20:40 UTC (permalink / raw)
To: Chuck Lever; +Cc: linux-nfs, linux-rdma
How does this deal with compounds with multiple writes?
We don't need to handle those efficiently, but we do need to handle
them.
--b.
On Tue, Aug 31, 2021 at 03:05:46PM -0400, Chuck Lever wrote:
> This enables the XDR decoder to figure out how the payload sink
> buffer needs to be aligned before setting up the RDMA Reads.
> Then re-alignment of large RDMA Read payloads can be avoided.
>
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> include/linux/sunrpc/svc_rdma.h | 6 +
> include/trace/events/rpcrdma.h | 26 ++++++
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++-
> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++++++++++---
> 4 files changed, 169 insertions(+), 19 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index f660244cc8ba..8d80a759a909 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -192,6 +192,12 @@ extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
> extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> struct svc_rqst *rqstp,
> struct svc_rdma_recv_ctxt *head);
> +extern void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head);
> +extern int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma,
> + struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *ctxt,
> + unsigned int offset, unsigned int length);
>
> /* svc_rdma_sendto.c */
> extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
> diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
> index 5954ce036173..30440cca321a 100644
> --- a/include/trace/events/rpcrdma.h
> +++ b/include/trace/events/rpcrdma.h
> @@ -2136,6 +2136,32 @@ TRACE_EVENT(svcrdma_sq_post_err,
> )
> );
>
> +TRACE_EVENT(svcrdma_arg_payload,
> + TP_PROTO(
> + const struct svc_rqst *rqstp,
> + unsigned int offset,
> + unsigned int length
> + ),
> +
> + TP_ARGS(rqstp, offset, length),
> +
> + TP_STRUCT__entry(
> + __field(u32, xid)
> + __field(u32, offset)
> + __field(u32, length)
> + ),
> +
> + TP_fast_assign(
> + __entry->xid = __be32_to_cpu(rqstp->rq_xid);
> + __entry->offset = offset_in_page(offset);
> + __entry->length = length;
> + ),
> +
> + TP_printk("xid=0x%08x offset=%u length=%u",
> + __entry->xid, __entry->offset, __entry->length
> + )
> +);
> +
> #endif /* _TRACE_RPCRDMA_H */
>
> #include <trace/define_trace.h>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index 08a620b370ae..cd9c0fb1a470 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -838,12 +838,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
>
> svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
>
> - if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
> - !pcl_is_empty(&ctxt->rc_call_pcl)) {
> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> + ctxt->rc_read_pcl.cl_count > 1) {
> ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
> if (ret < 0)
> goto out_readfail;
> - }
> + } else if (ctxt->rc_read_pcl.cl_count == 1)
> + svc_rdma_prepare_read_chunk(rqstp, ctxt);
>
> rqstp->rq_xprt_ctxt = ctxt;
> rqstp->rq_prot = IPPROTO_MAX;
> @@ -887,5 +888,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
> int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
> unsigned int length)
> {
> - return 0;
> + struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
> + struct svc_xprt *xprt = rqstp->rq_xprt;
> + struct svcxprt_rdma *rdma =
> + container_of(xprt, struct svcxprt_rdma, sc_xprt);
> +
> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> + ctxt->rc_read_pcl.cl_count != 1)
> + return 0;
> + return svc_rdma_pull_read_chunk(rdma, rqstp, ctxt, offset, length);
> }
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> index 29b7d477891c..5f03dfd2fa03 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> @@ -707,19 +707,24 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
>
> len = segment->rs_length;
> sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
> +
> + trace_printk("pageoff=%u len=%u sges=%u\n",
> + info->ri_pageoff, len, sge_no);
> +
> ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
> if (!ctxt)
> return -ENOMEM;
> ctxt->rw_nents = sge_no;
> + head->rc_page_count += sge_no;
>
> sg = ctxt->rw_sg_table.sgl;
> for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
> seg_len = min_t(unsigned int, len,
> PAGE_SIZE - info->ri_pageoff);
>
> - if (!info->ri_pageoff)
> - head->rc_page_count++;
> -
> + trace_printk(" page=%p seg_len=%u offset=%u\n",
> + rqstp->rq_pages[info->ri_pageno], seg_len,
> + info->ri_pageoff);
> sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
> seg_len, info->ri_pageoff);
> sg = sg_next(sg);
> @@ -804,15 +809,14 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
> unsigned int page_no, numpages;
>
> numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT;
> + head->rc_page_count += numpages;
> +
> for (page_no = 0; page_no < numpages; page_no++) {
> unsigned int page_len;
>
> page_len = min_t(unsigned int, remaining,
> PAGE_SIZE - info->ri_pageoff);
>
> - if (!info->ri_pageoff)
> - head->rc_page_count++;
> -
> dst = page_address(rqstp->rq_pages[info->ri_pageno]);
> memcpy(dst + info->ri_pageno, src + offset, page_len);
>
> @@ -1092,15 +1096,8 @@ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info)
> * @rqstp: set of pages to use as Read sink buffers
> * @head: pages under I/O collect here
> *
> - * The RPC/RDMA protocol assumes that the upper layer's XDR decoders
> - * pull each Read chunk as they decode an incoming RPC message.
> - *
> - * On Linux, however, the server needs to have a fully-constructed RPC
> - * message in rqstp->rq_arg when there is a positive return code from
> - * ->xpo_recvfrom. So the Read list is safety-checked immediately when
> - * it is received, then here the whole Read list is pulled all at once.
> - * The ingress RPC message is fully reconstructed once all associated
> - * RDMA Reads have completed.
> + * Handle complex Read chunk cases fully before svc_rdma_recvfrom()
> + * returns.
> *
> * Return values:
> * %1: all needed RDMA Reads were posted successfully,
> @@ -1159,3 +1156,115 @@ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> svc_rdma_read_info_free(info);
> return ret;
> }
> +
> +/**
> + * svc_rdma_prepare_read_chunk - Prepare rq_arg for Read chunk
> + * @rqstp: set of pages to use as Read sink buffers
> + * @head: pages under I/O collect here
> + *
> + * The Read chunk will be pulled when the upper layer's XDR
> + * decoder calls svc_decode_argument_payload(). In the meantime,
> + * fake up rq_arg.page_len and .len to reflect the size of the
> + * yet-to-be-pulled payload.
> + */
> +void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head)
> +{
> + struct svc_rdma_chunk *chunk = pcl_first_chunk(&head->rc_read_pcl);
> + unsigned int length = xdr_align_size(chunk->ch_length);
> + struct xdr_buf *buf = &rqstp->rq_arg;
> +
> + buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
> + buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
> + buf->head[0].iov_len = chunk->ch_position;
> +
> + buf->page_len = length;
> + buf->len += length;
> + buf->buflen += length;
> +
> + /*
> + * rq_respages starts after the last arg page. Note that we
> + * don't know the offset yet, so add an extra page as slack.
> + */
> + length += PAGE_SIZE * 2 - 1;
> + rqstp->rq_respages = &rqstp->rq_pages[length >> PAGE_SHIFT];
> + rqstp->rq_next_page = rqstp->rq_respages + 1;
> +}
> +
> +/**
> + * svc_rdma_pull_read_chunk - Pull one Read chunk from the client
> + * @rdma: controlling RDMA transport
> + * @rqstp: set of pages to use as Read sink buffers
> + * @head: pages under I/O collect here
> + * @offset: offset of payload in file's page cache
> + * @length: size of payload, in bytes
> + *
> + * Once the upper layer's XDR decoder has decoded the length of
> + * the payload and it's offset, we can be clever about setting up
> + * the RDMA Read sink buffer so that the VFS does not have to
> + * re-align the payload once it is received.
> + *
> + * Caveat: To keep things simple, this is an optimization that is
> + * used only when there is a single Read chunk in the Read
> + * list.
> + *
> + * Return values:
> + * %0: all needed RDMA Reads were posted successfully,
> + * %-EINVAL: client provided the wrong chunk size,
> + * %-ENOMEM: rdma_rw context pool was exhausted,
> + * %-ENOTCONN: posting failed (connection is lost),
> + * %-EIO: rdma_rw initialization failed (DMA mapping, etc).
> + */
> +int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
> + struct svc_rdma_recv_ctxt *head,
> + unsigned int offset, unsigned int length)
> +{
> + struct svc_rdma_read_info *info;
> + struct svc_rdma_chunk_ctxt *cc;
> + struct svc_rdma_chunk *chunk;
> + int ret;
> +
> + trace_svcrdma_arg_payload(rqstp, offset, length);
> +
> + /* Sanity: the Requester must have provided enough
> + * bytes to fill the XDR opaque.
> + */
> + chunk = pcl_first_chunk(&head->rc_read_pcl);
> + if (length > chunk->ch_length)
> + return -EINVAL;
> +
> + info = svc_rdma_read_info_alloc(rdma);
> + if (!info)
> + return -ENOMEM;
> + cc = &info->ri_cc;
> + info->ri_rqst = rqstp;
> + info->ri_readctxt = head;
> + info->ri_pageno = 0;
> + info->ri_pageoff = offset_in_page(offset);
> + info->ri_totalbytes = 0;
> +
> + ret = svc_rdma_build_read_chunk(info, chunk);
> + if (ret < 0)
> + goto out_err;
> + rqstp->rq_arg.pages = &info->ri_rqst->rq_pages[0];
> + rqstp->rq_arg.page_base = offset_in_page(offset);
> + rqstp->rq_arg.buflen += offset_in_page(offset);
> +
> + trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount);
> + init_completion(&cc->cc_done);
> + ret = svc_rdma_post_chunk_ctxt(cc);
> + if (ret < 0)
> + goto out_err;
> +
> + ret = 0;
> + wait_for_completion(&cc->cc_done);
> + if (cc->cc_status != IB_WC_SUCCESS)
> + ret = -EIO;
> +
> + /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */
> + head->rc_page_count = 0;
> +
> +out_err:
> + svc_rdma_read_info_free(info);
> + return ret;
> +}
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload
2021-08-31 20:40 ` J. Bruce Fields
@ 2021-08-31 21:19 ` Chuck Lever III
2021-08-31 21:24 ` Bruce Fields
0 siblings, 1 reply; 13+ messages in thread
From: Chuck Lever III @ 2021-08-31 21:19 UTC (permalink / raw)
To: Bruce Fields; +Cc: Linux NFS Mailing List, linux-rdma
> On Aug 31, 2021, at 4:40 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
>
> How does this deal with compounds with multiple writes?
Explained in the cover letter.
> We don't need to handle those efficiently, but we do need to handle
> them.
>
> --b.
>
> On Tue, Aug 31, 2021 at 03:05:46PM -0400, Chuck Lever wrote:
>> This enables the XDR decoder to figure out how the payload sink
>> buffer needs to be aligned before setting up the RDMA Reads.
>> Then re-alignment of large RDMA Read payloads can be avoided.
>>
>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> ---
>> include/linux/sunrpc/svc_rdma.h | 6 +
>> include/trace/events/rpcrdma.h | 26 ++++++
>> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++-
>> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++++++++++---
>> 4 files changed, 169 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
>> index f660244cc8ba..8d80a759a909 100644
>> --- a/include/linux/sunrpc/svc_rdma.h
>> +++ b/include/linux/sunrpc/svc_rdma.h
>> @@ -192,6 +192,12 @@ extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
>> extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
>> struct svc_rqst *rqstp,
>> struct svc_rdma_recv_ctxt *head);
>> +extern void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
>> + struct svc_rdma_recv_ctxt *head);
>> +extern int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma,
>> + struct svc_rqst *rqstp,
>> + struct svc_rdma_recv_ctxt *ctxt,
>> + unsigned int offset, unsigned int length);
>>
>> /* svc_rdma_sendto.c */
>> extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
>> diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
>> index 5954ce036173..30440cca321a 100644
>> --- a/include/trace/events/rpcrdma.h
>> +++ b/include/trace/events/rpcrdma.h
>> @@ -2136,6 +2136,32 @@ TRACE_EVENT(svcrdma_sq_post_err,
>> )
>> );
>>
>> +TRACE_EVENT(svcrdma_arg_payload,
>> + TP_PROTO(
>> + const struct svc_rqst *rqstp,
>> + unsigned int offset,
>> + unsigned int length
>> + ),
>> +
>> + TP_ARGS(rqstp, offset, length),
>> +
>> + TP_STRUCT__entry(
>> + __field(u32, xid)
>> + __field(u32, offset)
>> + __field(u32, length)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->xid = __be32_to_cpu(rqstp->rq_xid);
>> + __entry->offset = offset_in_page(offset);
>> + __entry->length = length;
>> + ),
>> +
>> + TP_printk("xid=0x%08x offset=%u length=%u",
>> + __entry->xid, __entry->offset, __entry->length
>> + )
>> +);
>> +
>> #endif /* _TRACE_RPCRDMA_H */
>>
>> #include <trace/define_trace.h>
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>> index 08a620b370ae..cd9c0fb1a470 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>> @@ -838,12 +838,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
>>
>> svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
>>
>> - if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
>> - !pcl_is_empty(&ctxt->rc_call_pcl)) {
>> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
>> + ctxt->rc_read_pcl.cl_count > 1) {
>> ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
>> if (ret < 0)
>> goto out_readfail;
>> - }
>> + } else if (ctxt->rc_read_pcl.cl_count == 1)
>> + svc_rdma_prepare_read_chunk(rqstp, ctxt);
>>
>> rqstp->rq_xprt_ctxt = ctxt;
>> rqstp->rq_prot = IPPROTO_MAX;
>> @@ -887,5 +888,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
>> int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
>> unsigned int length)
>> {
>> - return 0;
>> + struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
>> + struct svc_xprt *xprt = rqstp->rq_xprt;
>> + struct svcxprt_rdma *rdma =
>> + container_of(xprt, struct svcxprt_rdma, sc_xprt);
>> +
>> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
>> + ctxt->rc_read_pcl.cl_count != 1)
>> + return 0;
>> + return svc_rdma_pull_read_chunk(rdma, rqstp, ctxt, offset, length);
>> }
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> index 29b7d477891c..5f03dfd2fa03 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> @@ -707,19 +707,24 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
>>
>> len = segment->rs_length;
>> sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
>> +
>> + trace_printk("pageoff=%u len=%u sges=%u\n",
>> + info->ri_pageoff, len, sge_no);
>> +
>> ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
>> if (!ctxt)
>> return -ENOMEM;
>> ctxt->rw_nents = sge_no;
>> + head->rc_page_count += sge_no;
>>
>> sg = ctxt->rw_sg_table.sgl;
>> for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
>> seg_len = min_t(unsigned int, len,
>> PAGE_SIZE - info->ri_pageoff);
>>
>> - if (!info->ri_pageoff)
>> - head->rc_page_count++;
>> -
>> + trace_printk(" page=%p seg_len=%u offset=%u\n",
>> + rqstp->rq_pages[info->ri_pageno], seg_len,
>> + info->ri_pageoff);
>> sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
>> seg_len, info->ri_pageoff);
>> sg = sg_next(sg);
>> @@ -804,15 +809,14 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
>> unsigned int page_no, numpages;
>>
>> numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT;
>> + head->rc_page_count += numpages;
>> +
>> for (page_no = 0; page_no < numpages; page_no++) {
>> unsigned int page_len;
>>
>> page_len = min_t(unsigned int, remaining,
>> PAGE_SIZE - info->ri_pageoff);
>>
>> - if (!info->ri_pageoff)
>> - head->rc_page_count++;
>> -
>> dst = page_address(rqstp->rq_pages[info->ri_pageno]);
>> memcpy(dst + info->ri_pageno, src + offset, page_len);
>>
>> @@ -1092,15 +1096,8 @@ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info)
>> * @rqstp: set of pages to use as Read sink buffers
>> * @head: pages under I/O collect here
>> *
>> - * The RPC/RDMA protocol assumes that the upper layer's XDR decoders
>> - * pull each Read chunk as they decode an incoming RPC message.
>> - *
>> - * On Linux, however, the server needs to have a fully-constructed RPC
>> - * message in rqstp->rq_arg when there is a positive return code from
>> - * ->xpo_recvfrom. So the Read list is safety-checked immediately when
>> - * it is received, then here the whole Read list is pulled all at once.
>> - * The ingress RPC message is fully reconstructed once all associated
>> - * RDMA Reads have completed.
>> + * Handle complex Read chunk cases fully before svc_rdma_recvfrom()
>> + * returns.
>> *
>> * Return values:
>> * %1: all needed RDMA Reads were posted successfully,
>> @@ -1159,3 +1156,115 @@ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
>> svc_rdma_read_info_free(info);
>> return ret;
>> }
>> +
>> +/**
>> + * svc_rdma_prepare_read_chunk - Prepare rq_arg for Read chunk
>> + * @rqstp: set of pages to use as Read sink buffers
>> + * @head: pages under I/O collect here
>> + *
>> + * The Read chunk will be pulled when the upper layer's XDR
>> + * decoder calls svc_decode_argument_payload(). In the meantime,
>> + * fake up rq_arg.page_len and .len to reflect the size of the
>> + * yet-to-be-pulled payload.
>> + */
>> +void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
>> + struct svc_rdma_recv_ctxt *head)
>> +{
>> + struct svc_rdma_chunk *chunk = pcl_first_chunk(&head->rc_read_pcl);
>> + unsigned int length = xdr_align_size(chunk->ch_length);
>> + struct xdr_buf *buf = &rqstp->rq_arg;
>> +
>> + buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
>> + buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
>> + buf->head[0].iov_len = chunk->ch_position;
>> +
>> + buf->page_len = length;
>> + buf->len += length;
>> + buf->buflen += length;
>> +
>> + /*
>> + * rq_respages starts after the last arg page. Note that we
>> + * don't know the offset yet, so add an extra page as slack.
>> + */
>> + length += PAGE_SIZE * 2 - 1;
>> + rqstp->rq_respages = &rqstp->rq_pages[length >> PAGE_SHIFT];
>> + rqstp->rq_next_page = rqstp->rq_respages + 1;
>> +}
>> +
>> +/**
>> + * svc_rdma_pull_read_chunk - Pull one Read chunk from the client
>> + * @rdma: controlling RDMA transport
>> + * @rqstp: set of pages to use as Read sink buffers
>> + * @head: pages under I/O collect here
>> + * @offset: offset of payload in file's page cache
>> + * @length: size of payload, in bytes
>> + *
>> + * Once the upper layer's XDR decoder has decoded the length of
>> + * the payload and it's offset, we can be clever about setting up
>> + * the RDMA Read sink buffer so that the VFS does not have to
>> + * re-align the payload once it is received.
>> + *
>> + * Caveat: To keep things simple, this is an optimization that is
>> + * used only when there is a single Read chunk in the Read
>> + * list.
>> + *
>> + * Return values:
>> + * %0: all needed RDMA Reads were posted successfully,
>> + * %-EINVAL: client provided the wrong chunk size,
>> + * %-ENOMEM: rdma_rw context pool was exhausted,
>> + * %-ENOTCONN: posting failed (connection is lost),
>> + * %-EIO: rdma_rw initialization failed (DMA mapping, etc).
>> + */
>> +int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
>> + struct svc_rdma_recv_ctxt *head,
>> + unsigned int offset, unsigned int length)
>> +{
>> + struct svc_rdma_read_info *info;
>> + struct svc_rdma_chunk_ctxt *cc;
>> + struct svc_rdma_chunk *chunk;
>> + int ret;
>> +
>> + trace_svcrdma_arg_payload(rqstp, offset, length);
>> +
>> + /* Sanity: the Requester must have provided enough
>> + * bytes to fill the XDR opaque.
>> + */
>> + chunk = pcl_first_chunk(&head->rc_read_pcl);
>> + if (length > chunk->ch_length)
>> + return -EINVAL;
>> +
>> + info = svc_rdma_read_info_alloc(rdma);
>> + if (!info)
>> + return -ENOMEM;
>> + cc = &info->ri_cc;
>> + info->ri_rqst = rqstp;
>> + info->ri_readctxt = head;
>> + info->ri_pageno = 0;
>> + info->ri_pageoff = offset_in_page(offset);
>> + info->ri_totalbytes = 0;
>> +
>> + ret = svc_rdma_build_read_chunk(info, chunk);
>> + if (ret < 0)
>> + goto out_err;
>> + rqstp->rq_arg.pages = &info->ri_rqst->rq_pages[0];
>> + rqstp->rq_arg.page_base = offset_in_page(offset);
>> + rqstp->rq_arg.buflen += offset_in_page(offset);
>> +
>> + trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount);
>> + init_completion(&cc->cc_done);
>> + ret = svc_rdma_post_chunk_ctxt(cc);
>> + if (ret < 0)
>> + goto out_err;
>> +
>> + ret = 0;
>> + wait_for_completion(&cc->cc_done);
>> + if (cc->cc_status != IB_WC_SUCCESS)
>> + ret = -EIO;
>> +
>> + /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */
>> + head->rc_page_count = 0;
>> +
>> +out_err:
>> + svc_rdma_read_info_free(info);
>> + return ret;
>> +}
>>
--
Chuck Lever
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload
2021-08-31 21:19 ` Chuck Lever III
@ 2021-08-31 21:24 ` Bruce Fields
0 siblings, 0 replies; 13+ messages in thread
From: Bruce Fields @ 2021-08-31 21:24 UTC (permalink / raw)
To: Chuck Lever III; +Cc: Linux NFS Mailing List, linux-rdma
On Tue, Aug 31, 2021 at 09:19:23PM +0000, Chuck Lever III wrote:
>
> > On Aug 31, 2021, at 4:40 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> >
> > How does this deal with compounds with multiple writes?
>
> Explained in the cover letter.
Whoops, I see now, thanks.--b.
>
>
> > We don't need to handle those efficiently, but we do need to handle
> > them.
> >
> > --b.
> >
> > On Tue, Aug 31, 2021 at 03:05:46PM -0400, Chuck Lever wrote:
> >> This enables the XDR decoder to figure out how the payload sink
> >> buffer needs to be aligned before setting up the RDMA Reads.
> >> Then re-alignment of large RDMA Read payloads can be avoided.
> >>
> >> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> >> ---
> >> include/linux/sunrpc/svc_rdma.h | 6 +
> >> include/trace/events/rpcrdma.h | 26 ++++++
> >> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 17 +++-
> >> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++++++++++---
> >> 4 files changed, 169 insertions(+), 19 deletions(-)
> >>
> >> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> >> index f660244cc8ba..8d80a759a909 100644
> >> --- a/include/linux/sunrpc/svc_rdma.h
> >> +++ b/include/linux/sunrpc/svc_rdma.h
> >> @@ -192,6 +192,12 @@ extern int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
> >> extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> >> struct svc_rqst *rqstp,
> >> struct svc_rdma_recv_ctxt *head);
> >> +extern void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> >> + struct svc_rdma_recv_ctxt *head);
> >> +extern int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma,
> >> + struct svc_rqst *rqstp,
> >> + struct svc_rdma_recv_ctxt *ctxt,
> >> + unsigned int offset, unsigned int length);
> >>
> >> /* svc_rdma_sendto.c */
> >> extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
> >> diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
> >> index 5954ce036173..30440cca321a 100644
> >> --- a/include/trace/events/rpcrdma.h
> >> +++ b/include/trace/events/rpcrdma.h
> >> @@ -2136,6 +2136,32 @@ TRACE_EVENT(svcrdma_sq_post_err,
> >> )
> >> );
> >>
> >> +TRACE_EVENT(svcrdma_arg_payload,
> >> + TP_PROTO(
> >> + const struct svc_rqst *rqstp,
> >> + unsigned int offset,
> >> + unsigned int length
> >> + ),
> >> +
> >> + TP_ARGS(rqstp, offset, length),
> >> +
> >> + TP_STRUCT__entry(
> >> + __field(u32, xid)
> >> + __field(u32, offset)
> >> + __field(u32, length)
> >> + ),
> >> +
> >> + TP_fast_assign(
> >> + __entry->xid = __be32_to_cpu(rqstp->rq_xid);
> >> + __entry->offset = offset_in_page(offset);
> >> + __entry->length = length;
> >> + ),
> >> +
> >> + TP_printk("xid=0x%08x offset=%u length=%u",
> >> + __entry->xid, __entry->offset, __entry->length
> >> + )
> >> +);
> >> +
> >> #endif /* _TRACE_RPCRDMA_H */
> >>
> >> #include <trace/define_trace.h>
> >> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >> index 08a620b370ae..cd9c0fb1a470 100644
> >> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >> @@ -838,12 +838,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
> >>
> >> svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
> >>
> >> - if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
> >> - !pcl_is_empty(&ctxt->rc_call_pcl)) {
> >> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> >> + ctxt->rc_read_pcl.cl_count > 1) {
> >> ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
> >> if (ret < 0)
> >> goto out_readfail;
> >> - }
> >> + } else if (ctxt->rc_read_pcl.cl_count == 1)
> >> + svc_rdma_prepare_read_chunk(rqstp, ctxt);
> >>
> >> rqstp->rq_xprt_ctxt = ctxt;
> >> rqstp->rq_prot = IPPROTO_MAX;
> >> @@ -887,5 +888,13 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
> >> int svc_rdma_argument_payload(struct svc_rqst *rqstp, unsigned int offset,
> >> unsigned int length)
> >> {
> >> - return 0;
> >> + struct svc_rdma_recv_ctxt *ctxt = rqstp->rq_xprt_ctxt;
> >> + struct svc_xprt *xprt = rqstp->rq_xprt;
> >> + struct svcxprt_rdma *rdma =
> >> + container_of(xprt, struct svcxprt_rdma, sc_xprt);
> >> +
> >> + if (!pcl_is_empty(&ctxt->rc_call_pcl) ||
> >> + ctxt->rc_read_pcl.cl_count != 1)
> >> + return 0;
> >> + return svc_rdma_pull_read_chunk(rdma, rqstp, ctxt, offset, length);
> >> }
> >> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> >> index 29b7d477891c..5f03dfd2fa03 100644
> >> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
> >> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
> >> @@ -707,19 +707,24 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
> >>
> >> len = segment->rs_length;
> >> sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
> >> +
> >> + trace_printk("pageoff=%u len=%u sges=%u\n",
> >> + info->ri_pageoff, len, sge_no);
> >> +
> >> ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
> >> if (!ctxt)
> >> return -ENOMEM;
> >> ctxt->rw_nents = sge_no;
> >> + head->rc_page_count += sge_no;
> >>
> >> sg = ctxt->rw_sg_table.sgl;
> >> for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
> >> seg_len = min_t(unsigned int, len,
> >> PAGE_SIZE - info->ri_pageoff);
> >>
> >> - if (!info->ri_pageoff)
> >> - head->rc_page_count++;
> >> -
> >> + trace_printk(" page=%p seg_len=%u offset=%u\n",
> >> + rqstp->rq_pages[info->ri_pageno], seg_len,
> >> + info->ri_pageoff);
> >> sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
> >> seg_len, info->ri_pageoff);
> >> sg = sg_next(sg);
> >> @@ -804,15 +809,14 @@ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info,
> >> unsigned int page_no, numpages;
> >>
> >> numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT;
> >> + head->rc_page_count += numpages;
> >> +
> >> for (page_no = 0; page_no < numpages; page_no++) {
> >> unsigned int page_len;
> >>
> >> page_len = min_t(unsigned int, remaining,
> >> PAGE_SIZE - info->ri_pageoff);
> >>
> >> - if (!info->ri_pageoff)
> >> - head->rc_page_count++;
> >> -
> >> dst = page_address(rqstp->rq_pages[info->ri_pageno]);
> >> memcpy(dst + info->ri_pageno, src + offset, page_len);
> >>
> >> @@ -1092,15 +1096,8 @@ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info)
> >> * @rqstp: set of pages to use as Read sink buffers
> >> * @head: pages under I/O collect here
> >> *
> >> - * The RPC/RDMA protocol assumes that the upper layer's XDR decoders
> >> - * pull each Read chunk as they decode an incoming RPC message.
> >> - *
> >> - * On Linux, however, the server needs to have a fully-constructed RPC
> >> - * message in rqstp->rq_arg when there is a positive return code from
> >> - * ->xpo_recvfrom. So the Read list is safety-checked immediately when
> >> - * it is received, then here the whole Read list is pulled all at once.
> >> - * The ingress RPC message is fully reconstructed once all associated
> >> - * RDMA Reads have completed.
> >> + * Handle complex Read chunk cases fully before svc_rdma_recvfrom()
> >> + * returns.
> >> *
> >> * Return values:
> >> * %1: all needed RDMA Reads were posted successfully,
> >> @@ -1159,3 +1156,115 @@ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
> >> svc_rdma_read_info_free(info);
> >> return ret;
> >> }
> >> +
> >> +/**
> >> + * svc_rdma_prepare_read_chunk - Prepare rq_arg for Read chunk
> >> + * @rqstp: set of pages to use as Read sink buffers
> >> + * @head: pages under I/O collect here
> >> + *
> >> + * The Read chunk will be pulled when the upper layer's XDR
> >> + * decoder calls svc_decode_argument_payload(). In the meantime,
> >> + * fake up rq_arg.page_len and .len to reflect the size of the
> >> + * yet-to-be-pulled payload.
> >> + */
> >> +void svc_rdma_prepare_read_chunk(struct svc_rqst *rqstp,
> >> + struct svc_rdma_recv_ctxt *head)
> >> +{
> >> + struct svc_rdma_chunk *chunk = pcl_first_chunk(&head->rc_read_pcl);
> >> + unsigned int length = xdr_align_size(chunk->ch_length);
> >> + struct xdr_buf *buf = &rqstp->rq_arg;
> >> +
> >> + buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
> >> + buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
> >> + buf->head[0].iov_len = chunk->ch_position;
> >> +
> >> + buf->page_len = length;
> >> + buf->len += length;
> >> + buf->buflen += length;
> >> +
> >> + /*
> >> + * rq_respages starts after the last arg page. Note that we
> >> + * don't know the offset yet, so add an extra page as slack.
> >> + */
> >> + length += PAGE_SIZE * 2 - 1;
> >> + rqstp->rq_respages = &rqstp->rq_pages[length >> PAGE_SHIFT];
> >> + rqstp->rq_next_page = rqstp->rq_respages + 1;
> >> +}
> >> +
> >> +/**
> >> + * svc_rdma_pull_read_chunk - Pull one Read chunk from the client
> >> + * @rdma: controlling RDMA transport
> >> + * @rqstp: set of pages to use as Read sink buffers
> >> + * @head: pages under I/O collect here
> >> + * @offset: offset of payload in file's page cache
> >> + * @length: size of payload, in bytes
> >> + *
> >> + * Once the upper layer's XDR decoder has decoded the length of
> >> + * the payload and it's offset, we can be clever about setting up
> >> + * the RDMA Read sink buffer so that the VFS does not have to
> >> + * re-align the payload once it is received.
> >> + *
> >> + * Caveat: To keep things simple, this is an optimization that is
> >> + * used only when there is a single Read chunk in the Read
> >> + * list.
> >> + *
> >> + * Return values:
> >> + * %0: all needed RDMA Reads were posted successfully,
> >> + * %-EINVAL: client provided the wrong chunk size,
> >> + * %-ENOMEM: rdma_rw context pool was exhausted,
> >> + * %-ENOTCONN: posting failed (connection is lost),
> >> + * %-EIO: rdma_rw initialization failed (DMA mapping, etc).
> >> + */
> >> +int svc_rdma_pull_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
> >> + struct svc_rdma_recv_ctxt *head,
> >> + unsigned int offset, unsigned int length)
> >> +{
> >> + struct svc_rdma_read_info *info;
> >> + struct svc_rdma_chunk_ctxt *cc;
> >> + struct svc_rdma_chunk *chunk;
> >> + int ret;
> >> +
> >> + trace_svcrdma_arg_payload(rqstp, offset, length);
> >> +
> >> + /* Sanity: the Requester must have provided enough
> >> + * bytes to fill the XDR opaque.
> >> + */
> >> + chunk = pcl_first_chunk(&head->rc_read_pcl);
> >> + if (length > chunk->ch_length)
> >> + return -EINVAL;
> >> +
> >> + info = svc_rdma_read_info_alloc(rdma);
> >> + if (!info)
> >> + return -ENOMEM;
> >> + cc = &info->ri_cc;
> >> + info->ri_rqst = rqstp;
> >> + info->ri_readctxt = head;
> >> + info->ri_pageno = 0;
> >> + info->ri_pageoff = offset_in_page(offset);
> >> + info->ri_totalbytes = 0;
> >> +
> >> + ret = svc_rdma_build_read_chunk(info, chunk);
> >> + if (ret < 0)
> >> + goto out_err;
> >> + rqstp->rq_arg.pages = &info->ri_rqst->rq_pages[0];
> >> + rqstp->rq_arg.page_base = offset_in_page(offset);
> >> + rqstp->rq_arg.buflen += offset_in_page(offset);
> >> +
> >> + trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount);
> >> + init_completion(&cc->cc_done);
> >> + ret = svc_rdma_post_chunk_ctxt(cc);
> >> + if (ret < 0)
> >> + goto out_err;
> >> +
> >> + ret = 0;
> >> + wait_for_completion(&cc->cc_done);
> >> + if (cc->cc_status != IB_WC_SUCCESS)
> >> + ret = -EIO;
> >> +
> >> + /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */
> >> + head->rc_page_count = 0;
> >> +
> >> +out_err:
> >> + svc_rdma_read_info_free(info);
> >> + return ret;
> >> +}
> >>
>
> --
> Chuck Lever
>
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders
2021-08-31 19:05 [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders Chuck Lever
` (5 preceding siblings ...)
2021-08-31 19:05 ` [PATCH RFC 6/6] svcrdma: Pull Read chunks in ->xpo_argument_payload Chuck Lever
@ 2021-08-31 20:42 ` J. Bruce Fields
2021-08-31 21:23 ` Chuck Lever III
6 siblings, 1 reply; 13+ messages in thread
From: J. Bruce Fields @ 2021-08-31 20:42 UTC (permalink / raw)
To: Chuck Lever; +Cc: linux-nfs, linux-rdma
On Tue, Aug 31, 2021 at 03:05:09PM -0400, Chuck Lever wrote:
> Hi Bruce-
>
> Here is part of what we discussed recently about trying to align
> pages in NFS WRITE requests so that splice can be used. This
> series updates server-side RPC and svcrdma to ensure that an
> aligned xdr_buf::pages array is presented to NFSD, which is then
> converted into an aligned rq_vec for the VFS layer.
Seems sensible to me.
Do you have a git tree? It didn't apply cleanly to 5.14 when I tried,
but I didn't stop to figure out why.
> The next step would be to look at how to make the best use of the
> aligned rq_vec.
Have you done any performance comparison just with this?
Doesn't seem like it should make a significant difference, but it might
be interesting to check anyway.
--b.
> My naive thought is that where there is a PAGE_SIZE
> entry in rq_vec and there is no page in the file's page cache at
> that offset, the transport-provided page can be flipped into place.
> Might work for replacing whole pages as well, but baby steps first.
>
> This series has been exercised a bit with both TCP and RDMA, but no
> guarantees that it is completely bug-free. NFSv4 compounds with
> multiple WRITE payloads on RDMA are treated like TCP: the RPC
> message is contained in an unstructured stream of unaligned pages.
>
> Comments encouraged.
>
> ---
>
> Chuck Lever (6):
> SUNRPC: Capture value of xdr_buf::page_base
> SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
> NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
> SUNRPC: svc_fill_write_vector() must handle non-zero page_bases
> NFSD: Add a transport hook for pulling argument payloads
> svcrdma: Pull Read chunks in ->xpo_argument_payload
>
>
> fs/nfsd/nfs3proc.c | 3 +-
> fs/nfsd/nfs3xdr.c | 16 +--
> fs/nfsd/nfs4proc.c | 3 +-
> fs/nfsd/nfs4xdr.c | 6 +
> fs/nfsd/nfsproc.c | 3 +-
> fs/nfsd/nfsxdr.c | 13 +--
> fs/nfsd/xdr.h | 2 +-
> fs/nfsd/xdr3.h | 2 +-
> include/linux/sunrpc/svc.h | 6 +-
> include/linux/sunrpc/svc_rdma.h | 8 ++
> include/linux/sunrpc/svc_xprt.h | 3 +
> include/trace/events/rpcrdma.h | 26 +++++
> include/trace/events/sunrpc.h | 20 +++-
> net/sunrpc/svc.c | 38 +++++--
> net/sunrpc/svcsock.c | 8 ++
> net/sunrpc/xdr.c | 32 +++---
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 37 +++++-
> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++---
> net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 +
> 19 files changed, 292 insertions(+), 74 deletions(-)
>
> --
> Chuck Lever
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders
2021-08-31 20:42 ` [PATCH RFC 0/6] NFSD: Pull Read chunks in XDR decoders J. Bruce Fields
@ 2021-08-31 21:23 ` Chuck Lever III
0 siblings, 0 replies; 13+ messages in thread
From: Chuck Lever III @ 2021-08-31 21:23 UTC (permalink / raw)
To: Bruce Fields; +Cc: Linux NFS Mailing List, linux-rdma
> On Aug 31, 2021, at 4:42 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
>
> On Tue, Aug 31, 2021 at 03:05:09PM -0400, Chuck Lever wrote:
>> Hi Bruce-
>>
>> Here is part of what we discussed recently about trying to align
>> pages in NFS WRITE requests so that splice can be used. This
>> series updates server-side RPC and svcrdma to ensure that an
>> aligned xdr_buf::pages array is presented to NFSD, which is then
>> converted into an aligned rq_vec for the VFS layer.
>
> Seems sensible to me.
>
> Do you have a git tree?
I don't yet, but can set up a topic branch somewhere where we're
a little further along.
> It didn't apply cleanly to 5.14 when I tried,
> but I didn't stop to figure out why.
It might apply to 5.15-pre now that nfsd-5.15 has been merged.
>> The next step would be to look at how to make the best use of the
>> aligned rq_vec.
>
> Have you done any performance comparison just with this?
Not yet. I just got it behaving correctly with the usual tests.
Baby steps, sir.
> Doesn't seem like it should make a significant difference, but it might
> be interesting to check anyway.
I expect it to add a small amount of latency to NFS WRITEs, since
RDMA Reads are done just a little later than before.
> --b.
>
>> My naive thought is that where there is a PAGE_SIZE
>> entry in rq_vec and there is no page in the file's page cache at
>> that offset, the transport-provided page can be flipped into place.
>> Might work for replacing whole pages as well, but baby steps first.
>>
>> This series has been exercised a bit with both TCP and RDMA, but no
>> guarantees that it is completely bug-free. NFSv4 compounds with
>> multiple WRITE payloads on RDMA are treated like TCP: the RPC
>> message is contained in an unstructured stream of unaligned pages.
>>
>> Comments encouraged.
>>
>> ---
>>
>> Chuck Lever (6):
>> SUNRPC: Capture value of xdr_buf::page_base
>> SUNRPC: xdr_stream_subsegment() must handle non-zero page_bases
>> NFSD: Have legacy NFSD WRITE decoders use xdr_stream_subsegment()
>> SUNRPC: svc_fill_write_vector() must handle non-zero page_bases
>> NFSD: Add a transport hook for pulling argument payloads
>> svcrdma: Pull Read chunks in ->xpo_argument_payload
>>
>>
>> fs/nfsd/nfs3proc.c | 3 +-
>> fs/nfsd/nfs3xdr.c | 16 +--
>> fs/nfsd/nfs4proc.c | 3 +-
>> fs/nfsd/nfs4xdr.c | 6 +
>> fs/nfsd/nfsproc.c | 3 +-
>> fs/nfsd/nfsxdr.c | 13 +--
>> fs/nfsd/xdr.h | 2 +-
>> fs/nfsd/xdr3.h | 2 +-
>> include/linux/sunrpc/svc.h | 6 +-
>> include/linux/sunrpc/svc_rdma.h | 8 ++
>> include/linux/sunrpc/svc_xprt.h | 3 +
>> include/trace/events/rpcrdma.h | 26 +++++
>> include/trace/events/sunrpc.h | 20 +++-
>> net/sunrpc/svc.c | 38 +++++--
>> net/sunrpc/svcsock.c | 8 ++
>> net/sunrpc/xdr.c | 32 +++---
>> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 37 +++++-
>> net/sunrpc/xprtrdma/svc_rdma_rw.c | 139 ++++++++++++++++++++---
>> net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 +
>> 19 files changed, 292 insertions(+), 74 deletions(-)
>>
>> --
>> Chuck Lever
--
Chuck Lever
^ permalink raw reply [flat|nested] 13+ messages in thread