5.10-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit 62ed448cc53b654036f7d7f3c99f299d79ad14c3 ]
Transitioning between encode buffers is quite infrequent. It happens about 1 time in 400 calls to xdr_reserve_space(), measured on NFSD with a typical build/test workload.
Force the compiler to remove that code from xdr_reserve_space(), which is a hot path on both the server and the client. This change reduces the size of xdr_reserve_space() from 10 cache lines to 2 when compiled with -Os.
Signed-off-by: Chuck Lever chuck.lever@oracle.com Reviewed-by: J. Bruce Fields bfields@fieldses.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/sunrpc/xdr.h | 16 +++++++++++++++- net/sunrpc/xdr.c | 17 ++++++++++------- 2 files changed, 25 insertions(+), 8 deletions(-)
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index 927f1458bcab9..b8fb866e1fd32 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -242,7 +242,7 @@ extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes); extern int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes); -extern void xdr_commit_encode(struct xdr_stream *xdr); +extern void __xdr_commit_encode(struct xdr_stream *xdr); extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len); extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen); extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, @@ -305,6 +305,20 @@ xdr_reset_scratch_buffer(struct xdr_stream *xdr) xdr_set_scratch_buffer(xdr, NULL, 0); }
+/** + * xdr_commit_encode - Ensure all data is written to xdr->buf + * @xdr: pointer to xdr_stream + * + * Handle encoding across page boundaries by giving the caller a + * temporary location to write to, then later copying the data into + * place. __xdr_commit_encode() does that copying. + */ +static inline void xdr_commit_encode(struct xdr_stream *xdr) +{ + if (unlikely(xdr->scratch.iov_len)) + __xdr_commit_encode(xdr); +} + /** * xdr_stream_remaining - Return the number of bytes remaining in the stream * @xdr: pointer to struct xdr_stream diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 722586696fade..f66e2de7cd279 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -691,7 +691,7 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p, EXPORT_SYMBOL_GPL(xdr_init_encode);
/** - * xdr_commit_encode - Ensure all data is written to buffer + * __xdr_commit_encode - Ensure all data is written to buffer * @xdr: pointer to xdr_stream * * We handle encoding across page boundaries by giving the caller a @@ -703,22 +703,25 @@ EXPORT_SYMBOL_GPL(xdr_init_encode); * required at the end of encoding, or any other time when the xdr_buf * data might be read. */ -inline void xdr_commit_encode(struct xdr_stream *xdr) +void __xdr_commit_encode(struct xdr_stream *xdr) { int shift = xdr->scratch.iov_len; void *page;
- if (shift == 0) - return; page = page_address(*xdr->page_ptr); memcpy(xdr->scratch.iov_base, page, shift); memmove(page, page + shift, (void *)xdr->p - page); xdr_reset_scratch_buffer(xdr); } -EXPORT_SYMBOL_GPL(xdr_commit_encode); +EXPORT_SYMBOL_GPL(__xdr_commit_encode);
-static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, - size_t nbytes) +/* + * The buffer space to be reserved crosses the boundary between + * xdr->buf->head and xdr->buf->pages, or between two pages + * in xdr->buf->pages. + */ +static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, + size_t nbytes) { __be32 *p; int space_left;