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author | Chuck Lever <chuck.lever@oracle.com> | 2021-04-29 23:01:58 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-30 11:20:43 -0700 |
commit | ab8362645fba90fa44ec1991ad05544e307dd02f (patch) | |
tree | a8dabb99d92429d2d3d33b2afeb06251a766ac3d /net | |
parent | 3b822017b636bf4261a644c16b01eb3900f2a9a0 (diff) | |
download | linux-ab8362645fba90fa44ec1991ad05544e307dd02f.tar.bz2 |
SUNRPC: set rq_page_end differently
Patch series "SUNRPC consumer for the bulk page allocator"
This patch set and the measurements below are based on yesterday's
bulk allocator series:
git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux.git mm-bulk-rebase-v5r9
The patches change SUNRPC to invoke the array-based bulk allocator
instead of alloc_page().
The micro-benchmark results are promising. I ran a mixture of 256KB
reads and writes over NFSv3. The server's kernel is built with KASAN
enabled, so the comparison is exaggerated but I believe it is still
valid.
I instrumented svc_recv() to measure the latency of each call to
svc_alloc_arg() and report it via a trace point. The following results
are averages across the trace events.
Single page: 25.007 us per call over 532,571 calls
Bulk list: 6.258 us per call over 517,034 calls
Bulk array: 4.590 us per call over 517,442 calls
This patch (of 2)
Refactor:
I'm about to use the loop variable @i for something else.
As far as the "i++" is concerned, that is a post-increment. The
value of @i is not used subsequently, so the increment operator
is unnecessary and can be removed.
Also note that nfsd_read_actor() was renamed nfsd_splice_actor()
by commit cf8208d0eabd ("sendfile: convert nfsd to
splice_direct_to_actor()").
Link: https://lkml.kernel.org/r/20210325114228.27719-7-mgorman@techsingularity.net
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/sunrpc/svc_xprt.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 42565f0c7d5a..63eb6b9a4973 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -661,7 +661,7 @@ static void svc_check_conn_limits(struct svc_serv *serv) static int svc_alloc_arg(struct svc_rqst *rqstp) { struct svc_serv *serv = rqstp->rq_server; - struct xdr_buf *arg; + struct xdr_buf *arg = &rqstp->rq_arg; int pages; int i; @@ -686,11 +686,10 @@ static int svc_alloc_arg(struct svc_rqst *rqstp) } rqstp->rq_pages[i] = p; } - rqstp->rq_page_end = &rqstp->rq_pages[i]; - rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */ + rqstp->rq_page_end = &rqstp->rq_pages[pages]; + rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */ /* Make arg->head point to first page and arg->pages point to rest */ - arg = &rqstp->rq_arg; arg->head[0].iov_base = page_address(rqstp->rq_pages[0]); arg->head[0].iov_len = PAGE_SIZE; arg->pages = rqstp->rq_pages + 1; |