Chuck Lever ab8362645f 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 cf8208d0ea ("sendfile: convert nfsd to
splice_direct_to_actor()").

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Chuck Lever <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Reviewed-by: Alexander Lobakin <[email protected]>
Cc: Alexander Duyck <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: David Miller <[email protected]>
Cc: Ilias Apalodimas <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
2021-04-30 11:20:43 -07:00
2021-01-24 14:27:20 +01:00
2021-04-30 11:20:43 -07:00

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