From: Jason Gunthorpe <jgg@ziepe.ca>
To: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
Palmer Dabbelt <palmer@sifive.com>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Ming Lei <ming.lei@redhat.com>,
Gal Pressman <galpress@amazon.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] scatterlist: Speed up for_each_sg() loop macro
Date: Mon, 28 Oct 2019 11:17:34 -0300 [thread overview]
Message-ID: <20191028141734.GD29652@ziepe.ca> (raw)
In-Reply-To: <20191025213359.7538-1-sultan@kerneltoast.com>
On Fri, Oct 25, 2019 at 02:33:58PM -0700, Sultan Alsawaf wrote:
>
> Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
> include/linux/scatterlist.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
> index 556ec1ea2574..73f7fd6702d7 100644
> +++ b/include/linux/scatterlist.h
> @@ -146,7 +146,10 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
> * Loop over each sg element, following the pointer to a new list if necessary
> */
> #define for_each_sg(sglist, sg, nr, __i) \
> - for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
> + for (__i = 0, sg = (sglist); __i < (nr); \
> + likely(++__i % (SG_MAX_SINGLE_ALLOC - 1) || \
> + (__i + 1) >= (nr)) ? sg++ : \
> + (sg = sg_chain_ptr(sg + 1)))
This is a big change in the algorithm, why are you sure it is OK?
Did you compare with just inlining sg_net?
Jason
next prev parent reply other threads:[~2019-10-28 14:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 21:33 [PATCH] scatterlist: Speed up for_each_sg() loop macro Sultan Alsawaf
2019-10-28 14:17 ` Jason Gunthorpe [this message]
2019-10-28 16:18 ` Sultan Alsawaf
2019-10-28 16:23 ` Jason Gunthorpe
2019-10-28 16:28 ` Christoph Hellwig
2019-10-28 16:37 ` Sultan Alsawaf
2019-10-28 16:29 ` Sultan Alsawaf
2019-10-28 23:46 ` kbuild test robot
2019-10-28 23:46 ` kbuild test robot
2019-10-29 2:25 ` Ming Lei
2019-11-01 3:33 ` [scatterlist] 8f39742f03: suspend_stress.fail kernel test robot
2019-11-01 3:33 ` kernel test robot
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