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From: Christoph Hellwig <hch@lst.de>
To: David Daney <ddaney@caviumnetworks.com>
Cc: Christoph Hellwig <hch@lst.de>,
	George Cherian <gcherian@caviumnetworks.com>,
	George Cherian <george.cherian@cavium.com>,
	David Daney <david.daney@cavium.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: crypto/cavium MSI-X fixups
Date: Wed, 22 Feb 2017 08:27:52 +0100	[thread overview]
Message-ID: <20170222072752.GA18643@lst.de> (raw)
In-Reply-To: <52c432c9-4dc1-861e-5556-0db2f4a42c98@caviumnetworks.com>

On Tue, Feb 21, 2017 at 09:36:04AM -0800, David Daney wrote:
> With respect to pci_enable_msix(), what do you recommend as a replacement?  

pci_alloc_irq_vectors.  In fact I have a tree ready for after -rc1
that removes pci_enable_msix() entirely.

> For the crypto/cavium driver, you recommend pci_alloc_irq_vectors(), which 
> works well if the required MSI-X indexes are contiguous starting at zero.   
> What would be used for a device that has 184 MSI-X, but only a sparse 
> subset (fewer than half) of these are required for the driver operation.  
> It would waste system resources to use an API that forces us to allocate 
> 184 when only 80 are required.

Currently we don't have a good API for that.  I've not been through all
users of pci_enable_msix_{range,exact} yet, but so far I've only found
one user not using all vectors from 0 to some limit.  Depending how many
such users we have and how they'll look I will have to look into an API
to support that use case.

  reply	other threads:[~2017-02-22  7:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-15  7:18 crypto/cavium MSI-X fixups Christoph Hellwig
2017-02-15  7:18 ` [PATCH 1/3] crypto: cavium: remove dead MSI-X related define Christoph Hellwig
2017-02-15  7:18 ` [PATCH 2/3] crypto: cavium/cptpf: switch to pci_alloc_irq_vectors Christoph Hellwig
2017-02-15  7:18 ` [PATCH 3/3] crypto: cavium/cptvf: " Christoph Hellwig
2017-02-15  9:17 ` crypto/cavium MSI-X fixups George Cherian
2017-02-19 17:32   ` Christoph Hellwig
2017-02-21 17:36     ` David Daney
2017-02-22  7:27       ` Christoph Hellwig [this message]
2017-02-22 17:45         ` David Daney
2017-02-23 12:16 ` Herbert Xu

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