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From: Borislav Petkov <bp@alien8.de>
To: Ashish Kalra <ashish.kalra@amd.com>
Cc: Thomas.Lendacky@amd.com, Jon.Grimm@amd.com,
	brijesh.singh@amd.com, dave.hansen@linux-intel.com,
	konrad.wilk@oracle.com, peterz@infradead.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	mingo@redhat.com, luto@kernel.org, hpa@zytor.com,
	rientjes@google.com, tglx@linutronix.de, hch@lst.de
Subject: Re: [PATCH v7] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests.
Date: Mon, 7 Dec 2020 23:14:33 +0100	[thread overview]
Message-ID: <20201207221433.GI20489@zn.tnic> (raw)
In-Reply-To: <20201207220624.GB6855@ashkalra_ubuntu_server>

On Mon, Dec 07, 2020 at 10:06:24PM +0000, Ashish Kalra wrote:
> This is related to the earlier static adjustment of the SWIOTLB buffers
> as per guest memory size and Konrad's feedback on the same, as copied
> below : 
> 
> >>That is eating 128MB for 1GB, aka 12% of the guest memory allocated statically for this.
> >> 
> >> And for guests that are 2GB, that is 12% until it gets to 3GB when 
> >> it is 8% and then 6% at 4GB.
> >> 
> >> I would prefer this to be based on your memory count, that is 6% of 
> >> total memory.

So no rule of thumb and no measurements? Just a magic number 6.

Btw, pls trim the rest of the mail when you reply. Like I just did.
There's no need to leave text which you're not responding to, quoted.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette
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  reply	other threads:[~2020-12-07 22:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03  3:25 [PATCH v7] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests Ashish Kalra
2020-12-07 12:10 ` Borislav Petkov
2020-12-07 22:06   ` Ashish Kalra
2020-12-07 22:14     ` Borislav Petkov [this message]
2020-12-07 22:20       ` Kalra, Ashish
2020-12-07 22:33         ` Borislav Petkov

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