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Message-ID: <20250403114209.GE342109@nvidia.com>
Date: Thu, 3 Apr 2025 08:42:09 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Pratyush Yadav <ptyadav@...zon.de>
Cc: Changyuan Lyu <changyuanl@...gle.com>, linux-kernel@...r.kernel.org,
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Subject: Re: [PATCH v5 09/16] kexec: enable KHO support for memory
preservation
On Wed, Apr 02, 2025 at 07:16:27PM +0000, Pratyush Yadav wrote:
> > +int kho_preserve_phys(phys_addr_t phys, size_t size)
> > +{
> > + unsigned long pfn = PHYS_PFN(phys), end_pfn = PHYS_PFN(phys + size);
> > + unsigned int order = ilog2(end_pfn - pfn);
>
> This caught my eye when playing around with the code. It does not put
> any limit on the order, so it can exceed NR_PAGE_ORDERS. Also, when
> initializing the page after KHO, we pass the order directly to
> prep_compound_page() without sanity checking it. The next kernel might
> not support all the orders the current one supports. Perhaps something
> to fix?
IMHO we should delete the phys functions until we get a user of them
Jason
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