linux-kernel - Re: [PATCH v3 1/2] kho: add support for preserving vmalloc allocations

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Message-ID: <20250915143730.GK1024672@nvidia.com>
Date: Mon, 15 Sep 2025 11:37:30 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Mike Rapoport <rppt@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Alexander Graf <graf@...zon.com>, Baoquan He <bhe@...hat.com>,
	Changyuan Lyu <changyuanl@...gle.com>, Chris Li <chrisl@...nel.org>,
	Pasha Tatashin <pasha.tatashin@...een.com>,
	Pratyush Yadav <pratyush@...nel.org>, kexec@...ts.infradead.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] kho: add support for preserving vmalloc
 allocations

On Mon, Sep 15, 2025 at 05:01:01PM +0300, Mike Rapoport wrote:
> > kzalloc() cannot be preserved, the only thing we support today is
> > alloc_page(), so this code pattern shouldn't exist.
>  
> kzalloc(PAGE_SIZE) can be preserved, it's page aligned and we don't have to
> restore it into a slab cache. But this maybe indeed confusing for those who
> copy paste the code, so I'll change it.

It really isn't. The kzalloc should be returning frozen pages for that
allocation and the restoration will not put frozen pages back.

Jason