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

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Message-ID: <aMg6oK6gaUfU9ol2@kernel.org>
Date: Mon, 15 Sep 2025 19:11:12 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Jason Gunthorpe <jgg@...dia.com>
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 11:37:30AM -0300, Jason Gunthorpe wrote:
> 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.

But we don't care here, we free that page immediately to buddy on
restoration.
 
> Jason

-- 
Sincerely yours,
Mike.