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

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Message-ID: <aMhAiR6qnXMA-c8r@kernel.org>
Date: Mon, 15 Sep 2025 19:36:25 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Jason Gunthorpe <jgg@...dia.com>
Cc: Pratyush Yadav <me@...avpratyush.com>,
	Pratyush Yadav <pratyush@...nel.org>,
	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>,
	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 11:43:35AM -0300, Jason Gunthorpe wrote:
> On Mon, Sep 15, 2025 at 05:12:27PM +0300, Mike Rapoport wrote:
> > > I don't suppose I'd insist on it, but something to consider since you
> > > are likely going to do another revision anyway.
> > 
> > I think vmalloc is as basic as folio.
> 
> vmalloc() ultimately calls vm_area_alloc_pages() -> alloc_pages_bulk_node_noprof()
> 
> KHO should have functions that clearly pair with the low level
> allocators struct page related allocators, alloc_pages(order),
> folio_alloc(), etc etc
> 
> ie if you call this allocator X then you call this kho preserve, this
> kho restore, and this free function Y.
> 
> Under the covers it all uses the generic folio based code we already
> have, but we should have appropriate wrappers around that code that
> make clear these patterns.

Right, but that does not mean that vmalloc preserve/restore should use the
public KHO APIs and avoid using internal methods.
 
> Jason

-- 
Sincerely yours,
Mike.