Re: [PATCH bpf-next v2 0/5] execmem_alloc for BPF programs

From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "song@kernel.org" <song@kernel.org>
Cc: "peterz@infradead.org" <peterz@infradead.org>,
	"rppt@kernel.org" <rppt@kernel.org>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"hch@lst.de" <hch@lst.de>, "x86@kernel.org" <x86@kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"mcgrof@kernel.org" <mcgrof@kernel.org>,
	"Lu, Aaron" <aaron.lu@intel.com>
Subject: Re: [PATCH bpf-next v2 0/5] execmem_alloc for BPF programs
Date: Tue, 15 Nov 2022 22:14:20 +0000	[thread overview]
Message-ID: <4bf1a1377ea39f287a4fd438d81f314d261f7d7f.camel@intel.com> (raw)
In-Reply-To: <CAPhsuW7H95hUUCGEk9etwTT8kYRCKCtD6Lo+8WxHUyGTKSyEFA@mail.gmail.com>

On Tue, 2022-11-15 at 13:54 -0800, Song Liu wrote:
> On Tue, Nov 15, 2022 at 9:34 AM Edgecombe, Rick P
> <rick.p.edgecombe@intel.com> wrote:
> > 
> > On Mon, 2022-11-14 at 17:30 -0800, Song Liu wrote:
> > > Currently, I have got the following action items for v3:
> > > 1. Add unify API to allocate text memory to motivation;
> > > 2. Update Documentation/x86/x86_64/mm.rst;
> > > 3. Allow none PMD_SIZE allocation for powerpc.
> > 
> > So what do we think about supporting the fallback mechanism for the
> > first version, like:
> > 
> > 
https://lore.kernel.org/all/9e59a4e8b6f071cf380b9843cdf1e9160f798255.camel@intel.com/
> > 
> > It helps the (1) story by actually being usable by non-text_poke()
> > architectures.
> 
> I personally think this might be a good idea. We will need this when
> we use
> execmem_alloc for modules. But I haven't got a chance to look at
> module code in
> great detail. I was thinking of adding this logic with changes in
> module code.

BPF used to have a generic allocator that just called module_alloc().
If you had a fallback method could you unify all of BPF to use
execmem()?