From: Peter Zijlstra <peterz@infradead.org>
To: Song Liu <songliubraving@fb.com>
Cc: Linux-MM <linux-mm@kvack.org>,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
X86 ML <x86@kernel.org>, Christoph Hellwig <hch@lst.de>,
Kernel Team <Kernel-team@fb.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Dave Hansen <dave.hansen@intel.com>, Song Liu <song@kernel.org>
Subject: Re: [RFC 0/5] vmalloc_exec for modules and BPF programs
Date: Tue, 23 Aug 2022 07:42:59 +0200 [thread overview]
Message-ID: <YwRo43EBIWh7++Qn@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <7621DE6E-D71D-45D1-BAFA-46E882451DD9@fb.com>
On Mon, Aug 22, 2022 at 04:56:47PM +0000, Song Liu wrote:
>
>
> > On Aug 22, 2022, at 9:34 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Mon, Aug 22, 2022 at 03:46:38PM +0000, Song Liu wrote:
> >> Could you please share your feedback on this?
> >
> > I've looked at it all of 5 minutes, so perhaps I've missed something.
> >
> > However, I'm a little surprised you went with a second tree instead of
> > doing the top-down thing for data. The way you did it makes it hard to
> > have guard pages between text and data.
>
> I didn't realize the importance of the guard pages. But it is not too
I'm not sure how important it is, just seems like a good idea to trap
anybody trying to cross that divide. Also, to me it seems like a good
idea to have a single large contiguous text region instead of splintered
2M pages.
> hard to do it with this approach. For each 2MB text page, we can reserve
> 4kB on the beginning and end of it. Would this work?
Typically a guard page has different protections (as in none what so
ever) so that every access goes *splat*.
next prev parent reply other threads:[~2022-08-23 5:43 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-18 22:42 Song Liu
2022-08-18 22:42 ` [RFC 1/5] vmalloc: introduce vmalloc_exec and vfree_exec Song Liu
2022-10-06 23:15 ` Luis Chamberlain
2022-10-07 6:39 ` Song Liu
2022-08-18 22:42 ` [RFC 2/5] bpf: use vmalloc_exec Song Liu
2022-08-18 22:42 ` [RFC 3/5] modules, x86: use vmalloc_exec for module core Song Liu
2022-10-06 23:38 ` Luis Chamberlain
2022-10-07 6:46 ` Song Liu
2022-08-18 22:42 ` [RFC 4/5] vmalloc_exec: share a huge page with kernel text Song Liu
2022-10-06 23:44 ` Luis Chamberlain
2022-10-07 6:53 ` Song Liu
2022-08-18 22:42 ` [RFC 5/5] vmalloc: vfree_exec: free unused vm_struct Song Liu
2022-08-22 15:46 ` [RFC 0/5] vmalloc_exec for modules and BPF programs Song Liu
2022-08-22 16:34 ` Peter Zijlstra
2022-08-22 16:56 ` Song Liu
2022-08-23 5:42 ` Peter Zijlstra [this message]
2022-08-23 6:39 ` Christophe Leroy
2022-08-23 6:57 ` Song Liu
2022-08-23 6:55 ` Song Liu
2022-08-24 17:06 ` Song Liu
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