From: Peter Zijlstra <peterz@infradead.org>
To: Song Liu <songliubraving@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
the arch/x86 maintainers <x86@kernel.org>,
bpf <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"ast@kernel.org" <ast@kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"andrii@kernel.org" <andrii@kernel.org>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 2/7] set_memory: introduce set_memory_[ro|x]_noalias
Date: Thu, 18 Nov 2021 08:54:47 +0100 [thread overview]
Message-ID: <20211118075447.GG174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <73EBD706-4FEC-4976-9041-036EB3032478@fb.com>
On Wed, Nov 17, 2021 at 11:57:12PM +0000, Song Liu wrote:
> I would agree that __text_poke() is a safer option. But in this case, we
> will need the temporary hole to be 2MB in size. Also, we will probably
> hold the temporary mapping for longer time (the whole JITing process).
> Does this sound reasonable?
No :-)
Jit to a buffer, then copy the buffer into the 2M page using 4k aliases.
IIRC each program is still smaller than a single page, right? So at no
point do you need more than 2 pages mapped anyway.
next prev parent reply other threads:[~2021-11-18 7:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20211116071347.520327-1-songliubraving@fb.com>
[not found] ` <20211116071347.520327-3-songliubraving@fb.com>
2021-11-16 8:00 ` [PATCH bpf-next 2/7] set_memory: introduce set_memory_[ro|x]_noalias Peter Zijlstra
2021-11-17 21:36 ` Song Liu
2021-11-17 22:01 ` Peter Zijlstra
2021-11-17 23:57 ` Song Liu
2021-11-18 0:11 ` Song Liu
2021-11-18 7:54 ` Peter Zijlstra [this message]
2021-11-18 17:16 ` Song Liu
2021-11-18 18:28 ` Peter Zijlstra
2021-11-18 18:39 ` Song Liu
2021-11-18 18:58 ` Peter Zijlstra
2021-11-19 4:14 ` Song Liu
2021-11-19 9:35 ` Peter Zijlstra
2021-11-19 16:06 ` Johannes Weiner
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