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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "ajd@linux.ibm.com" <ajd@linux.ibm.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	"ardb@kernel.org" <ardb@kernel.org>,
	"jbaron@akamai.com" <jbaron@akamai.com>,
	"npiggin@gmail.com" <npiggin@gmail.com>,
	Benjamin Gray <bgray@linux.ibm.com>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"jpoimboe@kernel.org" <jpoimboe@kernel.org>
Subject: Re: [PATCH v3 5/6] powerpc/64: Add support for out-of-line static calls
Date: Thu, 6 Oct 2022 15:45:33 -0500	[thread overview]
Message-ID: <20221006204533.GU25951@gate.crashing.org> (raw)
In-Reply-To: <2bb8accb-30c0-67e6-7ad5-36c02d46a2cd@csgroup.eu>

On Thu, Oct 06, 2022 at 06:38:00PM +0000, Christophe Leroy wrote:
> Le 06/10/2022 à 20:22, Segher Boessenkool a écrit :
> > Long ago I built kernels that fit together with the boot firmware and a
> > root fs (busybox+dropbear essentially) in 4MB, but I doubt we can get
> > close to that at all these days :-)
> 
> 4MB, not easy. But 8M still achievable. Well our smaller board has 32M, 
> we have thousands of it spread all over Europe and have to keep it up to 
> date ....

The smallest of these systems had 256MB RAM.  This 4MB is flash ROM :-)

> > What is the overhead if you enable modules but do not use them, these
> > days?
> 
> On the 8xx it is mainly the instruction TLB miss handler:

I meant just an indicative code size number...  100 bytes, 100kB, 100MB,
or something like that :-)  And, on 64 bit, which is what the question
was about!


Segher

  reply	other threads:[~2022-10-06 20:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-05  5:32 [PATCH v3 0/6] Out-of-line static calls for powerpc64 ELF V2 Benjamin Gray
2022-10-05  5:32 ` [PATCH v3 1/6] powerpc/code-patching: Implement generic text patching function Benjamin Gray
2022-10-05 17:55   ` Christophe Leroy
2022-10-06  3:36     ` Benjamin Gray
2022-10-06  9:19       ` Christophe Leroy
2022-10-06 21:53         ` Benjamin Gray
2022-10-05  5:32 ` [PATCH v3 2/6] powerpc/module: Handle caller-saved TOC in module linker Benjamin Gray
2022-10-05 19:18   ` Christophe Leroy
2022-10-06  3:51     ` Andrew Donnellan
2022-10-06  4:39     ` Benjamin Gray
2022-10-05  5:32 ` [PATCH v3 3/6] powerpc/module: Optimise nearby branches in ELF V2 ABI stub Benjamin Gray
2022-10-05 19:21   ` Christophe Leroy
2022-10-06  8:24   ` Andrew Donnellan
2022-10-05  5:32 ` [PATCH v3 4/6] static_call: Move static call selftest to static_call_selftest.c Benjamin Gray
2022-10-05 19:22   ` Christophe Leroy
2022-10-05  5:32 ` [PATCH v3 5/6] powerpc/64: Add support for out-of-line static calls Benjamin Gray
2022-10-05 19:38   ` Christophe Leroy
2022-10-06  0:39     ` Michael Ellerman
2022-10-06  5:01       ` Benjamin Gray
2022-10-06 18:22       ` Segher Boessenkool
2022-10-06 18:38         ` Christophe Leroy
2022-10-06 20:45           ` Segher Boessenkool [this message]
2022-10-06 20:50             ` Christophe Leroy
2022-10-06 21:04               ` Segher Boessenkool
2022-10-05  5:32 ` [PATCH v3 6/6] powerpc: Add tests " Benjamin Gray

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