From mboxrd@z Thu Jan 1 00:00:00 1970 From: tom.zanussi@linux.intel.com (Tom Zanussi) Date: Tue, 04 Apr 2017 12:59:09 -0500 Subject: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems In-Reply-To: References: <20170401222119.25106-1-nicolas.pitre@linaro.org> <87pogur0y9.fsf@firstfloor.org> <92fb1e4a-d6df-f55b-c0a1-9c1eb78e3943@longlandclan.id.au> <1491325150.7125.62.camel@tzanussi-mobl.amr.corp.intel.com> Message-ID: <1491328749.7125.66.camel@tzanussi-mobl.amr.corp.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2017-04-04 at 20:08 +0300, Andy Shevchenko wrote: > On Tue, Apr 4, 2017 at 7:59 PM, Tom Zanussi wrote: > > On Tue, 2017-04-04 at 00:05 +0300, Andy Shevchenko wrote: > > > Yes, in a previous project, I had been working toward getting a < 1M > > system to boot on Galileo hardware (which it did, but using more than > > that - the Galileo2 has 256MB, but it was the target hardware at the > > time, and I was hoping eventually to be able to boot out of the 512k > > on-chip SRAM). > > > > I was focused at that point mainly on the kernel static size, and using > > a combination of Josh Triplett's tinification tree, Andi Kleen's LTO and > > net-diet patches, and my own miscellaneous patches that I was planning > > on eventually upstreaming, I ended up with a system that I could boot to > > shell with a 455k text size: > > > > Memory: 235636K/245176K available (455K kernel code, 61K rwdata, > > 64K rodata, 132K init, 56K bss, 3056K reserved, 0K cma-reserved) > > > > virtual kernel memory layout: > > fixmap : 0xfffe5000 - 0xfffff000 ( 104 kB) > > vmalloc : 0xd05f0000 - 0xfffe3000 ( 761 MB) > > lowmem : 0xc0000000 - 0xcfdf0000 ( 253 MB) > > .init : 0xc1094000 - 0xc10b5000 ( 132 kB) > > .data : 0xc1071fac - 0xc1092760 ( 129 kB) > > .text : 0xc1000000 - 0xc1071fac ( 455 kB) > > > > That was without networking. Enabling networking added about 250k, and > > at that point I could ssh in and run a webserver, still less than 1M as > > far as kernel static size, which of course completely ignores the kernel > > dynamic size and userspace. > > Thanks for sharing your experience. The question closer to this > discussion what did you do against TTY/UART/(related) layer(s)? > I'd have to go back and take a look, but nothing special AFIAR. No patches or hacks along those lines, and the only related thing I see as far as config is: cfg/pty-disable.scc \ which maps to: # CONFIG_UNIX98_PTYS is not set