lkml.org 
[lkml]   [2020]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[RFC/RFT PATCH v2 0/1] arc: add sparsemem support
Date
From: Mike Rapoport <rppt@linux.ibm.com>

Hi,

It took me a while to get back to it, but better late than never :)

This patch adds SPARSEMEM support as an alternative to DISCONTIGMEM in
the case when there are two DRAM banks populated.

I've verified that it boots on nsim, but I could not find a way to make
nsim emulate two memory banks.

There is slight improvement in the resulting kernel size for
nsim_700_defconfig with CONFIG_HIGHMEM=y.

If sparse actually works on a system with 2 DRAM banks and does not
introduce performance regression, I suggest to update this patch to
replace DISCONTIGMEM with SPARSEMEM on arc.

$ size discontig/vmlinux sparse/vmlinux
text data bss dec hex filename
3894379 1093092 244932 5232403 4fd713 discontig/vmlinux
3879040 1093964 244956 5217960 4f9ea8 sparse/vmlinux

$ ./scripts/bloat-o-meter ~/tmp/arc/discontig/vmlinux ~/tmp/arc/sparse/vmlinux
add/remove: 35/23 grow/shrink: 35/384 up/down: 8110/-26438 (-18328)
...
Total: Before=4282217, After=4263889, chg -0.43%


Mike Rapoport (1):
arc: add sparsemem support

arch/arc/Kconfig | 10 ++++++++++
arch/arc/include/asm/sparsemem.h | 13 +++++++++++++
arch/arc/mm/init.c | 7 ++++++-
3 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 arch/arc/include/asm/sparsemem.h

--
2.26.2

\
 
 \ /
  Last update: 2020-07-09 15:45    [W:0.026 / U:1.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site