From: Mike Rapoport <rppt@kernel.org>
To: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org,
Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>,
linux-kernel@vger.kernel.org, Mike Rapoport <rppt@kernel.org>,
Mike Rapoport <rppt@linux.ibm.com>
Subject: [RFC/RFT PATCH v2 0/1] arc: add sparsemem support
Date: Thu, 9 Jul 2020 16:44:11 +0300 [thread overview]
Message-ID: <20200709134412.1464453-1-rppt@kernel.org> (raw)
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
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next reply other threads:[~2020-07-09 13:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 13:44 Mike Rapoport [this message]
2020-07-09 13:44 ` [RFC/RFT PATCH v2 1/1] arc: add sparsemem support Mike Rapoport
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