From: Gavin Shan <gshan@redhat.com>
To: linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, will@kernel.org,
catalin.marinas@arm.com, shan.gavin@gmail.com,
sudeep.holla@arm.com, robin.murphy@arm.com
Subject: [PATCH v5 0/4] arm64: Dereference CPU operations indirectly
Date: Thu, 19 Mar 2020 10:01:41 +1100 [thread overview]
Message-ID: <20200318230145.72097-1-gshan@redhat.com> (raw)
The subject perhaps can't precisely indicate what this series does, but
keep it same as before for consistency.
In current implementation, an array (@cpu_ops[NR_CPUS]) is maintained
to dereference the CPU operations. 2KB memory are consumed when NR_CPUS
is configured to 256. It's too much than what I expected. This series
reworks the implementation to dereference the CPU operations by using
two CPU operations pointer with assumption - all secondary CPUs should
have unified CPU operations. With this, 16-bytes memory will be used
for same purpose.
PATCH[1/4] isn't too much relevant, to declare ACPI parking protocol only
when CONFIG_ARM64_ACPI_PARKING_PROTOCOL has been enabled. PATCH[2/4]
renames cpu_read_ops() to init_cpu_ops(), which is obviously more precise
because it's initializing the CPU operations. PATCH[3/4] introduces
get_cpu_ops(), preparing for droping the array of CPU operations.
PATCH[4/4] removes the CPU operations deferencing array and replaces
it with two pointers with the assumption: all secondary CPUs should have
same enablement method.
Changelog
=========
v5:
* Rebase to 5.6.rc6 and retest (Gavin Shan)
* Improved commit log for PATCH[1] (Gavin Shan)
* Add helper function __cpu_try_die() (Mark Rutland)
* Two pointers to track the operations for boot CPU
and the secondary CPUs separately (Mark Rutland)
* Drop PATCH[5] because @cpu parameter is still
needed by get_cpu_ops() (Gavin Shan)
v4:
* Rebase to 5.6.rc3 and retest (Gavin Shan)
* Improved commit log for PATCH[4/5] with link tag (Lorenzo Pieralisi)
* Using pointer instead of index to dereference the
unified CPU operations (Lorenzo Pieralisi)
* Merge logic of cpu_get_ops() to get_cpu_method() (Gavin Shan)
v3:
* Assume all CPUs have same enablement method. With this, the used
memory is further squeezed from 64 bytes to 4 bytes (Lorenzo Pieralisi)
* Add PATCH[5/5] to remove argument of get_cpu_ops() (Gavin Shan)
v2:
* Pack 4 CPUs' indexes into one byte. 64 bytes are consumed in order
to get the CPU operations (Robin Murphy)
* Use ARRAY_SIZE() to iterate @cpu_ops[] (Robin Murphy)
* Make index-0 valid (Robin Murphy)
Gavin Shan (4):
arm64: Declare ACPI parking protocol CPU operation if needed
arm64: Rename cpu_read_ops() to init_cpu_ops()
arm64: Introduce get_cpu_ops() helper function
arm64: Remove CPU operations dereferencing array
arch/arm64/include/asm/cpu_ops.h | 8 +--
arch/arm64/kernel/cpu_ops.c | 84 +++++++++++++++++---------------
arch/arm64/kernel/cpuidle.c | 9 ++--
arch/arm64/kernel/setup.c | 8 +--
arch/arm64/kernel/smp.c | 72 +++++++++++++++++----------
5 files changed, 107 insertions(+), 74 deletions(-)
--
2.23.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-03-18 23:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 23:01 Gavin Shan [this message]
2020-03-18 23:01 ` [PATCH v5 1/4] arm64: Declare ACPI parking protocol CPU operation if needed Gavin Shan
2020-03-18 23:01 ` [PATCH v5 2/4] arm64: Rename cpu_read_ops() to init_cpu_ops() Gavin Shan
2020-03-18 23:01 ` [PATCH v5 3/4] arm64: Introduce get_cpu_ops() helper function Gavin Shan
2020-03-19 19:31 ` Mark Rutland
2020-03-18 23:01 ` [PATCH v5 4/4] arm64: Remove CPU operations dereferencing array Gavin Shan
2020-03-19 19:38 ` Mark Rutland
2020-03-19 22:54 ` Gavin Shan
2020-03-24 17:29 ` [PATCH v5 0/4] arm64: Dereference CPU operations indirectly Catalin Marinas
2020-03-25 11:49 ` Gavin Shan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200318230145.72097-1-gshan@redhat.com \
--to=gshan@redhat.com \
--cc=catalin.marinas@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=lorenzo.pieralisi@arm.com \
--cc=mark.rutland@arm.com \
--cc=robin.murphy@arm.com \
--cc=shan.gavin@gmail.com \
--cc=sudeep.holla@arm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).