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0796ddf4a7
The cpuidle governor callbacks for update, select and reflect
are always running on the actual idle entering/exiting CPU, so
use the more optimized this_cpu_ptr() to access the internal teo
data.
This brings down the latency-critical teo_reflect() from
static void teo_reflect(struct cpuidle_device *dev, int state)
{
ffffffc080ffcff0: hint #0x19
ffffffc080ffcff4: stp x29, x30, [sp, #-48]!
struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
ffffffc080ffcff8: adrp x2, ffffffc0848c0000 <gicv5_global_data+0x28>
{
ffffffc080ffcffc: add x29, sp, #0x0
ffffffc080ffd000: stp x19, x20, [sp, #16]
ffffffc080ffd004: orr x20, xzr, x0
struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
ffffffc080ffd008: add x0, x2, #0xc20
{
ffffffc080ffd00c: stp x21, x22, [sp, #32]
struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
ffffffc080ffd010: adrp x19, ffffffc083eb5000 <cpu_devices+0x78>
ffffffc080ffd014: add x19, x19, #0xbb0
ffffffc080ffd018: ldr w3, [x20, #4]
dev->last_state_idx = state;
to
static void teo_reflect(struct cpuidle_device *dev, int state)
{
ffffffc080ffd034: hint #0x19
ffffffc080ffd038: stp x29, x30, [sp, #-48]!
ffffffc080ffd03c: add x29, sp, #0x0
ffffffc080ffd040: stp x19, x20, [sp, #16]
ffffffc080ffd044: orr x20, xzr, x0
struct teo_cpu *cpu_data = this_cpu_ptr(&teo_cpus);
ffffffc080ffd048: adrp x19, ffffffc083eb5000 <cpu_devices+0x78>
{
ffffffc080ffd04c: stp x21, x22, [sp, #32]
struct teo_cpu *cpu_data = this_cpu_ptr(&teo_cpus);
ffffffc080ffd050: add x19, x19, #0xbb0
dev->last_state_idx = state;
This saves us:
adrp x2, ffffffc0848c0000 <gicv5_global_data+0x28>
add x0, x2, #0xc20
ldr w3, [x20, #4]
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
[ rjw: Subject tweak ]
Link: https://patch.msgid.link/20251110120819.714560-1-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.