According to Ingo's and Eric's advice[1,2], Try my best to optimize the
init of interrupt delivery mode for x86.
MP specification defines three different interrupt modes as follows:
1. PIC Mode
2. Virtual Wire Mode
3. Symmetric I/O Mode
Currently, in kernel,
1. Setup Virtual Wire Mode during IRQ initialization( step 1
in the following figure).
2. Enable and Setup Symmetric I/O Mode either during the
SMP-capable system prepares CPUs(step 2) or during the UP system
initializes itself(step 3).
start_kernel
+---------------+
|
+--> .......
|
| setup_arch
+--> +-------+
|
| init_IRQ
+-> +--+-----+
| | init_ISA_irqs
| +------> +-+--------+
| | +----------------+
+---> +------> | 1.init_bsp_APIC|
| ....... +----------------+
+--->
| rest_init
+--->---+-----+
| | kernel_init
| +> ----+-----+
| | kernel_init_freeable
| +-> ----+-------------+
| | smp_prepare_cpus
| +---> +----+---------+
| | | +-------------------+
| | +-> |2. apic_bsp_setup |
| | +-------------------+
| |
v | smp_init
+---> +---+----+
| +-------------------+
+--> |3. apic_bsp_setup |
+-------------------+
The purpose of this patchset is unifying these setup steps and executing
as soon as possible as follows:
start_kernel
---------------+
|
|
|
| x86_late_time_init
+---->---+------------+
| |
| | +------------------------+
| +----> | 4. init_interrupt_mode |
| +------------------------+
v
By the way, Also fix a bug about kexec[3].
[1]. https://lkml.org/lkml/2016/8/2/929
[2]. https://lkml.org/lkml/2016/8/1/506
[3]. https://lkml.org/lkml/2016/7/25/1118
Changes since V1:
- Move the initialization from init_IRQ() to x86_late_time_init()
- Use a threshold to refactor the check logic in timer_irq_works()
- Rename the framework to a selector
- Split two patches
- Consistently start sentences with upper case letters
- Fix some typos
- Rewrite the changelog
Dou Liyang (12):
x86/apic: Replace init_bsp_APIC() with apic_virtual_wire_mode_setup()
x86/apic: Construct a selector for the interrupt delivery mode
x86/apic: Prepare for unifying the interrupt delivery modes setup
x86/time: Initialize interrupt mode behind timer init
x86/ioapic: Refactor the delay logic in timer_irq_works()
x86/apic: Split local APIC timer setup from the APIC setup
x86/apic: Move the logical APIC ID setup from apic_bsp_setup()
x86/apic: Make the interrupt mode setup earlier for SMP-capable system
x86/apic: Setup interrupt mode earlier in case of no SMP motherboard
x86/apic: Make the interrupt mode setup earlier for UP system
x86/apic: Mark the apic_interrupt_mode extern for refining code
x86/apic: Remove the apic_virtual_wire_mode_setup()
arch/x86/include/asm/apic.h | 14 +++-
arch/x86/kernel/apic/apic.c | 183 +++++++++++++++++++++--------------------
arch/x86/kernel/apic/io_apic.c | 47 +++++++++--
arch/x86/kernel/irqinit.c | 3 -
arch/x86/kernel/smpboot.c | 64 +++-----------
arch/x86/kernel/time.c | 8 ++
6 files changed, 168 insertions(+), 151 deletions(-)
--
2.5.5
