mywiki:linux:linux_kernel_notes
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| mywiki:linux:linux_kernel_notes [2015/06/08 17:58] – shaoguoh | mywiki:linux:linux_kernel_notes [2019/09/15 18:55] (current) – external edit 127.0.0.1 | ||
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| - | ====== Spin Lock ====== | ||
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| - | ===== Table of Minimum Spin Lock Requirements ===== | ||
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| - | The following table lists the minimum locking requirements between various contexts. In some cases, the same context can only be running on one CPU at a time, so no locking is required for that context (eg. a particular thread can only run on one CPU at a time, but if it needs shares data with another thread, locking is required). \\ | ||
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| - | Remember the advice above: you can always use spin_lock_irqsave(), | ||
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| - | | | IRQ Handler A | IRQ Handler B | Softirq A | Softirq B | Tasklet A | Tasklet B | Timer A | Timer B | User Context A | User Context B | | ||
| - | | IRQ Handler A | None | | ||
| - | | IRQ Handler B | spin_lock_irqsave | None | | ||
| - | | Softirq A | spin_lock_irq | spin_lock_irq | spin_lock | | ||
| - | | Softirq B | spin_lock_irq | spin_lock_irq | spin_lock | spin_lock | | ||
| - | | Tasklet A | spin_lock_irq | spin_lock_irq | spin_lock | spin_lock | None | | ||
| - | | Tasklet B | spin_lock_irq | spin_lock_irq | spin_lock | spin_lock | spin_lock | None | | ||
| - | | Timer A | spin_lock_irq | spin_lock_irq | spin_lock | spin_lock | spin_lock | spin_lock | None | | ||
| - | | Timer B | spin_lock_irq | spin_lock_irq | spin_lock | spin_lock | spin_lock | spin_lock | spin_lock | None | | ||
| - | | User Context A | spin_lock_irq | spin_lock_irq | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | None | | ||
| - | | User Context B | spin_lock_irq | spin_lock_irq | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | spin_lock_bh | down_interruptible | None | | ||
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| ===== Kernel Context knowledge ===== | ===== Kernel Context knowledge ===== | ||
| | process context | includes user context, kernel thread, work queue | | | process context | includes user context, kernel thread, work queue | | ||
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| | Tasklet | A dynamically-registered software interrupt, which is guaranteed to only run on one CPU at a time | | | Tasklet | A dynamically-registered software interrupt, which is guaranteed to only run on one CPU at a time | | ||
| | Timer | which is running at (or close to) a given time. When running, it is just like a tasklet (in fact, they are called from the TIMER_SOFTIRQ). | | | Timer | which is running at (or close to) a given time. When running, it is just like a tasklet (in fact, they are called from the TIMER_SOFTIRQ). | | ||
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mywiki/linux/linux_kernel_notes.1433757517.txt.gz · Last modified: (external edit)