Re: [PATCH RFC 00/15] decouple pagefault_disable() from preempt_disable()
From: David Hildenbrand <hidden>
Date: 2015-05-07 06:23:59
Also in:
linux-mm, lkml
From: David Hildenbrand <hidden>
Date: 2015-05-07 06:23:59
Also in:
linux-mm, lkml
quoted
This series therefore does 2 things: 1. Decouple pagefault_disable() from preempt_enable() ... 2. Reenable might_sleep() checks for might_fault()All seems sensible to me. pagefault_disabled has to go into the task_struct (rather than being per-cpu) because pagefault_disabled_inc() doesn't disable preemption, yes?
Right, we can now get scheduled while in pagefault_disable() (if preemption hasn't been disabled manually). So we have to store it per task/thread not per cpu. Actually even the preempt disable counter is only per-cpu for x86 and lives in thread_info for all other archs (which is also not 100% clean but doesn't matter at that point). I had that pagefault disable counter in thread_info before, but that required messing with asm-offsets of some arch (I had a proper version but this one feels cleaner). Thanks for having a look! David