lkml.org 
[lkml]   [2020]   [Nov]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [patch V3 05/37] asm-generic: Provide kmap_size.h
On Tue, Nov 3, 2020 at 10:27 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> kmap_types.h is a misnomer because the old atomic MAP based array does not
> exist anymore and the whole indirection of architectures including
> kmap_types.h is inconinstent and does not allow to provide guard page
> debugging for this misfeature.
>
> Add a common header file which defines the mapping stack size for all
> architectures. Will be used when converting architectures over to a
> generic kmap_local/atomic implementation.
>
> The array size is chosen with the following constraints in mind:
>
> - The deepest nest level in one context is 3 according to code
> inspection.
>
> - The worst case nesting for the upcoming reemptible version would be:
>
> 2 maps in task context and a fault inside
> 2 maps in the fault handler
> 3 maps in softirq
> 2 maps in interrupt
>
> So a total of 16 is sufficient and probably overestimated.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>

\
 
 \ /
  Last update: 2020-11-03 13:26    [W:0.050 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site