[SOS] flag dirty dans la pagination

[Thomas Petazzoni]

Le Wed, 10 Dec 2008 20:38:08 +0100 (CET),
"anthoine.bourgeois" <anthoine.bourgeois at orange.fr> a écrit :

> La question:
> Le flag dirty d'une pte doit-il être positionné par l'OS
> ou est-il modifier par le processeur lors d'un accès en
> écriture sur cette page ?

C'est le processeur qui le fait. Documentation Intel, volume 3, section
3.6.4 :

«
Dirty (D) flag, bit 6

Indicates whether a page has been written to when set. (This flag is
not used in page-directory entries that point to page tables.) Memory
management soft- ware typically clears this flag when a page is
initially loaded into physical memory. The processor then sets this
flag the first time a page is accessed for a write operation. This flag
is “sticky,” meaning that once set, the processor does not implicitly
clear it. Only software can clear this flag. The dirty and accessed
flags are provided for use by memory management software to manage the
transfer of pages and page tables into and out of physical memory.
»

Thomas
-- 
Thomas Petazzoni                         http://thomas.enix.org
Promouvoir et défendre le Logiciel Libre http://www.april.org
Logiciels Libres à Toulouse              http://www.toulibre.org
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