Hi, While studying the follow_page() function (the version of the function that is in place since 2.4.4, i.e. with the write argument), I noticed, that for an address that should be written to (i.e. write != 0), the function checks not only the writeable flag (with pte_write()), but also the dirty flag (with pte_dirty()) of the page containing this address. From what I thought to understand from general paging theory, the dirty flag of a page is set, when its content in physical memory differs from its backing on the permanent storage system (file or swap space). Based on this understanding I do not understand why it is necessary to check the dirty flag, in order to ensure that a page is writable - what am I missing here? Thanks in advance for any answers with best regards Martin Maletinsky P.S. Pls. put me on cc: in your reply, since I am not on the mailing list. -- Supercomputing System AG email: maletinsky@scs.ch Martin Maletinsky phone: +41 (0)1 445 16 05 Technoparkstrasse 1 fax: +41 (0)1 445 16 10 CH-8005 Zurich -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
