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From: Lev Olshvang <levonshe@yandex.com>
To: kernelnewbies <kernelnewbies@kernelnewbies.org>,
	linux-il <linux-il@cs.huji.ac.il>
Subject: What will happen on attempt to write to read-only page when CONFIG_MEM_SOFT_DIRTY is off ?
Date: Mon, 11 Mar 2019 10:27:44 +0300	[thread overview]
Message-ID: <21618991552289264@iva7-7c2970ec7645.qloud-c.yandex.net> (raw)

Hello all,
Please help me to clarify what will page fault handler do (if any)

File arch/x86/include/asm/pgtable_types.h have following comment for  2  PAGE_DIRTY_BITs

#define _PAGE_BIT_DIRTY		6	/* was written to (raised by CPU) */
_PAGE_BIT_SOFT_DIRTY	_PAGE_BIT_SOFTW3 /* software dirty tracking */

While documentation clearly explains that Page Fault handler sets second flag
https://www.kernel.org/doc/Documentation/vm/soft-dirty.txt

I do not have idea what will happen when tracking Soft Dirty flags is off, I suppose the answer is in mm/gup.c 
but I was not able to track it to page handler.

Thanks you all.
Lev.



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                 reply	other threads:[~2019-03-11  7:28 UTC|newest]

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