From: Mike Kravetz <mike.kravetz@oracle.com>
To: malate_wangshu@hotmail.com
Cc: Linux Memory Management List <linux-mm@kvack.org>
Subject: [Bug 211287] New: Softdirty bit does not work with hugetlb
Date: Thu, 21 Jan 2021 16:58:29 -0800 [thread overview]
Message-ID: <999775bf-4204-2bec-7c3d-72d81b4fce30@oracle.com> (raw)
>> Start Bug Report <<
Bug ID: 211287
https://bugzilla.kernel.org/show_bug.cgi?id=211287
Summary: Softdirty bit does not work with hugetlb
When a memory region is mapped with huge pages, the softdirty bit is set only
right after the huge pages is mapped. After the memory mapping, if the
softdirty bit is cleared and the memory is written again, the softdirty bit is
not set when reading from the process's pagemap.
>> End Bug Report <<
I am not surprised with this reported bug. The page fault code diverges
pretty quickly for hugetlb pages. I have not looked closely at the details
of soft dirty, and do not immediately see where in the fault path for normal
pages it gets reset. But, I only took a quick glance.
I can work on adding support for hugetlb.
Can you provide some details about your use case?
--
Mike Kravetz
next reply other threads:[~2021-01-22 0:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 0:58 Mike Kravetz [this message]
2021-01-22 18:42 ` [Bug 211287] New: Softdirty bit does not work with hugetlb shu wang
2021-01-22 21:50 ` Mike Kravetz
2021-02-02 1:02 ` Mike Kravetz
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