From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: peterx@redhat.com, Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>, Dave Jiang <dave.jiang@intel.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
linux-mm@kvack.org
Subject: [PATCH] mm: thp: fix soft dirty for migration when split
Date: Thu, 6 Dec 2018 16:46:04 +0800 [thread overview]
Message-ID: <20181206084604.17167-1-peterx@redhat.com> (raw)
When splitting a huge migrating PMD, we'll transfer the soft dirty bit
from the huge page to the small pages. However we're possibly using a
wrong data since when fetching the bit we're using pmd_soft_dirty()
upon a migration entry. Fix it up.
CC: Andrea Arcangeli <aarcange@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
CC: Matthew Wilcox <willy@infradead.org>
CC: Michal Hocko <mhocko@suse.com>
CC: Dave Jiang <dave.jiang@intel.com>
CC: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
CC: Souptick Joarder <jrdr.linux@gmail.com>
CC: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
CC: linux-mm@kvack.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
I noticed this during code reading. Only compile tested. I'm sending
a patch directly for review comments since it's relatively
straightforward and not easy to test. Please have a look, thanks.
---
mm/huge_memory.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f2d19e4fe854..fb0787c3dd3b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2161,7 +2161,10 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
SetPageDirty(page);
write = pmd_write(old_pmd);
young = pmd_young(old_pmd);
- soft_dirty = pmd_soft_dirty(old_pmd);
+ if (unlikely(pmd_migration))
+ soft_dirty = pmd_swp_soft_dirty(old_pmd);
+ else
+ soft_dirty = pmd_soft_dirty(old_pmd);
/*
* Withdraw the table only after we mark the pmd entry invalid.
--
2.17.1
next reply other threads:[~2018-12-06 8:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 8:46 Peter Xu [this message]
2018-12-07 3:34 ` [PATCH] mm: thp: fix soft dirty for migration when split Peter Xu
[not found] ` <CALYGNiMjWDL6XaOFgfrM1WR6_GnmxfLBXwJ=YYGVNfEKNX0MfQ@mail.gmail.com>
2018-12-11 4:48 ` Peter Xu
2018-12-11 13:12 ` Konstantin Khlebnikov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181206084604.17167-1-peterx@redhat.com \
--to=peterx@redhat.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=dave.jiang@intel.com \
--cc=jrdr.linux@gmail.com \
--cc=khlebnikov@yandex-team.ru \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).