From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Vineet Gupta <vgupta@synopsys.com>,
Russell King <linux@armlinux.org.uk>,
Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Ralf Baechle <ralf@linux-mips.org>,
"David S. Miller" <davem@davemloft.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm, thp: Do not loose dirty bit in __split_huge_pmd_locked()
Date: Wed, 14 Jun 2017 20:58:45 +0530 [thread overview]
Message-ID: <4f87514b-e00e-065b-aa04-802a3302aa1d@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170614135143.25068-4-kirill.shutemov@linux.intel.com>
On Wednesday 14 June 2017 07:21 PM, Kirill A. Shutemov wrote:
> Until pmdp_invalidate() pmd entry is present and CPU can update it,
> setting dirty. Currently, we tranfer dirty bit to page too early and
> there is window when we can miss dirty bit.
>
> Let's call SetPageDirty() after pmdp_invalidate().
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> mm/huge_memory.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index a84909cf20d3..c4ee5c890910 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1928,7 +1928,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
> struct page *page;
> pgtable_t pgtable;
> pmd_t _pmd;
> - bool young, write, dirty, soft_dirty;
> + bool young, write, soft_dirty;
> unsigned long addr;
> int i;
>
> @@ -1965,7 +1965,6 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
> page_ref_add(page, HPAGE_PMD_NR - 1);
> write = pmd_write(*pmd);
> young = pmd_young(*pmd);
> - dirty = pmd_dirty(*pmd);
> soft_dirty = pmd_soft_dirty(*pmd);
>
> pmdp_huge_split_prepare(vma, haddr, pmd);
> @@ -1995,8 +1994,6 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
> if (soft_dirty)
> entry = pte_mksoft_dirty(entry);
> }
> - if (dirty)
> - SetPageDirty(page + i);
> pte = pte_offset_map(&_pmd, addr);
> BUG_ON(!pte_none(*pte));
> set_pte_at(mm, addr, pte, entry);
> @@ -2046,6 +2043,14 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
> * pmd_populate.
> */
> pmdp_invalidate(vma, haddr, pmd);
> +
> + /*
> + * Transfer dirty bit to page after pmd invalidated, so CPU would not
> + * be able to set it under us.
> + */
> + if (pmd_dirty(*pmd))
> + SetPageDirty(page);
> +
> pmd_populate(mm, pmd, pgtable);
>
you fixed dirty bit loosing i discussed in my previous mail here.
thanks
-aneesh
next prev parent reply other threads:[~2017-06-14 15:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-14 13:51 [HELP-NEEDED, PATCH 0/3] Do not loose dirty bit on THP pages Kirill A. Shutemov
2017-06-14 13:51 ` [PATCH 1/3] x86/mm: Provide pmdp_mknotpresent() helper Kirill A. Shutemov
2017-06-14 16:09 ` Andrea Arcangeli
2017-06-15 4:43 ` kbuild test robot
2017-06-14 13:51 ` [PATCH 2/3] mm: Do not loose dirty and access bits in pmdp_invalidate() Kirill A. Shutemov
2017-06-15 8:48 ` kbuild test robot
2017-06-14 13:51 ` [PATCH 3/3] mm, thp: Do not loose dirty bit in __split_huge_pmd_locked() Kirill A. Shutemov
2017-06-14 14:18 ` Martin Schwidefsky
2017-06-14 15:31 ` Andrea Arcangeli
2017-06-15 8:46 ` Kirill A. Shutemov
2017-06-14 15:28 ` Aneesh Kumar K.V [this message]
2017-06-14 14:06 ` [HELP-NEEDED, PATCH 0/3] Do not loose dirty bit on THP pages Martin Schwidefsky
2017-06-14 15:25 ` Aneesh Kumar K.V
2017-06-14 16:55 ` Will Deacon
2017-06-14 17:00 ` Vlastimil Babka
2017-06-15 1:36 ` Aneesh Kumar K.V
2017-06-15 1:05 ` Aneesh Kumar K.V
2017-06-15 2:50 ` Aneesh Kumar K.V
2017-06-15 8:48 ` Kirill A. Shutemov
2017-06-15 9:36 ` Aneesh Kumar K.V
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=4f87514b-e00e-065b-aa04-802a3302aa1d@linux.vnet.ibm.com \
--to=aneesh.kumar@linux.vnet.ibm.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=catalin.marinas@arm.com \
--cc=davem@davemloft.net \
--cc=heiko.carstens@de.ibm.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux@armlinux.org.uk \
--cc=ralf@linux-mips.org \
--cc=schwidefsky@de.ibm.com \
--cc=vbabka@suse.cz \
--cc=vgupta@synopsys.com \
--cc=will.deacon@arm.com \
/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).