From: Baoquan He <bhe@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>, Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH 3/3] mm/sparsemem: avoid memmap overwrite for non-SPARSEMEM_VMEMMAP
Date: Fri, 7 Feb 2020 11:50:23 +0800 [thread overview]
Message-ID: <20200207035023.GT8965@MiWiFi-R3L-srv> (raw)
In-Reply-To: <CAPcyv4hLW5Ww1Bo0MmNi8fzUNQEvudtWpGOK23MWaiqQ+MemfA@mail.gmail.com>
On 02/06/20 at 06:06pm, Dan Williams wrote:
> On Thu, Feb 6, 2020 at 3:17 PM Wei Yang <richardw.yang@linux.intel.com> wrote:
> >
> > In case of SPARSEMEM, populate_section_memmap() would allocate memmap
> > for the whole section, even we just want a sub-section. This would lead
> > to memmap overwrite if we a sub-section to an already populated section.
> >
> > Just return the populated memmap for non-SPARSEMEM_VMEMMAP case.
> >
> > Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> > CC: Dan Williams <dan.j.williams@intel.com>
> > ---
> > mm/sparse.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/mm/sparse.c b/mm/sparse.c
> > index 56816f653588..c75ca40db513 100644
> > --- a/mm/sparse.c
> > +++ b/mm/sparse.c
> > @@ -836,6 +836,16 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
> > if (nr_pages < PAGES_PER_SECTION && early_section(ms))
> > return pfn_to_page(pfn);
> >
> > + /*
> > + * If it is not SPARSEMEM_VMEMMAP, we always populate memmap for the
> > + * whole section, even for a sub-section.
> > + *
> > + * Return its memmap if already populated to avoid memmap overwrite.
> > + */
> > + if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
> > + valid_section(ms))
> > + return __section_mem_map_addr(ms);
>
> Again, is check_pfn_span() failing to prevent this path?
The answer should be yes, this patch is not needed.
>
next prev parent reply other threads:[~2020-02-07 3:50 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 23:16 [PATCH 0/3] Fixes "mm/sparsemem: support sub-section hotplug" Wei Yang
2020-02-06 23:16 ` [PATCH 1/3] mm/sparsemem: adjust memmap only for SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:00 ` Dan Williams
2020-02-07 11:06 ` Wei Yang
2020-02-06 23:16 ` [PATCH 2/3] mm/sparsemem: get physical address to page struct instead of virtual address to pfn Wei Yang
2020-02-07 2:19 ` Dan Williams
2020-02-07 3:10 ` Baoquan He
2020-02-07 3:21 ` Dan Williams
2020-02-07 3:36 ` Baoquan He
2020-02-07 4:05 ` Dan Williams
2020-02-07 11:13 ` Wei Yang
2020-02-07 12:14 ` Wei Yang
2020-02-07 16:44 ` Dan Williams
2020-02-07 10:51 ` Wei Yang
2020-02-07 11:26 ` Wei Yang
2020-02-09 13:50 ` Baoquan He
2020-02-09 14:14 ` David Hildenbrand
2020-02-10 0:36 ` Wei Yang
2020-02-07 4:11 ` Baoquan He
2020-02-07 10:53 ` Wei Yang
2020-02-06 23:16 ` [PATCH 3/3] mm/sparsemem: avoid memmap overwrite for non-SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:06 ` Dan Williams
2020-02-07 3:50 ` Baoquan He [this message]
2020-02-07 11:02 ` Wei Yang
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=20200207035023.GT8965@MiWiFi-R3L-srv \
--to=bhe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=osalvador@suse.de \
--cc=richardw.yang@linux.intel.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).