From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: dave.hansen@intel.com
Cc: bhe@redhat.com, LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
pagupta@redhat.com,
Linux Memory Management List <linux-mm@kvack.org>,
kirill.shutemov@linux.intel.com
Subject: Re: [PATCH v5 4/4] mm/sparse: Optimize memmap allocation during sparse_init()
Date: Fri, 29 Jun 2018 13:48:06 -0400 [thread overview]
Message-ID: <CAGM2rebsL_fS8XKRvN34NWiFN3Hh63ZOD8jDj8qeSOUPXcZ2fA@mail.gmail.com> (raw)
In-Reply-To: <cb67381c-078c-62e6-e4c0-9ecf3de9e84d@intel.com>
> > + * increase 'nr_consumed_maps' whether its allocation of memmap
> > + * or usemap failed or not, so that after we handle the i-th
> > + * memory section, can get memmap and usemap of (i+1)-th section
> > + * correctly. */
>
> This makes no sense to me. Why are we incrementing 'nr_consumed_maps'
> when we do not consume one?
>
> You say that we increment it so that things will work, but not how or
> why it makes things work. I'm confused.
Hi Dave,
nr_consumed_maps is a local counter. map_map contains struct pages for
each section. In order to assign them to correct sections this local
counter must be incremented even when some parts of map_map are empty.
Here is example:
Node1:
map_map[0] -> Struct pages ...
map_map[1] -> NULL
Node2:
map_map[2] -> Struct pages ...
We always want to configure section from Node2 with struct pages from
Node2. Even, if there are holes in-between. The same with usemap.
Pavel
next prev parent reply other threads:[~2018-06-29 17:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-27 1:31 [PATCH v5 0/4] mm/sparse: Optimize memmap allocation during sparse_init() Baoquan He
2018-06-27 1:31 ` [PATCH v5 1/4] mm/sparse: Add a static variable nr_present_sections Baoquan He
2018-06-28 3:10 ` Pavel Tatashin
2018-06-27 1:31 ` [PATCH v5 2/4] mm/sparsemem: Defer the ms->section_mem_map clearing Baoquan He
2018-06-27 9:54 ` Oscar Salvador
2018-06-27 22:59 ` Baoquan He
2018-06-28 3:11 ` Pavel Tatashin
2018-06-27 1:31 ` [PATCH v5 3/4] mm/sparse: Add a new parameter 'data_unit_size' for alloc_usemap_and_memmap Baoquan He
2018-06-28 3:14 ` Pavel Tatashin
2018-06-28 6:57 ` Baoquan He
2018-06-27 1:31 ` [PATCH v5 4/4] mm/sparse: Optimize memmap allocation during sparse_init() Baoquan He
2018-06-28 3:19 ` Pavel Tatashin
2018-06-28 6:39 ` Baoquan He
2018-06-29 17:16 ` Dave Hansen
2018-06-29 17:48 ` Pavel Tatashin [this message]
2018-06-29 17:52 ` Dave Hansen
2018-06-29 18:01 ` Pavel Tatashin
2018-06-29 18:56 ` Dave Hansen
2018-06-29 18:59 ` Pavel Tatashin
2018-06-27 1:47 ` [PATCH v5 0/4] " Baoquan He
2018-06-27 17:47 ` Pavel Tatashin
2018-06-27 23:39 ` Baoquan He
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=CAGM2rebsL_fS8XKRvN34NWiFN3Hh63ZOD8jDj8qeSOUPXcZ2fA@mail.gmail.com \
--to=pasha.tatashin@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=dave.hansen@intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=pagupta@redhat.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).