From: Bob Liu <lliubbo@gmail.com>
To: Joonsoo Kim <js1304@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Russell King <rmk+kernel@arm.linux.org.uk>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kexec@lists.infradead.org
Subject: Re: [RFC PATCH 0/8] remove vm_struct list management
Date: Fri, 7 Dec 2012 11:37:30 +0800 [thread overview]
Message-ID: <CAA_GA1fiQfOqApE05oh=2Wr-GejbHtOd4o7sqcGdQFH6cxWPpQ@mail.gmail.com> (raw)
In-Reply-To: <1354810175-4338-1-git-send-email-js1304@gmail.com>
Hi Joonsoo,
On Fri, Dec 7, 2012 at 12:09 AM, Joonsoo Kim <js1304@gmail.com> wrote:
> This patchset remove vm_struct list management after initializing vmalloc.
> Adding and removing an entry to vmlist is linear time complexity, so
> it is inefficient. If we maintain this list, overall time complexity of
> adding and removing area to vmalloc space is O(N), although we use
> rbtree for finding vacant place and it's time complexity is just O(logN).
>
> And vmlist and vmlist_lock is used many places of outside of vmalloc.c.
> It is preferable that we hide this raw data structure and provide
> well-defined function for supporting them, because it makes that they
> cannot mistake when manipulating theses structure and it makes us easily
> maintain vmalloc layer.
>
> I'm not sure that "7/8: makes vmlist only for kexec" is fine.
> Because it is related to userspace program.
> As far as I know, makedumpfile use kexec's output information and it only
> need first address of vmalloc layer. So my implementation reflect this
> fact, but I'm not sure. And now, I don't fully test this patchset.
> Basic operation work well, but I don't test kexec. So I send this
> patchset with 'RFC'.
>
> Please let me know what I am missing.
>
Nice work!
I also thought about this several weeks ago but I think the efficiency
may be a problem.
As you know two locks(vmap_area_lock and vmlist_lock) are used
currently so that some
work may be done in parallel(not proved).
If removed vmlist, i'm afraid vmap_area_lock will become a bottleneck
which will reduce the efficiency.
> This series based on v3.7-rc7 and on top of submitted patchset for ARM.
> 'introduce static_vm for ARM-specific static mapped area'
> https://lkml.org/lkml/2012/11/27/356
> But, running properly on x86 without ARM patchset.
>
> Joonsoo Kim (8):
> mm, vmalloc: change iterating a vmlist to find_vm_area()
> mm, vmalloc: move get_vmalloc_info() to vmalloc.c
> mm, vmalloc: protect va->vm by vmap_area_lock
> mm, vmalloc: iterate vmap_area_list, instead of vmlist in
> vread/vwrite()
> mm, vmalloc: iterate vmap_area_list in get_vmalloc_info()
> mm, vmalloc: iterate vmap_area_list, instead of vmlist, in
> vmallocinfo()
> mm, vmalloc: makes vmlist only for kexec
> mm, vmalloc: remove list management operation after initializing
> vmalloc
>
> arch/tile/mm/pgtable.c | 7 +-
> arch/unicore32/mm/ioremap.c | 17 +--
> arch/x86/mm/ioremap.c | 7 +-
> fs/proc/Makefile | 2 +-
> fs/proc/internal.h | 18 ---
> fs/proc/meminfo.c | 1 +
> fs/proc/mmu.c | 60 ----------
> include/linux/vmalloc.h | 19 +++-
> mm/vmalloc.c | 258 +++++++++++++++++++++++++++++--------------
> 9 files changed, 204 insertions(+), 185 deletions(-)
> delete mode 100644 fs/proc/mmu.c
>
> --
> 1.7.9.5
>
--
Regards,
--Bob
next prev parent reply other threads:[~2012-12-07 3:37 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-06 16:09 [RFC PATCH 0/8] remove vm_struct list management Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 1/8] mm, vmalloc: change iterating a vmlist to find_vm_area() Joonsoo Kim
2012-12-07 7:44 ` Pekka Enberg
2012-12-07 8:15 ` Bob Liu
2012-12-07 13:40 ` JoonSoo Kim
2012-12-10 5:20 ` guanxuetao
2012-12-10 15:13 ` Chris Metcalf
2013-01-24 15:50 ` Ingo Molnar
2012-12-06 16:09 ` [RFC PATCH 2/8] mm, vmalloc: move get_vmalloc_info() to vmalloc.c Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 3/8] mm, vmalloc: protect va->vm by vmap_area_lock Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 4/8] mm, vmalloc: iterate vmap_area_list, instead of vmlist in vread/vwrite() Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 5/8] mm, vmalloc: iterate vmap_area_list in get_vmalloc_info() Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 6/8] mm, vmalloc: iterate vmap_area_list, instead of vmlist, in vmallocinfo() Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 7/8] mm, vmalloc: makes vmlist only for kexec Joonsoo Kim
2012-12-06 16:09 ` [RFC PATCH 8/8] mm, vmalloc: remove list management operation after initializing vmalloc Joonsoo Kim
2012-12-06 22:45 ` [RFC PATCH 0/8] remove vm_struct list management Andrew Morton
2012-12-07 13:05 ` JoonSoo Kim
2012-12-06 22:50 ` Andrew Morton
2012-12-07 13:16 ` JoonSoo Kim
2012-12-07 14:59 ` Vivek Goyal
2012-12-10 14:40 ` JoonSoo Kim
2012-12-11 14:41 ` Dave Anderson
2012-12-11 21:48 ` Vivek Goyal
2012-12-11 22:17 ` Dave Anderson
2012-12-12 5:56 ` Atsushi Kumagai
2012-12-12 14:10 ` JoonSoo Kim
2012-12-07 3:37 ` Bob Liu [this message]
2012-12-07 13:35 ` JoonSoo Kim
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='CAA_GA1fiQfOqApE05oh=2Wr-GejbHtOd4o7sqcGdQFH6cxWPpQ@mail.gmail.com' \
--to=lliubbo@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=js1304@gmail.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=rmk+kernel@arm.linux.org.uk \
/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).