From: Andrea Arcangeli <aarcange@redhat.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
tim.c.chen@intel.com, dave.hansen@intel.com,
andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
Shaohua Li <shli@kernel.org>, Rik van Riel <riel@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Vladimir Davydov <vdavydov@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out
Date: Tue, 13 Sep 2016 16:35:48 +0200 [thread overview]
Message-ID: <20160913143548.GP19048@redhat.com> (raw)
In-Reply-To: <87vay0ji3m.fsf@yhuang-mobile.sh.intel.com>
Hello,
On Tue, Sep 13, 2016 at 04:53:49PM +0800, Huang, Ying wrote:
> I am glad to discuss my final goal, that is, swapping out/in the full
> THP without splitting. Why I want to do that is copied as below,
I think that is a fine objective. It wasn't implemented initially just
to keep things simple.
Doing it will reduce swap fragmentation (provided we can find a
physically contiguous piece of to swapout the THP in the first place)
and it will make all other heuristics that tries to keep the swap
space contiguous less relevant and it should increase the swap
bandwidth significantly at least on spindle disks. I personally see it
as a positive that we relay less on those and the readhaead swapin.
> >> >> The disadvantage are:
> >> >>
> >> >> - Increase the memory pressure when swap in THP.
That is always true with THP enabled to always. It is the tradeoff. It
still cannot use more RAM than userland ever allocated in the vma as
virtual memory. If userland don't ever need such memory it can free it
by zapping the vma and the THP will be splitted. If the vma is zapped
while the THP is natively swapped out, the zapped portion of swap
space shall be released as well. So ultimately userland always
controls the cap on the max virtual memory (ram+swap) the kernel
decides to use with THP enabled to always.
> I think it is important to use 2M pages as much as possible to deal with
> the big memory problem. Do you agree?
I agree.
Thanks,
Andrea
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
tim.c.chen@intel.com, dave.hansen@intel.com,
andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
Shaohua Li <shli@kernel.org>, Rik van Riel <riel@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Vladimir Davydov <vdavydov@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out
Date: Tue, 13 Sep 2016 16:35:48 +0200 [thread overview]
Message-ID: <20160913143548.GP19048@redhat.com> (raw)
In-Reply-To: <87vay0ji3m.fsf@yhuang-mobile.sh.intel.com>
Hello,
On Tue, Sep 13, 2016 at 04:53:49PM +0800, Huang, Ying wrote:
> I am glad to discuss my final goal, that is, swapping out/in the full
> THP without splitting. Why I want to do that is copied as below,
I think that is a fine objective. It wasn't implemented initially just
to keep things simple.
Doing it will reduce swap fragmentation (provided we can find a
physically contiguous piece of to swapout the THP in the first place)
and it will make all other heuristics that tries to keep the swap
space contiguous less relevant and it should increase the swap
bandwidth significantly at least on spindle disks. I personally see it
as a positive that we relay less on those and the readhaead swapin.
> >> >> The disadvantage are:
> >> >>
> >> >> - Increase the memory pressure when swap in THP.
That is always true with THP enabled to always. It is the tradeoff. It
still cannot use more RAM than userland ever allocated in the vma as
virtual memory. If userland don't ever need such memory it can free it
by zapping the vma and the THP will be splitted. If the vma is zapped
while the THP is natively swapped out, the zapped portion of swap
space shall be released as well. So ultimately userland always
controls the cap on the max virtual memory (ram+swap) the kernel
decides to use with THP enabled to always.
> I think it is important to use 2M pages as much as possible to deal with
> the big memory problem. Do you agree?
I agree.
Thanks,
Andrea
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-09-13 14:35 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-07 16:45 [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out Huang, Ying
2016-09-07 16:45 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 01/10] mm, swap: Make swap cluster size same of THP size on x86_64 Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 5:45 ` Anshuman Khandual
2016-09-08 5:45 ` Anshuman Khandual
2016-09-08 18:07 ` Huang, Ying
2016-09-08 18:07 ` Huang, Ying
2016-09-19 17:09 ` Johannes Weiner
2016-09-19 17:09 ` Johannes Weiner
2016-09-20 2:01 ` Huang, Ying
2016-09-20 2:01 ` Huang, Ying
2016-09-22 19:25 ` Johannes Weiner
2016-09-22 19:25 ` Johannes Weiner
2016-09-23 8:47 ` Huang, Ying
2016-09-08 8:21 ` Anshuman Khandual
2016-09-08 8:21 ` Anshuman Khandual
2016-09-08 11:03 ` Kirill A. Shutemov
2016-09-08 11:03 ` Kirill A. Shutemov
2016-09-08 17:39 ` Huang, Ying
2016-09-08 17:39 ` Huang, Ying
2016-09-08 11:07 ` Kirill A. Shutemov
2016-09-08 11:07 ` Kirill A. Shutemov
2016-09-08 17:23 ` Huang, Ying
2016-09-08 17:23 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 02/10] mm, memcg: Add swap_cgroup_iter iterator Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 03/10] mm, memcg: Support to charge/uncharge multiple swap entries Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 5:46 ` Anshuman Khandual
2016-09-08 5:46 ` Anshuman Khandual
2016-09-08 8:28 ` Anshuman Khandual
2016-09-08 8:28 ` Anshuman Khandual
2016-09-08 18:15 ` Huang, Ying
2016-09-08 18:15 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 04/10] mm, THP, swap: Add swap cluster allocate/free functions Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 5:49 ` Anshuman Khandual
2016-09-08 5:49 ` Anshuman Khandual
2016-09-08 8:30 ` Anshuman Khandual
2016-09-08 8:30 ` Anshuman Khandual
2016-09-08 18:14 ` Huang, Ying
2016-09-08 18:14 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 05/10] mm, THP, swap: Add get_huge_swap_page() Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 11:13 ` Kirill A. Shutemov
2016-09-08 11:13 ` Kirill A. Shutemov
2016-09-08 17:22 ` Huang, Ying
2016-09-08 17:22 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 06/10] mm, THP, swap: Support to clear SWAP_HAS_CACHE for huge page Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 07/10] mm, THP, swap: Support to add/delete THP to/from swap cache Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 9:00 ` Anshuman Khandual
2016-09-08 9:00 ` Anshuman Khandual
2016-09-08 18:10 ` Huang, Ying
2016-09-08 18:10 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 08/10] mm, THP: Add can_split_huge_page() Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-08 11:17 ` Kirill A. Shutemov
2016-09-08 11:17 ` Kirill A. Shutemov
2016-09-08 17:02 ` Huang, Ying
2016-09-08 17:02 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 09/10] mm, THP, swap: Support to split THP in swap cache Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 10/10] mm, THP, swap: Delay splitting THP during swap out Huang, Ying
2016-09-07 16:46 ` Huang, Ying
2016-09-09 5:43 ` [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out Minchan Kim
2016-09-09 5:43 ` Minchan Kim
2016-09-09 15:53 ` Tim Chen
2016-09-09 15:53 ` Tim Chen
2016-09-09 20:35 ` Huang, Ying
2016-09-09 20:35 ` Huang, Ying
2016-09-13 6:13 ` Minchan Kim
2016-09-13 6:13 ` Minchan Kim
2016-09-13 6:40 ` Huang, Ying
2016-09-13 6:40 ` Huang, Ying
2016-09-13 7:05 ` Minchan Kim
2016-09-13 7:05 ` Minchan Kim
2016-09-13 8:53 ` Huang, Ying
2016-09-13 8:53 ` Huang, Ying
2016-09-13 9:16 ` Minchan Kim
2016-09-13 9:16 ` Minchan Kim
2016-09-13 23:52 ` Chen, Tim C
2016-09-13 23:52 ` Chen, Tim C
2016-09-19 7:11 ` Minchan Kim
2016-09-19 7:11 ` Minchan Kim
2016-09-19 15:59 ` Tim Chen
2016-09-19 15:59 ` Tim Chen
2016-09-18 1:53 ` Huang, Ying
2016-09-18 1:53 ` Huang, Ying
2016-09-19 7:08 ` Minchan Kim
2016-09-19 7:08 ` Minchan Kim
2016-09-20 2:54 ` Huang, Ying
2016-09-20 2:54 ` Huang, Ying
2016-09-20 5:06 ` Minchan Kim
2016-09-20 5:06 ` Minchan Kim
2016-09-20 5:28 ` Huang, Ying
2016-09-20 5:28 ` Huang, Ying
2016-09-13 14:35 ` Andrea Arcangeli [this message]
2016-09-13 14:35 ` Andrea Arcangeli
2016-09-19 17:33 ` Hugh Dickins
2016-09-19 17:33 ` Hugh Dickins
2016-09-22 22:56 ` Shaohua Li
2016-09-22 22:56 ` Shaohua Li
2016-09-22 23:49 ` Chen, Tim C
2016-09-22 23:49 ` Chen, Tim C
2016-09-22 23:53 ` Andi Kleen
2016-09-22 23:53 ` Andi Kleen
2016-09-23 0:38 ` Rik van Riel
2016-09-23 2:32 ` Huang, Ying
2016-09-23 2:32 ` Huang, Ying
2016-09-25 19:18 ` Shaohua Li
2016-09-25 19:18 ` Shaohua Li
2016-09-26 1:06 ` Minchan Kim
2016-09-26 1:06 ` Minchan Kim
2016-09-26 3:25 ` Huang, Ying
2016-09-26 3:25 ` Huang, Ying
2016-09-23 2:12 ` Huang, Ying
2016-09-23 2:12 ` Huang, Ying
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=20160913143548.GP19048@redhat.com \
--to=aarcange@redhat.com \
--cc=aaron.lu@intel.com \
--cc=akpm@linux-foundation.org \
--cc=andi.kleen@intel.com \
--cc=dave.hansen@intel.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=minchan@kernel.org \
--cc=riel@redhat.com \
--cc=shli@kernel.org \
--cc=tim.c.chen@intel.com \
--cc=vdavydov@virtuozzo.com \
--cc=ying.huang@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.