From: Luis Chamberlain <mcgrof@kernel.org>
To: David Hildenbrand <david@redhat.com>, Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Christoph Lameter <christoph@lameter.com>,
Christoph Hellwig <hch@lst.de>,
Dave Chinner <david@fromorbit.com>,
Daniel Gomez <da.gomez@samsung.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hughd@google.com" <hughd@google.com>,
"ioworker0@gmail.com" <ioworker0@gmail.com>,
"wangkefeng.wang@huawei.com" <wangkefeng.wang@huawei.com>,
"ying.huang@intel.com" <ying.huang@intel.com>,
"21cnbao@gmail.com" <21cnbao@gmail.com>,
"ryan.roberts@arm.com" <ryan.roberts@arm.com>,
"shy828301@gmail.com" <shy828301@gmail.com>,
"ziy@nvidia.com" <ziy@nvidia.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 0/8] add mTHP support for anonymous shmem
Date: Fri, 10 May 2024 11:53:51 -0700 [thread overview]
Message-ID: <Zj5tP7k1muaCDtO_@bombadil.infradead.org> (raw)
In-Reply-To: <23ea6dbd-1d4e-4aeb-900b-646db880cfb6@redhat.com>
On Thu, May 09, 2024 at 07:48:46PM +0200, David Hildenbrand wrote:
> On 08.05.24 21:23, Luis Chamberlain wrote:
> > From my perspective the more shared code the better, and the more shared
> > paths the better. There is a chance to help test swap with large folios
> > instead of splitting the folios for swap, and that would could be done
> > first with tmpfs. I have not evaluated the difference in testing or how
> > we could get the most of shared code if we take a mTHP approach or the
> > iomap approach for tmpfs, that should be considered.
>
> I don't have a clear picture yet of what might be best for ordinary shmem
> (IOW, not MAP_SHARED|MAP_PRIVATE), and I'm afraid there is no easy answer.
OK so it sounds like the different options needs to be thought out and
reviewed.
> As long as we don't end up wasting memory, it's not obviously bad.
Sure.
> But some
> things might be tricky (see my example about large folios stranding in shmem
> and never being able to be really reclaimed+reused for better purposes)
Where is that stated BTW? Could that be resolved?
> I'll note that mTHP really is just (supposed to be) a user interface to
> enable the various folio sizes (well, and to expose better per-size stats),
> not more.
Sure but given filesystems using large folios don't have silly APIs for
using which large folios to enable, it just seems odd for tmpfs to take
a different approach.
> From that point of view, it's just a filter. Enable all, and you get the
> same behavior as you likely would in the pagecache mode.
Which begs the quesiton, *why* have an API to just constrain to certain
large folios, which diverges from what filesystems are doing with large
folios?
> > Are there other things to consider? Does this require some dialog at
> > LSFMM?
>
> As raised in my reply to Daniel, I'll be at LSF/MM and happy to discuss. I'm
> also not a SHMEM expert, so I'm hoping at some point we'd get feedback from
> Hugh.
Hugh, will you be at LSFMM?
Luis
prev parent reply other threads:[~2024-05-10 18:54 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 8:46 [PATCH 0/8] add mTHP support for anonymous shmem Baolin Wang
2024-05-06 8:46 ` [PATCH 1/8] mm: move highest_order() and next_order() out of the THP config Baolin Wang
2024-05-07 10:21 ` Ryan Roberts
2024-05-08 2:13 ` Baolin Wang
2024-05-08 9:06 ` Ryan Roberts
2024-05-08 9:40 ` Baolin Wang
2024-05-06 8:46 ` [PATCH 2/8] mm: memory: extend finish_fault() to support large folio Baolin Wang
2024-05-07 10:37 ` Ryan Roberts
2024-05-08 3:44 ` Baolin Wang
2024-05-08 7:15 ` David Hildenbrand
2024-05-08 9:06 ` Baolin Wang
2024-05-08 8:53 ` Ryan Roberts
2024-05-08 9:31 ` Baolin Wang
2024-05-08 10:47 ` Ryan Roberts
2024-05-09 1:10 ` Baolin Wang
2024-05-06 8:46 ` [PATCH 3/8] mm: shmem: add an 'order' parameter for shmem_alloc_hugefolio() Baolin Wang
2024-05-06 8:46 ` [PATCH 4/8] mm: shmem: add THP validation for PMD-mapped THP related statistics Baolin Wang
2024-05-06 8:46 ` [PATCH 5/8] mm: shmem: add multi-size THP sysfs interface for anonymous shmem Baolin Wang
2024-05-07 10:52 ` Ryan Roberts
2024-05-08 4:45 ` Baolin Wang
2024-05-08 7:08 ` David Hildenbrand
2024-05-08 7:12 ` David Hildenbrand
2024-05-08 9:02 ` Ryan Roberts
2024-05-08 9:56 ` Baolin Wang
2024-05-08 10:48 ` Ryan Roberts
2024-05-08 12:02 ` David Hildenbrand
2024-05-08 12:10 ` David Hildenbrand
2024-05-08 12:43 ` Ryan Roberts
2024-05-08 12:44 ` Ryan Roberts
2024-05-08 12:45 ` David Hildenbrand
2024-05-08 12:54 ` Ryan Roberts
2024-05-08 13:07 ` David Hildenbrand
2024-05-08 13:44 ` Ryan Roberts
2024-05-06 8:46 ` [PATCH 6/8] mm: shmem: add mTHP support " Baolin Wang
2024-05-07 10:46 ` kernel test robot
2024-05-08 6:03 ` Baolin Wang
2024-05-06 8:46 ` [PATCH 7/8] mm: shmem: add mTHP size alignment in shmem_get_unmapped_area Baolin Wang
2024-05-06 8:46 ` [PATCH 8/8] mm: shmem: add mTHP counters for anonymous shmem Baolin Wang
2024-05-06 10:54 ` [PATCH 0/8] add mTHP support " Lance Yang
2024-05-07 1:47 ` Baolin Wang
2024-05-07 6:50 ` Lance Yang
2024-05-07 10:20 ` Ryan Roberts
2024-05-08 5:45 ` Baolin Wang
[not found] ` <CGME20240508113934eucas1p13a3972f3f9955365f40155e084a7c7d5@eucas1p1.samsung.com>
2024-05-08 11:39 ` Daniel Gomez
2024-05-08 11:58 ` David Hildenbrand
2024-05-08 14:28 ` Daniel Gomez
2024-05-08 17:03 ` David Hildenbrand
2024-05-09 19:18 ` Daniel Gomez
2024-05-09 3:08 ` Baolin Wang
2024-05-08 19:23 ` Luis Chamberlain
2024-05-09 17:48 ` David Hildenbrand
2024-05-10 18:53 ` Luis Chamberlain [this message]
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=Zj5tP7k1muaCDtO_@bombadil.infradead.org \
--to=mcgrof@kernel.org \
--cc=21cnbao@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=christoph@lameter.com \
--cc=da.gomez@samsung.com \
--cc=david@fromorbit.com \
--cc=david@redhat.com \
--cc=hch@lst.de \
--cc=hughd@google.com \
--cc=ioworker0@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ryan.roberts@arm.com \
--cc=shy828301@gmail.com \
--cc=wangkefeng.wang@huawei.com \
--cc=willy@infradead.org \
--cc=ying.huang@intel.com \
--cc=ziy@nvidia.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 read-only IMAP folder(s) and NNTP newsgroup(s).