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From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Song Liu <songliubraving@fb.com>, Rik van Riel <riel@surriel.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Dave Chinner <dchinner@redhat.com>
Subject: Re: [PATCH 2/2] fs: Do not update nr_thps for mappings which support THPs
Date: Wed, 16 Sep 2020 12:46:49 +0100	[thread overview]
Message-ID: <20200916114649.GM5449@casper.infradead.org> (raw)
In-Reply-To: <20200916052126.GA12923@infradead.org>

On Wed, Sep 16, 2020 at 06:21:26AM +0100, Christoph Hellwig wrote:
> On Wed, Sep 16, 2020 at 04:27:17AM +0100, Matthew Wilcox (Oracle) wrote:
> > The nr_thps counter is to support THPs in the page cache when the
> > filesystem doesn't understand THPs.  Eventually it will be removed, but
> > we should still support filesystems which do not understand THPs yet.
> > Move the nr_thp manipulation functions to filemap.h since they're
> > page-cache specific.
> 
> Honestly I don't think we should support the read-only THP crap.  We
> should in fact never have merged that bandaid to start with given that
> you did good progress on the real thing.

I'd like to see the feature ripped out again, yes.  Once we have a few more
filesystems converted, I think that'll be a reasonable thing to do.

It was a good step along the way; Song fixed a number of problems,
and worked on other things that I never had to learn anything about
(like uprobes and khugepaged).  I wouldn't go so far as to say we should
never have merged it, but I think we can remove it in about six months.

      reply	other threads:[~2020-09-16 20:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-16  3:27 [PATCH 1/2] fs: Add a filesystem flag for THPs Matthew Wilcox (Oracle)
2020-09-16  3:27 ` [PATCH 2/2] fs: Do not update nr_thps for mappings which support THPs Matthew Wilcox (Oracle)
2020-09-16  5:21   ` Christoph Hellwig
2020-09-16 11:46     ` Matthew Wilcox [this message]

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