Re: [PATCH v4 0/7] Split a folio to any lower order folios

From: David Hildenbrand <david@redhat.com>
To: Zi Yan <ziy@nvidia.com>,
	"Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>,
	linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Yang Shi" <shy828301@gmail.com>, "Yu Zhao" <yuzhao@google.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	"Ryan Roberts" <ryan.roberts@arm.com>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Roman Gushchin" <roman.gushchin@linux.dev>,
	"Zach O'Keefe" <zokeefe@google.com>,
	"Hugh Dickins" <hughd@google.com>,
	"Mcgrof Chamberlain" <mcgrof@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v4 0/7] Split a folio to any lower order folios
Date: Tue, 13 Feb 2024 23:21:48 +0100	[thread overview]
Message-ID: <659e1abb-40d0-42ba-ba0a-8256d7eb1c5a@redhat.com> (raw)
In-Reply-To: <20240213215520.1048625-1-zi.yan@sent.com>

On 13.02.24 22:55, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
> 
> Hi all,
> 
> File folio supports any order and multi-size THP is upstreamed[1], so both
> file and anonymous folios can be >0 order. Currently, split_huge_page()
> only splits a huge page to order-0 pages, but splitting to orders higher than
> 0 is going to better utilize large folios. In addition, Large Block
> Sizes in XFS support would benefit from it[2]. This patchset adds support for
> splitting a large folio to any lower order folios and uses it during file
> folio truncate operations.
> 
> For Patch 6, Hugh did not like my approach to minimize the number of
> folios for truncate[3]. I would like to get more feedback, especially
> from FS people, on it to decide whether to keep it or not.

I'm curious, would it make sense to exclude the "more" controversial 
parts (i.e., patch #6) for now, and focus on the XFS use case only?

-- 
Cheers,

David / dhildenb