From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Daniel Gomez <da.gomez@samsung.com>,
"minchan@kernel.org" <minchan@kernel.org>,
"senozhatsky@chromium.org" <senozhatsky@chromium.org>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"djwong@kernel.org" <djwong@kernel.org>,
"hughd@google.com" <hughd@google.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"mcgrof@kernel.org" <mcgrof@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"gost.dev@samsung.com" <gost.dev@samsung.com>,
Pankaj Raghav <p.raghav@samsung.com>
Subject: Re: [PATCH 0/6] shmem: high order folios support in write path
Date: Fri, 15 Sep 2023 16:34:54 +0100 [thread overview]
Message-ID: <ZQR5nq7mKBJKEFHL@casper.infradead.org> (raw)
In-Reply-To: <b8f75b8e-77f5-4aa1-ce73-6c90f7d87d43@redhat.com>
On Fri, Sep 15, 2023 at 05:29:51PM +0200, David Hildenbrand wrote:
> On 15.09.23 11:51, Daniel Gomez wrote:
> > This series add support for high order folios in shmem write
> > path.
> > There are at least 2 cases/topics to handle that I'd appreciate
> > feedback.
> > 1. With the new strategy, you might end up with a folio order matching
> > HPAGE_PMD_ORDER. However, we won't respect the 'huge' flag anymore if
> > THP is enabled.
> > 2. When the above (1.) occurs, the code skips the huge path, so
> > xa_find with hindex is skipped.
>
> Similar to large anon folios (but different to large non-shmem folios in the
> pagecache), this can result in memory waste.
No, it can't. This patchset triggers only on write, not on read or page
fault, and it's conservative, so it will only allocate folios which are
entirely covered by the write. IOW this is memory we must allocate in
order to satisfy the write; we're just allocating it in larger chunks
when we can.
next prev parent reply other threads:[~2023-09-15 15:35 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230915095123eucas1p2c23d8a8d910f5a8e9fd077dd9579ad0a@eucas1p2.samsung.com>
2023-09-15 9:51 ` [PATCH 0/6] shmem: high order folios support in write path Daniel Gomez
[not found] ` <CGME20230915095124eucas1p1eb0e0ef883f6316cf14c349404a51150@eucas1p1.samsung.com>
2023-09-15 9:51 ` [PATCH 1/6] filemap: make the folio order calculation shareable Daniel Gomez
2023-09-15 13:40 ` Matthew Wilcox
2023-09-18 8:41 ` Daniel Gomez
2023-09-18 18:09 ` Luis Chamberlain
2023-09-18 18:24 ` Matthew Wilcox
2023-09-18 18:42 ` Luis Chamberlain
[not found] ` <CGME20230915095126eucas1p2cf75674dab8a81228f493a7200f4a1ba@eucas1p2.samsung.com>
2023-09-15 9:51 ` [PATCH 2/6] shmem: drop BLOCKS_PER_PAGE macro Daniel Gomez
[not found] ` <CGME20230915095128eucas1p2885c3add58d82413d9c1d17832d3d281@eucas1p2.samsung.com>
2023-09-15 9:51 ` [PATCH 3/6] shmem: account for large order folios Daniel Gomez
2023-09-15 12:14 ` Matthew Wilcox
2023-09-15 13:44 ` Matthew Wilcox
[not found] ` <CGME20230915095129eucas1p1383d75c6d62056afbb20b78a3ec15234@eucas1p1.samsung.com>
2023-09-15 9:51 ` [PATCH 4/6] shmem: add order parameter support to shmem_alloc_folio Daniel Gomez
2023-09-15 12:19 ` Matthew Wilcox
[not found] ` <CGME20230915095131eucas1p1010e364cd1c351e5b7379954bd237a3d@eucas1p1.samsung.com>
2023-09-15 9:51 ` [PATCH 5/6] shmem: add file length in shmem_get_folio path Daniel Gomez
2023-09-15 15:37 ` Matthew Wilcox
[not found] ` <CGME20230915095133eucas1p267bade2888b7fcd2e1ea8e13e21c495f@eucas1p2.samsung.com>
2023-09-15 9:51 ` [PATCH 6/6] shmem: add large folios support to the write path Daniel Gomez
2023-09-15 18:26 ` Yosry Ahmed
2023-09-18 8:00 ` Daniel Gomez
2023-09-18 18:55 ` Yosry Ahmed
2023-09-19 13:27 ` Daniel Gomez
2023-09-19 16:00 ` Yosry Ahmed
2023-09-19 21:46 ` Luis Chamberlain
2023-09-19 21:51 ` Yosry Ahmed
2023-09-15 15:29 ` [PATCH 0/6] shmem: high order folios support in " David Hildenbrand
2023-09-15 15:34 ` Matthew Wilcox [this message]
2023-09-15 15:36 ` David Hildenbrand
2023-09-15 15:40 ` Matthew Wilcox
2023-09-15 15:43 ` David Hildenbrand
2023-09-18 7:32 ` Daniel Gomez
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