From: Matthew Wilcox <willy@infradead.org>
To: Hannes Reinecke <hare@suse.de>
Cc: Pankaj Raghav <p.raghav@samsung.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
mcgrof@kernel.org
Subject: Re: [PATCH] mm/filemap: allocate folios according to the blocksize
Date: Sun, 16 Apr 2023 05:00:56 +0100 [thread overview]
Message-ID: <ZDty+PQfHkrGBojn@casper.infradead.org> (raw)
In-Reply-To: <20230414134908.103932-1-hare@suse.de>
On Fri, Apr 14, 2023 at 03:49:08PM +0200, Hannes Reinecke wrote:
> @@ -3607,14 +3611,16 @@ static struct folio *do_read_cache_folio(struct address_space *mapping,
> pgoff_t index, filler_t filler, struct file *file, gfp_t gfp)
> {
> struct folio *folio;
> - int err;
> + int err, order = 0;
>
> + if (mapping->host->i_blkbits > PAGE_SHIFT)
> + order = mapping->host->i_blkbits - PAGE_SHIFT;
This pattern comes up a few times. What I did in a patch I wrote back
in December 2020 and never submitted (!) was this:
@@ -198,9 +198,15 @@ enum mapping_flags {
AS_EXITING = 4, /* final truncate in progress */
/* writeback related tags are not used */
AS_NO_WRITEBACK_TAGS = 5,
- AS_LARGE_FOLIO_SUPPORT = 6,
+ AS_FOLIO_ORDER_MIN = 8,
+ AS_FOLIO_ORDER_MAX = 13,
+ /* 8-17 are used for FOLIO_ORDER */
};
+#define AS_FOLIO_ORDER_MIN_MASK 0x00001f00
+#define AS_FOLIO_ORDER_MAX_MASK 0x0002e000
+#define AS_FOLIO_ORDER_MASK (AS_FOLIO_ORDER_MIN_MASK | AS_FOLIO_ORDER_MAX_MASK)
...
+static inline unsigned mapping_min_folio_order(struct address_space *mapping)
+{
+ return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN;
+}
(do we really need 5 bits for each, or can we get by with eg 3 or 4 bits?)
Anyway, the point is that we could set this quite early in the creation
of the mapping, and eliminate the conditional setting of order.
next prev parent reply other threads:[~2023-04-16 4:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230414134914eucas1p1f0b08409dce8bc946057d0a4fa7f1601@eucas1p1.samsung.com>
2023-04-14 13:49 ` [PATCH] mm/filemap: allocate folios according to the blocksize Hannes Reinecke
2023-04-14 13:56 ` Matthew Wilcox
2023-04-16 4:00 ` Matthew Wilcox [this message]
2023-04-17 2:18 ` kernel test robot
2023-04-17 4:10 ` Matthew Wilcox
2023-04-17 4:36 ` Christoph Hellwig
2023-04-17 6:08 ` Hannes Reinecke
2023-04-17 6:27 ` Christoph Hellwig
2023-04-17 6:30 ` Hannes Reinecke
2023-04-20 12:05 ` Pankaj Raghav
2023-04-20 12:19 ` Hannes Reinecke
2023-04-20 12:28 ` Pankaj Raghav
2023-04-20 15:03 ` Darrick J. Wong
2023-04-22 0:14 ` Dave Chinner
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