From: David Laight <David.Laight@ACULAB.COM>
To: 'Kent Overstreet' <kent.overstreet@linux.dev>,
Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-bcachefs@vger.kernel.org" <linux-bcachefs@vger.kernel.org>,
Kent Overstreet <kent.overstreet@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Uladzislau Rezki <urezki@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: RE: [PATCH 07/32] mm: Bring back vmalloc_exec
Date: Wed, 10 May 2023 11:56:05 +0000 [thread overview]
Message-ID: <aa542818337b4157bfdcf262926b9fe3@AcuMS.aculab.com> (raw)
In-Reply-To: <ZFq7JhrhyrMTNfd/@moria.home.lan>
From: Kent Overstreet
> Sent: 09 May 2023 22:29
...
> The background is that bcachefs generates a per btree node unpack
> function, based on the packed format for that btree node, for unpacking
> keys within that node. The unpack function is only ~50 bytes, and for
> locality we want it to be located with the btree node's other in-memory
> lookup tables so they can be prefetched all at once.
Loading data into the d-cache isn't going to load code into
the i-cache.
Indeed you don't want to be mixing code and data in the same
cache line - because it just wastes space in the cache.
Looks to me like you could have a few different unpack
functions and pick the correct one based on the packed format.
Quite likely the code would be just as fast (if longer)
when you allow for parallel execution on modern cpu.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-05-10 11:56 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-09 16:56 [PATCH 00/32] bcachefs - a new COW filesystem Kent Overstreet
2023-05-09 16:56 ` [PATCH 07/32] mm: Bring back vmalloc_exec Kent Overstreet
2023-05-09 18:19 ` Lorenzo Stoakes
2023-05-09 20:15 ` Kent Overstreet
2023-05-09 20:46 ` Christoph Hellwig
2023-05-09 21:12 ` Lorenzo Stoakes
2023-05-09 21:29 ` Kent Overstreet
2023-05-10 6:48 ` Eric Biggers
2023-05-12 18:36 ` Kent Overstreet
2023-05-13 1:57 ` Eric Biggers
2023-05-13 19:28 ` Kent Overstreet
2023-05-14 5:45 ` Kent Overstreet
2023-05-14 18:43 ` Eric Biggers
2023-05-15 5:38 ` Kent Overstreet
2023-05-15 6:13 ` Eric Biggers
2023-05-15 6:18 ` Kent Overstreet
2023-05-15 7:13 ` Eric Biggers
2023-05-15 7:26 ` Kent Overstreet
2023-05-21 21:33 ` Eric Biggers
2023-05-21 22:04 ` Kent Overstreet
2023-05-15 10:29 ` David Laight
2023-05-10 11:56 ` David Laight [this message]
2023-05-09 21:43 ` Darrick J. Wong
2023-05-09 21:54 ` Kent Overstreet
2023-05-11 5:33 ` Theodore Ts'o
2023-05-11 5:44 ` Kent Overstreet
2023-05-13 13:25 ` Lorenzo Stoakes
2023-05-14 18:39 ` Christophe Leroy
2023-05-14 23:43 ` Kent Overstreet
2023-05-15 4:45 ` Christophe Leroy
2023-05-15 5:02 ` Kent Overstreet
2023-05-10 14:18 ` Christophe Leroy
2023-05-10 15:05 ` Johannes Thumshirn
2023-05-11 22:28 ` Kees Cook
2023-05-12 18:41 ` Kent Overstreet
2023-05-16 21:02 ` Kees Cook
2023-05-16 21:20 ` Kent Overstreet
2023-05-16 21:47 ` Matthew Wilcox
2023-05-16 21:57 ` Kent Overstreet
2023-05-17 5:28 ` Kent Overstreet
2023-05-17 14:04 ` Mike Rapoport
2023-05-17 14:18 ` Kent Overstreet
2023-05-17 15:44 ` Mike Rapoport
2023-05-17 15:59 ` Kent Overstreet
2023-06-17 4:13 ` Andy Lutomirski
2023-06-17 15:34 ` Kent Overstreet
2023-06-17 19:19 ` Andy Lutomirski
2023-06-17 20:08 ` Kent Overstreet
2023-06-17 20:35 ` Andy Lutomirski
2023-06-19 19:45 ` Kees Cook
2023-06-20 0:39 ` Kent Overstreet
2023-06-19 9:19 ` Mark Rutland
2023-06-19 10:47 ` Kent Overstreet
2023-06-19 12:47 ` Mark Rutland
2023-06-19 19:17 ` Kent Overstreet
2023-06-20 17:42 ` Andy Lutomirski
2023-06-20 18:08 ` Kent Overstreet
2023-06-20 18:15 ` Andy Lutomirski
2023-06-20 18:48 ` Dave Hansen
2023-06-20 20:18 ` Kent Overstreet
2023-06-20 20:42 ` Andy Lutomirski
2023-06-20 22:32 ` Andy Lutomirski
2023-06-20 22:43 ` Nadav Amit
2023-06-21 1:27 ` Andy Lutomirski
2023-06-15 20:41 ` [PATCH 00/32] bcachefs - a new COW filesystem Pavel Machek
2023-06-15 21:26 ` Kent Overstreet
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