From: "Christoph Lameter (Ampere)" <cl@gentwo.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>
Subject: Re: [PATCH] mm/slub: Make __ksize() faster
Date: Fri, 8 Mar 2024 09:12:06 -0800 (PST) [thread overview]
Message-ID: <9b609df3-b4af-e0fa-dcbe-1358cd317194@gentwo.org> (raw)
In-Reply-To: <ZetFrixmULTtjPCK@casper.infradead.org>
> On Fri, Mar 08, 2024 at 11:27:32AM -0500, Kent Overstreet wrote:
>> On Fri, Mar 08, 2024 at 02:58:48PM +0000, Matthew Wilcox wrote:
>>> There are potentiually better uses for those bits. We could turn
>>> folio_test_slab() into a PageType test, freeing up a page flag.
>>
>> They overlap _mapcount, did you figure out how to use that for a
>> PageType enum?
>
> In 2018 ... 6e292b9be7f4358985ce33ae1f59ab30a8c09e08
>
This seems to be 32 bit field. We could segment that into two unsigned
shorts. In fact any operation on a slab larger than 2xPAGE_SIZE is
directly turned into a page allocator call bypassing slub. So you only
need 0 ... 2 * PAGE_SIZE for the range of the int.
next prev parent reply other threads:[~2024-03-08 17:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-08 3:13 Kent Overstreet
2024-03-08 4:48 ` Matthew Wilcox
2024-03-08 5:16 ` Kent Overstreet
2024-03-08 14:58 ` Matthew Wilcox
2024-03-08 16:27 ` Kent Overstreet
2024-03-08 17:06 ` Matthew Wilcox
2024-03-08 17:12 ` Christoph Lameter (Ampere) [this message]
2024-03-08 18:26 ` Matthew Wilcox
2024-03-08 20:58 ` Kent Overstreet
2024-03-08 21:28 ` Christoph Lameter (Ampere)
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