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From: "Christoph Lameter (Ampere)" <cl@linux.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
	Pekka Enberg <penberg@kernel.org>,
	 David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	 "Liam R. Howlett" <Liam.Howlett@oracle.com>,
	 Andrew Morton <akpm@linux-foundation.org>,
	 Roman Gushchin <roman.gushchin@linux.dev>,
	 Hyeonggon Yoo <42.hyeyoo@gmail.com>,
	 Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	 Dmitry Vyukov <dvyukov@google.com>,
	linux-mm@kvack.org,  linux-kernel@vger.kernel.org,
	maple-tree@lists.infradead.org,  kasan-dev@googlegroups.com
Subject: Re: [PATCH RFC v3 0/9] SLUB percpu array caches and maple tree nodes
Date: Thu, 14 Dec 2023 12:14:40 -0800 (PST)	[thread overview]
Message-ID: <146558f5-9f5c-e65f-0177-5f736fe663cd@linux.com> (raw)
In-Reply-To: <ZWerDCdvVkAfsStz@casper.infradead.org>

On Wed, 29 Nov 2023, Matthew Wilcox wrote:

>> In order to make the SLUB in page freelists work better you need to have
>> larger freelist and that comes with larger page sizes. I.e. boot with
>> slub_min_order=5 or so to increase performance.
>
> That comes with its own problems, of course.

Well I thought you were solving those with the folios?

>> Also this means increasing TLB pressure. The in page freelists of SLUB cause
>> objects from the same page be served. The SLAB queueing approach
>> results in objects being mixed from any address and thus neighboring objects
>> may require more TLB entries.
>
> Is that still a concern for modern CPUs?  We're using 1GB TLB entries
> these days, and there are usually thousands of TLB entries.  This feels
> like more of a concern for a 90s era CPU.

ARM kernel memory is mapped by 4K entries by default since rodata=full is 
the default. Security concerns screw it up.




  reply	other threads:[~2023-12-14 20:14 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-29  9:53 [PATCH RFC v3 0/9] SLUB percpu array caches and maple tree nodes Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 1/9] mm/slub: fix bulk alloc and free stats Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 2/9] mm/slub: introduce __kmem_cache_free_bulk() without free hooks Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 3/9] mm/slub: handle bulk and single object freeing separately Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 4/9] mm/slub: free KFENCE objects in slab_free_hook() Vlastimil Babka
2023-11-29 12:00   ` Marco Elver
2023-11-29  9:53 ` [PATCH RFC v3 5/9] mm/slub: add opt-in percpu array cache of objects Vlastimil Babka
2023-11-29 10:35   ` Marco Elver
2023-12-15 18:28   ` Suren Baghdasaryan
2023-12-15 21:17     ` Suren Baghdasaryan
2023-11-29  9:53 ` [PATCH RFC v3 6/9] tools: Add SLUB percpu array functions for testing Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 7/9] maple_tree: use slub percpu array Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 8/9] maple_tree: Remove MA_STATE_PREALLOC Vlastimil Babka
2023-11-29  9:53 ` [PATCH RFC v3 9/9] maple_tree: replace preallocation with slub percpu array prefill Vlastimil Babka
2023-11-29 20:16 ` [PATCH RFC v3 0/9] SLUB percpu array caches and maple tree nodes Christoph Lameter (Ampere)
2023-11-29 21:20   ` Matthew Wilcox
2023-12-14 20:14     ` Christoph Lameter (Ampere) [this message]
2023-11-30  9:14   ` Vlastimil Babka

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