From: Jiri Slaby <jirislaby@kernel.org>
To: David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Brendan Jackman <jackmanb@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Julia Lawall <Julia.Lawall@inria.fr>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Michal Hocko <mhocko@suse.com>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>, Zi Yan <ziy@nvidia.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/3] mm: treewide: make get_free_pages() and return void *
Date: Mon, 20 Oct 2025 11:08:27 +0200 [thread overview]
Message-ID: <3b97b754-890a-46c6-b892-a0324d529a3d@kernel.org> (raw)
In-Reply-To: <635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com>
On 20. 10. 25, 11:02, David Hildenbrand wrote:
> Regarding the metadata overhead, in 2015 Linus wrote in that thread:
>
> "Long ago, allocating a page using kmalloc() was a bad idea, because
> there was overhead for it in the allocation and the code.
>
> These days, kmalloc() not only doesn't have the allocation overhead,
> but may actually scale better too, thanks to percpu caches etc."
>
> What's that status of that 10 years later?
AFAI skimmed through the code, for allocations > 2 pages
(KMALLOC_MAX_CACHE_SIZE) -- if size is a constant -- slub resorts to
alloc_pages().
For smaller ones (1 and 2 pages), there is a very little overhead in
struct slab -- mm people, please correct me if I am wrong.
thanks,
--
js
suse labs
next prev parent reply other threads:[~2025-10-20 9:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-18 9:29 Mike Rapoport
2025-10-18 9:30 ` [PATCH 1/3] mm, vc_screen: move __free() handler that frees a page to a common header Mike Rapoport
2025-10-18 17:59 ` Jiri Slaby
2025-10-18 9:30 ` [PATCH 2/3] mm, treewide: make get_free_pages() and friends return void * Mike Rapoport
2025-10-18 9:30 ` [PATCH 3/3] mm, treewide: make addr parameter of free_pages() " Mike Rapoport
2025-10-19 0:30 ` [PATCH 0/3] mm: treewide: make get_free_pages() and return " Matthew Wilcox
2025-10-19 14:25 ` Mike Rapoport
2025-10-20 8:54 ` Vlastimil Babka
2025-10-20 9:04 ` Jiri Slaby
2025-10-20 14:22 ` Mike Rapoport
2025-10-20 9:06 ` David Hildenbrand
2025-10-20 14:20 ` Mike Rapoport
2025-10-20 6:58 ` Jiri Slaby
2025-10-20 7:06 ` Jiri Slaby
2025-10-20 9:02 ` David Hildenbrand
2025-10-20 9:08 ` Jiri Slaby [this message]
2025-10-20 9:13 ` David Hildenbrand
2025-10-20 10:31 ` Vlastimil Babka
2025-10-20 11:21 ` David Hildenbrand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3b97b754-890a-46c6-b892-a0324d529a3d@kernel.org \
--to=jirislaby@kernel.org \
--cc=Julia.Lawall@inria.fr \
--cc=Liam.Howlett@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=hannes@cmpxchg.org \
--cc=jackmanb@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lorenzo.stoakes@oracle.com \
--cc=mhocko@suse.com \
--cc=rppt@kernel.org \
--cc=surenb@google.com \
--cc=vbabka@suse.cz \
--cc=willy@infradead.org \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox