From: Uladzislau Rezki <urezki@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Pranjal Arya <pranjal.arya@oss.qualcomm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Uladzislau Rezki <urezki@gmail.com>,
"Liam R. Howlett" <liam@infradead.org>,
Alice Ryhl <aliceryhl@google.com>,
Andrew Ballance <andrewjballance@gmail.com>,
linux-arm-msm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org,
Lorenzo Stoakes <ljs@kernel.org>,
Pranjal Shrivastava <praan@google.com>,
Will Deacon <will@kernel.org>,
Suzuki K Poulose <Suzuki.Poulose@arm.com>,
Neil Armstrong <neil.armstrong@linaro.org>,
Mostafa Saleh <smostafa@google.com>,
Balbir Singh <balbirs@nvidia.com>,
Suren Baghdasaryan <surenb@google.com>,
Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Shuah Khan <shuah@kernel.org>, Dev Jain <dev.jain@arm.com>,
Brendan Jackman <jackmanb@google.com>,
Puranjay Mohan <puranjay@kernel.org>,
Santosh Shukla <santosh.shukla@amd.com>,
Wyes Karny <wkarny@gmail.com>,
Sudeep Holla <sudeep.holla@kernel.org>
Subject: Re: [PATCH RFC 00/12] mm/vmalloc: migrate vmap_area indexing from rb-tree to maple-tree
Date: Mon, 15 Jun 2026 11:52:22 +0200 [thread overview]
Message-ID: <ai_LVreyRWx-RDEd@pc636> (raw)
In-Reply-To: <ai3kkIpaR0aT_6q5@casper.infradead.org>
On Sun, Jun 14, 2026 at 12:15:28AM +0100, Matthew Wilcox wrote:
> On Sat, Jun 13, 2026 at 10:49:42PM +0530, Pranjal Arya wrote:
> > vmalloc's free/busy/lazy area tracking is one of the last remaining
> > augmented-rb_tree consumers in the core mm allocators. The rest of
> > mm/ has been gradually consolidating range-keyed indexing around
> > maple_tree (notably the per-process VMA tree in mm/mmap.c), and
> > the underlying reason is a structural mismatch between rb_tree and
> > range tracking:
>
> First, and most importantly, I love this. The maple tree is undoubtedly
> the right data structure to use for this purpose.
>
> What I don't understand is why you maintain a separate "free" tree.
> It should not be necessary any more, but maybe you tried removing it
> already and found a performance problem?
>
We maintain it in order to split several entities. That prevents
interfering between allocated data and vmap-free-space manager.
So in that case one context can easily access allocated data, for
example vread iterator, etc., whereas another can do an allocation.
So by splitting parts i minimize lock-contention.
--
Uladzislau Rezki
next prev parent reply other threads:[~2026-06-15 9:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-13 17:19 [PATCH RFC 00/12] mm/vmalloc: migrate vmap_area indexing from rb-tree to maple-tree Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 01/12] mm/vmalloc: introduce maple_tree-based indexing for vmap_area Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 02/12] mm/vmalloc: convert allocation-side gap finding and insertion to maple_tree Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 03/12] mm/vmalloc: convert free, purge, and pcpu paths " Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 04/12] mm/vmalloc: finalize maple-only indexing and shrink struct vmap_area Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 05/12] mm/vmalloc: tighten failure handling under memory pressure Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 06/12] mm/vmalloc: tighten alloc/free hot paths Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 07/12] mm/vmalloc: consolidate occupied tree as authoritative index on hot path Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 08/12] mm/vmalloc: track lazy-purge queue as a list_head Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 09/12] mm/vmalloc: collapse busy-tree find-then-unlink into a single mas_erase Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 10/12] mm/vmalloc: per-CPU caching of free ranges from the maple_tree allocator Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 11/12] mm/vmalloc: O(1) lookup of cached vmap_areas with bounded fast-reject Pranjal Arya
2026-06-13 17:19 ` [PATCH RFC 12/12] mm/vmalloc: harden bump-allocator alloc/free against UBSAN array bounds Pranjal Arya
2026-06-13 23:15 ` [PATCH RFC 00/12] mm/vmalloc: migrate vmap_area indexing from rb-tree to maple-tree Matthew Wilcox
2026-06-15 9:52 ` Uladzislau Rezki [this message]
2026-06-14 6:35 ` [syzbot ci] " syzbot ci
2026-06-14 6:58 ` [PATCH RFC 00/12] " Uladzislau Rezki
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=ai_LVreyRWx-RDEd@pc636 \
--to=urezki@gmail.com \
--cc=Suzuki.Poulose@arm.com \
--cc=akpm@linux-foundation.org \
--cc=aliceryhl@google.com \
--cc=andrewjballance@gmail.com \
--cc=balbirs@nvidia.com \
--cc=dev.jain@arm.com \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=jackmanb@google.com \
--cc=liam@infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=maple-tree@lists.infradead.org \
--cc=neil.armstrong@linaro.org \
--cc=praan@google.com \
--cc=pranjal.arya@oss.qualcomm.com \
--cc=puranjay@kernel.org \
--cc=santosh.shukla@amd.com \
--cc=shuah@kernel.org \
--cc=smostafa@google.com \
--cc=sudeep.holla@kernel.org \
--cc=surenb@google.com \
--cc=will@kernel.org \
--cc=willy@infradead.org \
--cc=wkarny@gmail.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.