From: Matthew Wilcox <willy@infradead.org>
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Suren Baghdasaryan <surenb@google.com>,
akpm@linux-foundation.org, lorenzo.stoakes@oracle.com,
mhocko@suse.com, hannes@cmpxchg.org, mjguzik@gmail.com,
oliver.sang@intel.com, mgorman@techsingularity.net,
david@redhat.com, peterx@redhat.com, oleg@redhat.com,
dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org,
dhowells@redhat.com, hdanton@sina.com, hughd@google.com,
minchan@google.com, jannh@google.com, shakeel.butt@linux.dev,
souravpanda@google.com, pasha.tatashin@soleen.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@android.com
Subject: Re: [PATCH v2 4/5] mm: make vma cache SLAB_TYPESAFE_BY_RCU
Date: Wed, 13 Nov 2024 13:57:07 +0000 [thread overview]
Message-ID: <ZzSwM5qwStadOZvv@casper.infradead.org> (raw)
In-Reply-To: <sdfh56itaffzhpk4rft2tsjm7r44auhjomfthzgxzrmj5632eq@noi2uhgp3a3h>
On Wed, Nov 13, 2024 at 07:38:02AM -0500, Liam R. Howlett wrote:
> > Hi, I was wondering if we actually need the detached flag. Couldn't
> > "detached" simply mean vma->vm_mm == NULL and we save 4 bytes? Do we ever
> > need a vma that's detached but still has a mm pointer? I'd hope the places
> > that set detached to false have the mm pointer around so it's not inconvenient.
>
> I think the gate vmas ruin this plan.
But the gate VMAs aren't to be found in the VMA tree. Used to be that
was because the VMA tree was the injective RB tree and so VMAs could
only be in one tree at a time. We could change that now!
Anyway, we could use (void *)1 instead of NULL to indicate a "detached"
VMA if we need to distinguish between a detached VMA and a gate VMA.
next prev parent reply other threads:[~2024-11-13 13:57 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-12 19:46 [PATCH v2 0/5] move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-12 19:46 ` [PATCH v2 1/5] mm: introduce vma_start_read_locked{_nested} helpers Suren Baghdasaryan
2024-11-13 14:10 ` Lorenzo Stoakes
2024-11-13 15:30 ` Suren Baghdasaryan
2024-11-12 19:46 ` [PATCH v2 2/5] mm: move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-13 14:28 ` Lorenzo Stoakes
2024-11-13 14:45 ` Vlastimil Babka
2024-11-13 14:58 ` Lorenzo Stoakes
2024-11-13 15:09 ` Vlastimil Babka
2024-11-13 14:53 ` Mateusz Guzik
2024-11-13 14:59 ` Lorenzo Stoakes
2024-11-13 15:01 ` Lorenzo Stoakes
2024-11-13 15:45 ` Suren Baghdasaryan
2024-11-13 15:42 ` Suren Baghdasaryan
2024-11-12 19:46 ` [PATCH v2 3/5] mm: mark vma as detached until it's added into vma tree Suren Baghdasaryan
2024-11-13 14:43 ` Lorenzo Stoakes
2024-11-13 15:37 ` Suren Baghdasaryan
2024-11-12 19:46 ` [PATCH v2 4/5] mm: make vma cache SLAB_TYPESAFE_BY_RCU Suren Baghdasaryan
2024-11-13 2:57 ` Suren Baghdasaryan
2024-11-13 5:08 ` Hugh Dickins
2024-11-13 6:03 ` Suren Baghdasaryan
2024-11-13 6:52 ` Hugh Dickins
2024-11-13 8:19 ` Suren Baghdasaryan
2024-11-13 8:58 ` Vlastimil Babka
2024-11-13 12:38 ` Liam R. Howlett
2024-11-13 13:57 ` Matthew Wilcox [this message]
2024-11-13 15:22 ` Liam R. Howlett
2024-11-13 15:25 ` Suren Baghdasaryan
2024-11-13 15:29 ` Liam R. Howlett
2024-11-13 15:47 ` Suren Baghdasaryan
2024-11-13 19:05 ` Suren Baghdasaryan
2024-11-14 16:18 ` Suren Baghdasaryan
2024-11-14 16:21 ` Vlastimil Babka
2024-11-13 16:44 ` Jann Horn
2024-11-13 20:59 ` Matthew Wilcox
2024-11-13 21:23 ` Jann Horn
2024-11-12 19:46 ` [PATCH v2 5/5] docs/mm: document latest changes to vm_lock Suren Baghdasaryan
2024-11-12 19:51 ` Suren Baghdasaryan
2024-11-13 14:46 ` Lorenzo Stoakes
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=ZzSwM5qwStadOZvv@casper.infradead.org \
--to=willy@infradead.org \
--cc=Liam.Howlett@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=brauner@kernel.org \
--cc=dave@stgolabs.net \
--cc=david@redhat.com \
--cc=dhowells@redhat.com \
--cc=hannes@cmpxchg.org \
--cc=hdanton@sina.com \
--cc=hughd@google.com \
--cc=jannh@google.com \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lorenzo.stoakes@oracle.com \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=minchan@google.com \
--cc=mjguzik@gmail.com \
--cc=oleg@redhat.com \
--cc=oliver.sang@intel.com \
--cc=pasha.tatashin@soleen.com \
--cc=paulmck@kernel.org \
--cc=peterx@redhat.com \
--cc=shakeel.butt@linux.dev \
--cc=souravpanda@google.com \
--cc=surenb@google.com \
--cc=vbabka@suse.cz \
/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