From: David Hildenbrand <david@redhat.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, Kent Overstreet <kent.overstreet@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [RFC] pgflags_t
Date: Wed, 6 Oct 2021 17:32:39 +0200 [thread overview]
Message-ID: <21ce511e-7cde-8bdb-b6c6-e1278681ebf6@redhat.com> (raw)
In-Reply-To: <YV3ArQxQ7CFzhBhR@zeniv-ca.linux.org.uk>
On 06.10.21 17:28, Al Viro wrote:
> On Wed, Oct 06, 2021 at 05:23:49PM +0200, David Hildenbrand wrote:
>> On 06.10.21 17:22, Al Viro wrote:
>>> On Wed, Oct 06, 2021 at 03:58:14PM +0100, Matthew Wilcox wrote:
>>>> David expressed some unease about the lack of typesafety in patches
>>>> 1 & 2 of the page->slab conversion [1], and I'll admit to not being
>>>> particularly a fan of passing around an unsigned long. That crystallised
>>>> in a discussion with Kent [2] about how to lock a page when you don't know
>>>> its type (solution: every memory descriptor type starts with a
>>>> pgflags_t)
>>>
>>> Why bother making it a struct? What's wrong with __bitwise and letting
>>> sparse catch conversions?
>>>
>>
>> As I raised in my reply, we store all kinds of different things in
>> page->flags ... not sure if that could be worked around somehow.
>
> What of that? Inline helpers with force-casts for accessing those and
> that's it...
It feels to me like using __bitwise for access checks and then still
modifying the __bitwise fields randomly via a backdoor. But sure, if it
works, I'll be happy if we can use that.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-10-06 15:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-06 14:58 [RFC] pgflags_t Matthew Wilcox
2021-10-06 15:16 ` David Hildenbrand
2021-10-06 15:29 ` Matthew Wilcox
2021-10-06 15:22 ` Al Viro
2021-10-06 15:23 ` David Hildenbrand
2021-10-06 15:28 ` Al Viro
2021-10-06 15:32 ` David Hildenbrand [this message]
2021-10-06 15:46 ` Al Viro
2021-10-06 15:47 ` David Hildenbrand
2021-10-06 15:38 ` Matthew Wilcox
2021-10-06 15:48 ` Al Viro
2021-10-07 14:37 ` Vlastimil Babka
2021-10-07 14:48 ` Matthew Wilcox
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=21ce511e-7cde-8bdb-b6c6-e1278681ebf6@redhat.com \
--to=david@redhat.com \
--cc=hannes@cmpxchg.org \
--cc=kent.overstreet@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/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;
as well as URLs for NNTP newsgroup(s).