From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.com, vbabka@suse.cz, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: kmalloc_index: remove case when size is more than 32MB
Date: Sun, 9 May 2021 14:33:38 +0900 [thread overview]
Message-ID: <CAB=+i9QyxOu_1QDfX5QA=pOxxnRURPnwd2Y0EbhoO1u0e=irBA@mail.gmail.com> (raw)
In-Reply-To: <YJccjBMBiwLqFrB8@casper.infradead.org>
On Sun, May 09, 2021 at 12:19:40AM +0100, Matthew Wilcox wrote:
> On Sun, May 09, 2021 at 07:13:28AM +0900, Hyeonggon Yoo wrote:
> > the return value of kmalloc_index is used as index of kmalloc_caches,
>
> it doesn't matter. every few weeks somebody posts a patch to "optimise"
> kmalloc_index, failing to appreciate that it's only ever run at compile
> time because it's all under __builtin_constant_p().
Oh thanks, I didn't know about __builtin_constant_p.
But I was not optimizing kmalloc_index. isn't it confusing that
kmalloc_caches alllows maximum size of 32MB, and kmalloc_index allows
maximum size of 64MB?
and even if the code I removed is never reached because 64MB is always
bigger than KMALLOC_MAX_CACHE_SIZE, it will cause an error if reached.
next prev parent reply other threads:[~2021-05-09 5:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 22:13 [PATCH] mm: kmalloc_index: remove case when size is more than 32MB Hyeonggon Yoo
2021-05-08 23:19 ` Matthew Wilcox
2021-05-09 5:33 ` Hyeonggon Yoo [this message]
2021-05-10 10:09 ` Vlastimil Babka
2021-05-10 13:58 ` Hyeonggon Yoo
2021-05-10 14:04 ` Vlastimil Babka
2021-05-10 15:02 ` [PATCH v2] mm: kmalloc_index: make compiler break when size is not supported Hyeonggon Yoo
2021-05-10 15:15 ` Christoph Lameter
2021-05-10 15:21 ` Vlastimil Babka
2021-05-11 3:09 ` Hyeonggon Yoo
2021-05-10 15:19 ` Vlastimil Babka
2021-05-10 15:38 ` Hyeonggon Yoo
2021-05-11 8:36 ` Vlastimil Babka
2021-05-11 8:37 ` Vlastimil Babka
2021-05-11 9:14 ` Hyeonggon Yoo
2021-05-11 2:59 ` [PATCH v3] mm: change run-time assertion in kmalloc_index() to compile-time Hyeonggon Yoo
2021-05-10 15:44 ` [PATCH v2] mm: kmalloc_index: make compiler break when size is not supported Matthew Wilcox
2021-05-11 3:03 ` Hyeonggon Yoo
2021-05-11 8:33 ` Vlastimil Babka
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='CAB=+i9QyxOu_1QDfX5QA=pOxxnRURPnwd2Y0EbhoO1u0e=irBA@mail.gmail.com' \
--to=42.hyeyoo@gmail.com \
--cc=cl@linux.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=vbabka@suse.cz \
--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).