linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org, patches@lists.linux.dev,
	linux-kernel@vger.kernel.org, andrea.righi@canonical.com,
	keescook@chromium.org, zhumao001@208suo.com,
	yangtiezhu@loongson.cn, ojeda@kernel.org
Subject: Re: [GIT PULL] Modules changes for v6.7-rc1
Date: Wed, 1 Nov 2023 21:02:51 -1000	[thread overview]
Message-ID: <CAHk-=whFXNYXG2ES8HdoaMC=O4bakMXGZezmoqA3SXwn4xJUPQ@mail.gmail.com> (raw)
In-Reply-To: <ZUKxT1CL9/0Dn6NE@bombadil.infradead.org>

On Wed, 1 Nov 2023 at 10:13, Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> The only thing worth highligthing is that gzip moves to use vmalloc() instead of
> kmalloc just as we had a fix for this for zstd on v6.6-rc1.

Actually, that's almost certainly entirely the wrong thing to do.

Unless you *know* that the allocation is large, you shouldn't use
vmalloc(). And since kmalloc() has worked fine, you most definitely
don't know that.

So we have 'kvmalloc()' *exactly* for this reason, which is a "use
kmalloc, unless that is too small, then use vmalloc".

kmalloc() isn't just about "use physically contiguous allocations".
It's also more memory-efficient, and a *lot* faster than vmalloc(),
which has to play VM tricks.

So this "just switch to vmalloc()" is entirely wrong.

              Linus

  reply	other threads:[~2023-11-02  7:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-01 20:13 [GIT PULL] Modules changes for v6.7-rc1 Luis Chamberlain
2023-11-02  7:02 ` Linus Torvalds [this message]
2023-11-02  7:21   ` Linus Torvalds
2023-11-02  7:29     ` Andrea Righi
2023-11-02  8:19       ` Andrea Righi
2023-11-02  7:22   ` Andrea Righi
2023-11-02  7:23 ` pr-tracker-bot

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='CAHk-=whFXNYXG2ES8HdoaMC=O4bakMXGZezmoqA3SXwn4xJUPQ@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=andrea.righi@canonical.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-modules@vger.kernel.org \
    --cc=mcgrof@kernel.org \
    --cc=ojeda@kernel.org \
    --cc=patches@lists.linux.dev \
    --cc=yangtiezhu@loongson.cn \
    --cc=zhumao001@208suo.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;
as well as URLs for NNTP newsgroup(s).