From: Linus Torvalds <torvalds@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH 5/6] eventfs: get rid of dentry pointers without refcounts
Date: Tue, 30 Jan 2024 15:06:13 -0800 [thread overview]
Message-ID: <CAHk-=wiPWaiD5fwyXXHX-qgk6t2+0NM_KHzwiecvCBiNWZacHA@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wg=tFFTep3dDTVHKYZBdNj0+PV4a0-UR1sVR3K7RHPGFg@mail.gmail.com>
On Tue, 30 Jan 2024 at 14:56, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> With that, the base size of 'struct eventfs_inode' actually becomes 96
> bytes for me.
It can be shrunk some more.
The field ordering is suboptimal. Pointers are 8 bytes and 8-byte
aligned, but 'struct kref' is just 4 bytes, and 'struct eventfs_attr'
is 12 bytes and 4-byte aligned.
So if you pack all the 8-byte-aligned fields at the beginning, and the
4-byte-aligned ones at the end, you get 88 bytes.
At which point a name pointer would *just* fit in 96 bytes.
... and then some debug option is enabled, and it all goes to hell again.
Linus
next prev parent reply other threads:[~2024-01-30 23:06 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 19:03 [PATCH 1/6] tracefs: avoid using the ei->dentry pointer unnecessarily Linus Torvalds
2024-01-30 19:03 ` [PATCH 2/6] eventfsfs: initialize the tracefs inode properly Linus Torvalds
2024-01-30 19:48 ` Steven Rostedt
2024-01-30 19:56 ` Steven Rostedt
2024-01-30 19:49 ` Steven Rostedt
2024-01-30 19:03 ` [PATCH 3/6] tracefs: dentry lookup crapectomy Linus Torvalds
2024-01-30 23:26 ` Al Viro
2024-01-30 23:55 ` Steven Rostedt
2024-01-31 0:07 ` Al Viro
2024-01-31 0:23 ` Al Viro
2024-01-31 0:39 ` Linus Torvalds
2024-01-30 19:03 ` [PATCH 4/6] eventfs: remove unused 'd_parent' pointer field Linus Torvalds
2024-01-30 19:03 ` [PATCH 5/6] eventfs: get rid of dentry pointers without refcounts Linus Torvalds
2024-01-30 20:55 ` Steven Rostedt
2024-01-30 21:52 ` Linus Torvalds
2024-01-30 22:56 ` Steven Rostedt
2024-01-30 22:58 ` Linus Torvalds
2024-01-30 23:04 ` Steven Rostedt
2024-01-30 22:56 ` Linus Torvalds
2024-01-30 23:06 ` Linus Torvalds [this message]
2024-01-30 23:10 ` Steven Rostedt
2024-01-30 23:25 ` Linus Torvalds
2024-01-31 0:48 ` Al Viro
2024-01-31 5:09 ` Steven Rostedt
2024-01-31 5:25 ` Linus Torvalds
2024-01-31 5:33 ` Steven Rostedt
2024-01-31 5:57 ` Linus Torvalds
2024-01-31 6:20 ` Linus Torvalds
2024-01-31 12:57 ` Steven Rostedt
2024-01-31 13:14 ` Steven Rostedt
2024-01-31 18:08 ` Linus Torvalds
2024-01-31 18:39 ` Steven Rostedt
2024-01-30 19:03 ` [PATCH 6/6] eventfs: clean up dentry ops and add revalidate function Linus Torvalds
2024-01-30 21:25 ` Steven Rostedt
2024-01-30 21:36 ` Linus Torvalds
2024-01-31 1:12 ` Al Viro
2024-01-31 2:37 ` Linus Torvalds
2024-01-31 2:46 ` Al Viro
2024-01-31 3:39 ` Linus Torvalds
2024-01-31 4:28 ` Al Viro
2024-01-31 18:00 ` Steven Rostedt
2024-01-31 23:07 ` Masami Hiramatsu
2024-01-31 23:23 ` Steven Rostedt
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