linux-usb.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-usb@vger.kernel.org
Subject: USB: usb.h: tweak struct urb to remove wasted space
Date: Fri, 1 Mar 2019 18:22:38 +0100	[thread overview]
Message-ID: <20190301172238.GA23800@kroah.com> (raw)

By moving one field around in 'struct urb' we reduce the size of the
structure by 8 bytes.

Before the patch on x86_64 the overall size of the structure as reported
by pahole was:
	/* size: 192, cachelines: 3, members: 30 */
	/* sum members: 184, holes: 2, sum holes: 8 */
After the patch we now have:
	/* size: 184, cachelines: 3, members: 30 */
	/* last cacheline: 56 bytes */

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/usb.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 5e49e82c4368..4229eb74bd2c 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1545,10 +1545,10 @@ typedef void (*usb_complete_t)(struct urb *);
 struct urb {
 	/* private: usb core and host controller only fields in the urb */
 	struct kref kref;		/* reference count of the URB */
+	int unlinked;			/* unlink error code */
 	void *hcpriv;			/* private data for host controller */
 	atomic_t use_count;		/* concurrent submissions counter */
 	atomic_t reject;		/* submissions will fail */
-	int unlinked;			/* unlink error code */
 
 	/* public: documented fields in the urb that can be used by drivers */
 	struct list_head urb_list;	/* list head for use by the urb's

             reply	other threads:[~2019-03-01 17:22 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-01 17:22 Greg Kroah-Hartman [this message]
  -- strict thread matches above, loose matches on Subject: below --
2019-03-01 19:44 USB: usb.h: tweak struct urb to remove wasted space Oliver Neukum
2019-03-02  8:00 Greg Kroah-Hartman
2019-03-02 13:51 Oliver Neukum
2019-03-02 14:36 Greg Kroah-Hartman
2019-03-04 18:31 Oliver Neukum

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=20190301172238.GA23800@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=linux-usb@vger.kernel.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).