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
next 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).