From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: akpm@osdl.org, linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] change pagevec counters back to unsigned long and cacheline align
Date: Mon, 18 Oct 2004 13:04:44 -0200 [thread overview]
Message-ID: <20041018150444.GD2403@logos.cnet> (raw)
Change pagevec "nr" and "cold" back to "unsigned long",
because 4 byte accesses can be slow on architectures < Pentium III
(additional "data16" operand on instruction).
This still honours the cacheline alignment, making the size
of "pagevec" structure a power of two (either 64 or 128 bytes).
Haven't been able to see any significant change on performance on my
limited testing.
--- rc4-mm1.orig/include/linux/pagevec.h 2004-10-15 01:02:39.209481760 -0300
+++ rc4-mm1/include/linux/pagevec.h 2004-10-15 01:17:58.853674592 -0300
@@ -5,14 +5,15 @@
* pages. A pagevec is a multipage container which is used for that.
*/
-#define PAGEVEC_SIZE 15
+/* 14 pointers + two long's align the pagevec structure to a power of two */
+#define PAGEVEC_SIZE 14
struct page;
struct address_space;
struct pagevec {
- unsigned short nr;
- unsigned short cold;
+ unsigned long nr;
+ unsigned long cold;
struct page *pages[PAGEVEC_SIZE];
};
----- End forwarded message -----
WARNING: multiple messages have this Message-ID (diff)
From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: akpm@osdl.org, linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] change pagevec counters back to unsigned long and cacheline align
Date: Mon, 18 Oct 2004 13:04:44 -0200 [thread overview]
Message-ID: <20041018150444.GD2403@logos.cnet> (raw)
Change pagevec "nr" and "cold" back to "unsigned long",
because 4 byte accesses can be slow on architectures < Pentium III
(additional "data16" operand on instruction).
This still honours the cacheline alignment, making the size
of "pagevec" structure a power of two (either 64 or 128 bytes).
Haven't been able to see any significant change on performance on my
limited testing.
--- rc4-mm1.orig/include/linux/pagevec.h 2004-10-15 01:02:39.209481760 -0300
+++ rc4-mm1/include/linux/pagevec.h 2004-10-15 01:17:58.853674592 -0300
@@ -5,14 +5,15 @@
* pages. A pagevec is a multipage container which is used for that.
*/
-#define PAGEVEC_SIZE 15
+/* 14 pointers + two long's align the pagevec structure to a power of two */
+#define PAGEVEC_SIZE 14
struct page;
struct address_space;
struct pagevec {
- unsigned short nr;
- unsigned short cold;
+ unsigned long nr;
+ unsigned long cold;
struct page *pages[PAGEVEC_SIZE];
};
----- End forwarded message -----
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
next reply other threads:[~2004-10-19 15:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-18 15:04 Marcelo Tosatti [this message]
2004-10-18 15:04 ` [PATCH] change pagevec counters back to unsigned long and cacheline align Marcelo Tosatti
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=20041018150444.GD2403@logos.cnet \
--to=marcelo.tosatti@cyclades.com \
--cc=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.