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Message-ID: <53BBFE08.1080804@selasky.org>
Date: Tue, 08 Jul 2014 16:19:52 +0200
From: Hans Petter Selasky <hps@selasky.org>
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To: pyunyh@gmail.com
Subject: Re: [RFC] Allow m_dup() to use JUMBO clusters
References: <53BA5657.8010309@selasky.org>
 <20140708021439.GA3965@michelle.fasterthan.com>
 <53BB7433.2010306@selasky.org>
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>
> Hi,
>
> Would it be better if my patch used the PAGE_SIZE clusters instead of
> the 16K ones? Then it should not be affected by memory defragmentation.
> Thanks for shedding some light into this area?
>
> --HPS
>

Hi,

Updated patch attached.

--HPS

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=== sys/kern/uipc_mbuf.c
==================================================================
--- sys/kern/uipc_mbuf.c	(revision 268358)
+++ sys/kern/uipc_mbuf.c	(local)
@@ -917,7 +917,15 @@
 		struct mbuf *n;
 
 		/* Get the next new mbuf */
-		if (remain >= MINCLSIZE) {
+		if (remain >= MJUMPAGESIZE) {
+			/*
+			 * By allocating a bigger mbuf, we get fewer
+			 * scatter gather entries for the hardware to
+			 * process:
+			 */
+			n = m_getjcl(how, m->m_type, 0, MJUMPAGESIZE);
+			nsize = MJUMPAGESIZE;
+		} else if (remain >= MINCLSIZE) {
 			n = m_getcl(how, m->m_type, 0);
 			nsize = MCLBYTES;
 		} else {

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