LKML: Jesper Juhl: [PATCH] Reduce nr of ptr derefs in fs/jffs2/summary.c

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>LKML: Jesper Juhl: [PATCH] Reduce nr of ptr derefs in fs/jffs2/summary.c</title><link href="/css/message.css" rel="stylesheet" type="text/css" /><link href="/css/wrap.css" rel="alternate stylesheet" type="text/css" title="wrap" /><link href="/css/nowrap.css" rel="stylesheet" type="text/css" title="nowrap" /><link href="/favicon.ico" rel="shortcut icon" /><script src="/js/simple-calendar.js" type="text/javascript"></script><script src="/js/styleswitcher.js" type="text/javascript"></script><link rel="alternate" type="application/rss+xml" title="lkml.org : last 100 messages" href="/rss.php" /><link rel="alternate" type="application/rss+xml" title="lkml.org : last messages by Jesper Juhl" href="/groupie.php?aid=841" /><script> var _paq = window._paq = window._paq || []; /* tracker methods like "setCustomDimension" should be called before "trackPageView" */ _paq.push(["setDoNotTrack", true]); _paq.push(["disableCookies"]); _paq.push(['trackPageView']); _paq.push(['enableLinkTracking']); (function() { var u="//m.lkml.org/"; _paq.push(['setTrackerUrl', u+'matomo.php']); _paq.push(['setSiteId', '1']); var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); })(); </script></head><body onload="es.jasper.simpleCalendar.init();" itemscope="itemscope" itemtype="http://schema.org/BlogPosting"><table border="0" cellpadding="0" cellspacing="0"><tr><td width="180" align="center"><a href="/"><img style="border:0;width:135px;height:32px" src="/images/toprowlk.gif" alt="lkml.org" /></a></td><td width="32">聽</td><td class="nb"><div><a class="nb" href="/lkml"> [lkml]</a> 聽 <a class="nb" href="/lkml/2005"> [2005]</a> 聽 <a class="nb" href="/lkml/2005/12"> [Dec]</a> 聽 <a class="nb" href="/lkml/2005/12/11"> [11]</a> 聽 <a class="nb" href="/lkml/last100"> [last100]</a> 聽 <a href="/rss.php"><img src="/images/rss-or.gif" border="0" alt="RSS Feed" /></a></div><div>Views: <a href="#" class="nowrap" onclick="setActiveStyleSheet('wrap');return false;">[wrap]</a><a href="#" class="wrap" onclick="setActiveStyleSheet('nowrap');return false;">[no wrap]</a> 聽 <a class="nb" href="/lkml/mheaders/2005/12/11/6" onclick="this.href='/lkml/headers'+'/2005/12/11/6';">[headers]</a>聽 <a href="/lkml/bounce/2005/12/11/6">[forward]</a>聽 </div></td><td width="32">聽</td></tr><tr><td valign="top"><div class="es-jasper-simpleCalendar" baseurl="/lkml/"></div><div class="threadlist">Messages in this thread</div><ul class="threadlist"><li class="root"><a href="/lkml/2005/12/11/6">First message in thread</a></li><li class="origin"><a href="/lkml/2005/12/15/363">Jesper Juhl</a><ul><li><a href="/lkml/2005/12/15/363">Jan Engelhardt</a><ul><li><a href="/lkml/2005/12/15/451">Andy Isaacson</a><ul><li><a href="/lkml/2005/12/16/249">Jan Engelhardt</a></li></ul></li></ul></li></ul></li></ul><div class="threadlist">Patch in this message</div><ul class="threadlist"><li><a href="/lkml/diff/2005/12/11/6/1">Get diff 1</a></li></ul></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerl.gif" width="32" height="32" alt="/" /></td><td class="c" rowspan="2" valign="top" style="padding-top: 1em"><table><tr><td><table><tr><td class="lp">From</td><td class="rp" itemprop="author">Jesper Juhl <></td></tr><tr><td class="lp">Subject</td><td class="rp" itemprop="name">[PATCH] Reduce nr of ptr derefs in fs/jffs2/summary.c</td></tr><tr><td class="lp">Date</td><td class="rp" itemprop="datePublished">Sun, 11 Dec 2005 06:40:48 +0100</td></tr></table></td><td></td></tr></table><pre itemprop="articleBody">Here's a small patch to reduce the nr. of pointer dereferences in<br />fs/jffs2/summary.c<br /><br />Benefits:<br /> - micro speed optimization due to fewer pointer derefs<br /> - generated code is slightly smaller<br /> - better readability<br /><br />Please consider applying...<br /><br /><br />Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com><br />---<br /><br /> fs/jffs2/summary.c | 38 +++++++++++++++++++-------------------<br /> 1 files changed, 19 insertions(+), 19 deletions(-)<br /><br />orig:<br /> text data bss dec hex filename<br /> 5033 0 0 5033 13a9 fs/jffs2/summary.o<br />patched:<br /> text data bss dec hex filename<br /> 4935 0 0 4935 1347 fs/jffs2/summary.o<br /><br />--- linux-2.6.15-rc5-git1-orig/fs/jffs2/summary.c 2005-12-04 18:48:38.000000000 +0100<br />+++ linux-2.6.15-rc5-git1/fs/jffs2/summary.c 2005-12-11 06:01:51.000000000 +0100<br />@@ -581,16 +581,17 @@ static int jffs2_sum_write_data(struct j<br /> wpage = c->summary->sum_buf;<br /> <br /> while (c->summary->sum_num) {<br />+ temp = c->summary->sum_list_head;<br /> <br />- switch (je16_to_cpu(c->summary->sum_list_head->u.nodetype)) {<br />+ switch (je16_to_cpu(temp->u.nodetype)) {<br /> case JFFS2_NODETYPE_INODE: {<br /> struct jffs2_sum_inode_flash *sino_ptr = wpage;<br /> <br />- sino_ptr->nodetype = c->summary->sum_list_head->i.nodetype;<br />- sino_ptr->inode = c->summary->sum_list_head->i.inode;<br />- sino_ptr->version = c->summary->sum_list_head->i.version;<br />- sino_ptr->offset = c->summary->sum_list_head->i.offset;<br />- sino_ptr->totlen = c->summary->sum_list_head->i.totlen;<br />+ sino_ptr->nodetype = temp->i.nodetype;<br />+ sino_ptr->inode = temp->i.inode;<br />+ sino_ptr->version = temp->i.version;<br />+ sino_ptr->offset = temp->i.offset;<br />+ sino_ptr->totlen = temp->i.totlen;<br /> <br /> wpage += JFFS2_SUMMARY_INODE_SIZE;<br /> <br />@@ -600,19 +601,19 @@ static int jffs2_sum_write_data(struct j<br /> case JFFS2_NODETYPE_DIRENT: {<br /> struct jffs2_sum_dirent_flash *sdrnt_ptr = wpage;<br /> <br />- sdrnt_ptr->nodetype = c->summary->sum_list_head->d.nodetype;<br />- sdrnt_ptr->totlen = c->summary->sum_list_head->d.totlen;<br />- sdrnt_ptr->offset = c->summary->sum_list_head->d.offset;<br />- sdrnt_ptr->pino = c->summary->sum_list_head->d.pino;<br />- sdrnt_ptr->version = c->summary->sum_list_head->d.version;<br />- sdrnt_ptr->ino = c->summary->sum_list_head->d.ino;<br />- sdrnt_ptr->nsize = c->summary->sum_list_head->d.nsize;<br />- sdrnt_ptr->type = c->summary->sum_list_head->d.type;<br />+ sdrnt_ptr->nodetype = temp->d.nodetype;<br />+ sdrnt_ptr->totlen = temp->d.totlen;<br />+ sdrnt_ptr->offset = temp->d.offset;<br />+ sdrnt_ptr->pino = temp->d.pino;<br />+ sdrnt_ptr->version = temp->d.version;<br />+ sdrnt_ptr->ino = temp->d.ino;<br />+ sdrnt_ptr->nsize = temp->d.nsize;<br />+ sdrnt_ptr->type = temp->d.type;<br /> <br />- memcpy(sdrnt_ptr->name, c->summary->sum_list_head->d.name,<br />- c->summary->sum_list_head->d.nsize);<br />+ memcpy(sdrnt_ptr->name, temp->d.name,<br />+ temp->d.nsize);<br /> <br />- wpage += JFFS2_SUMMARY_DIRENT_SIZE(c->summary->sum_list_head->d.nsize);<br />+ wpage += JFFS2_SUMMARY_DIRENT_SIZE(temp->d.nsize);<br /> <br /> break;<br /> }<br />@@ -622,8 +623,7 @@ static int jffs2_sum_write_data(struct j<br /> }<br /> }<br /> <br />- temp = c->summary->sum_list_head;<br />- c->summary->sum_list_head = c->summary->sum_list_head->u.next;<br />+ c->summary->sum_list_head = temp->u.next;<br /> kfree(temp);<br /> <br /> c->summary->sum_num--;<br /><br /><br />-<br />To unsubscribe from this list: send the line "unsubscribe linux-kernel" in<br />the body of a message to majordomo@vger.kernel.org<br />More majordomo info at <a href="http://vger.kernel.org/majordomo-info.html">http://vger.kernel.org/majordomo-info.html</a><br />Please read the FAQ at <a href="http://www.tux.org/lkml/">http://www.tux.org/lkml/</a><br /><br /></pre></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerr.gif" width="32" height="32" alt="\" /></td></tr><tr><td align="right" valign="bottom"> 聽 </td></tr><tr><td align="right" valign="bottom">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerl.gif" width="32" height="32" alt="\" /></td><td class="c">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerr.gif" width="32" height="32" alt="/" /></td></tr><tr><td align="right" valign="top" colspan="2"> 聽 </td><td class="lm">Last update: 2005-12-11 06:42 聽聽 [from the cache]<br />漏2003-2020 <a href="http://blog.jasper.es/"><span itemprop="editor">Jasper Spaans</span></a>|hosted at <a href="https://www.digitalocean.com/?refcode=9a8e99d24cf9">Digital Ocean</a> and my Meterkast|<a href="http://blog.jasper.es/categories.html#lkml-ref">Read the blog</a></td><td>聽</td></tr></table><script language="javascript" src="/js/styleswitcher.js" type="text/javascript"></script></body></html>

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LKML: Jesper Juhl: [PATCH] Reduce nr of ptr derefs in fs/jffs2/summary.c