<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>probe::ioblock.request</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"><link rel="home" href="index.html" title="SystemTap Tapset Reference Manual"><link rel="up" href="ch07.html" title="Chapter 7. IO Scheduler and block IO Tapset"><link rel="prev" href="re117.html" title="probe::ioscheduler_trace.unplug_timer"><link rel="next" href="re119.html" title="probe::ioblock.end"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>probe::ioblock.request</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re117.html">Prev</a> </td><th width="60%" align="center">Chapter 7. IO Scheduler and block IO Tapset</th><td width="20%" align="right"> <a accesskey="n" href="re119.html">Next</a></td></tr></table><hr></div><div class="refentry" title="probe::ioblock.request"><a name="API-ioblock-request"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>probe::ioblock.request — Fires whenever making a generic block I/O request. </p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="synopsis">ioblock.request </pre></div><div class="refsect1" title="Values"><a name="id3119242"></a><h2>Values</h2><p> None </p></div><div class="refsect1" title="Description"><a name="id3119252"></a><h2>Description</h2><p> </p><p> <em class="parameter"><code>devname</code></em> - block device name <em class="parameter"><code>ino</code></em> - i-node number of the mapped file <em class="parameter"><code>sector</code></em> - beginning sector for the entire bio <em class="parameter"><code>flags</code></em> - see below BIO_UPTODATE 0 ok after I/O completion BIO_RW_BLOCK 1 RW_AHEAD set, and read/write would block BIO_EOF 2 out-out-bounds error BIO_SEG_VALID 3 nr_hw_seg valid BIO_CLONED 4 doesn't own data BIO_BOUNCED 5 bio is a bounce bio BIO_USER_MAPPED 6 contains user pages BIO_EOPNOTSUPP 7 not supported </p><p> <em class="parameter"><code>rw</code></em> - binary trace for read/write request <em class="parameter"><code>vcnt</code></em> - bio vector count which represents number of array element (page, offset, length) which make up this I/O request <em class="parameter"><code>idx</code></em> - offset into the bio vector array <em class="parameter"><code>phys_segments</code></em> - number of segments in this bio after physical address coalescing is performed <em class="parameter"><code>hw_segments</code></em> - number of segments after physical and DMA remapping hardware coalescing is performed <em class="parameter"><code>size</code></em> - total size in bytes <em class="parameter"><code>bdev</code></em> - target block device <em class="parameter"><code>bdev_contains</code></em> - points to the device object which contains the partition (when bio structure represents a partition) <em class="parameter"><code>p_start_sect</code></em> - points to the start sector of the partition structure of the device </p></div><div class="refsect1" title="Context"><a name="id3119354"></a><h2>Context</h2><p> The process makes block I/O request </p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re117.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch07.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re119.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>probe::ioscheduler_trace.unplug_timer</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>probe::ioblock.end</span></td></tr></table></div></body></html>