<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>probe::ioblock_trace.request</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1"><link rel="home" href="index.html" title="SystemTap Tapset Reference Manual"><link rel="up" href="iosched.stp.html" title="Chapter 9. IO Scheduler and block IO Tapset"><link rel="prev" href="API-ioblock-trace-end.html" title="probe::ioblock_trace.end"><link rel="next" href="API-ioscheduler-elv-add-request.html" title="probe::ioscheduler.elv_add_request"></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_trace.request</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-ioblock-trace-end.html">Prev</a> </td><th width="60%" align="center">Chapter 9. IO Scheduler and block IO Tapset</th><td width="20%" align="right"> <a accesskey="n" href="API-ioscheduler-elv-add-request.html">Next</a></td></tr></table><hr></div><div class="refentry" title="probe::ioblock_trace.request"><a name="API-ioblock-trace-request"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>probe::ioblock_trace.request —
Fires just as a generic block I/O request is created for a bio.
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="synopsis">ioblock_trace.request </pre></div><div class="refsect1" title="Values"><a name="idp4020008"></a><h2>Values</h2><p>
None
</p></div><div class="refsect1" title="Description"><a name="idp4020616"></a><h2>Description</h2><p>
</p><p>
<em class="parameter"><code>name</code></em> - name of the probe point
<em class="parameter"><code>q</code></em> - request queue on which this bio was queued.
<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>bytes_done</code></em> - number of bytes transferred
<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>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="idp4027896"></a><h2>Context</h2><p>
The process makes block I/O request
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