'\" t
.\"     Title: page_cache_sync_readahead
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: Memory Management in Linux
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "PAGE_CACHE_SYNC_READ" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "Memory Management in Linux"
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.SH "NAME"
page_cache_sync_readahead \- generic file readahead
.SH "SYNOPSIS"
.HP \w'void\ page_cache_sync_readahead('u
.BI "void page_cache_sync_readahead(struct\ address_space\ *\ " "mapping" ", struct\ file_ra_state\ *\ " "ra" ", struct\ file\ *\ " "filp" ", pgoff_t\ " "offset" ", unsigned\ long\ " "req_size" ");"
.SH "ARGUMENTS"
.PP
\fImapping\fR
.RS 4
address_space which holds the pagecache and I/O vectors
.RE
.PP
\fIra\fR
.RS 4
file_ra_state which holds the readahead state
.RE
.PP
\fIfilp\fR
.RS 4
passed on to \->\fBreadpage\fR
and \->\fBreadpages\fR
.RE
.PP
\fIoffset\fR
.RS 4
start offset into
\fImapping\fR, in pagecache page\-sized units
.RE
.PP
\fIreq_size\fR
.RS 4
hint: total size of the read which the caller is performing in pagecache pages
.RE
.SH "DESCRIPTION"
.PP
\fBpage_cache_sync_readahead\fR
should be called when a cache miss happened: it will submit the read\&. The readahead logic may decide to piggyback more pages onto the read request if access patterns suggest it will improve performance\&.
.SH "COPYRIGHT"
.br