diff --git a/man2/readahead.2 b/man2/readahead.2 index 1b0376e1c..088dbf951 100644 --- a/man2/readahead.2 +++ b/man2/readahead.2 @@ -25,7 +25,7 @@ .\" 2004-05-40 Created by Michael Kerrisk .\" 2004-10-05 aeb, minor correction .\" -.TH READAHEAD 2 2013-04-01 "Linux" "Linux Programmer's Manual" +.TH READAHEAD 2 2014-03-15 "Linux" "Linux Programmer's Manual" .SH NAME readahead \- initiate file readahead into page cache .SH SYNOPSIS @@ -37,8 +37,11 @@ readahead \- initiate file readahead into page cache .fi .SH DESCRIPTION .BR readahead () -initates readahead on a file so that subsequent reads from that file will -hopefully be satisfied from the cache, and not block on disk I/O. +initiates readahead on a file so that subsequent reads from that file will, +be satisfied from the cache, and not block on disk I/O +(assuming the readahead was initiated early enough and that other activity +on the system did not in the meantime flush pages from the cache). + The .I fd argument is a file descriptor identifying the file which is @@ -93,10 +96,12 @@ the calling signature for this system call differs, for the reasons described in .BR syscall (2). -The call attempts to schedule the reads in the background and return -immediately, however it may block while reading filesystem metadata -in order to locate where the blocks requested are. This occurs frequently -with ext[234] on large files using indirect blocks instead of extents, +.BR readahead () +attempts to schedule the reads in the background and return immediately. +However, it may block while it reads the filesystem metadata needed +to locate the requested blocks. +This occurs frequently with ext[234] on large files +using indirect blocks instead of extents, giving the appearence that the call blocks until the requested data has been read. .SH SEE ALSO