page_cache_sync_readahead(9) [centos man page]

PAGE_CACHE_SYNC_READ(9) 				    Memory Management in Linux					   PAGE_CACHE_SYNC_READ(9)

NAME

       page_cache_sync_readahead - generic file readahead

SYNOPSIS

       void page_cache_sync_readahead(struct address_space * mapping, struct file_ra_state * ra, struct file * filp, pgoff_t offset,
				      unsigned long req_size);

ARGUMENTS

       mapping
	   address_space which holds the pagecache and I/O vectors

       ra
	   file_ra_state which holds the readahead state

       filp
	   passed on to ->readpage and ->readpages

       offset
	   start offset into mapping, in pagecache page-sized units

       req_size
	   hint: total size of the read which the caller is performing in pagecache pages

DESCRIPTION

       page_cache_sync_readahead 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.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   PAGE_CACHE_SYNC_READ(9)

VFS_READAHEAD(8)					    System Administration tools 					  VFS_READAHEAD(8)

NAME

       vfs_readahead - pre-load the kernel buffer cache

SYNOPSIS

       vfs objects = readahead

DESCRIPTION

       This VFS module is part of the samba(7) suite.

       This vfs_readahead VFS module detects read requests at multiples of a given offset (hex 0x80000 by default) and then tells the kernel via
       either the readahead system call (on Linux) or the posix_fadvise system call to pre-fetch this data into the buffer cache.

       This module is useful for Windows Vista clients reading data using the Windows Explorer program, which asynchronously does multiple file
       read requests at offset boundaries of 0x80000 bytes.

       The offset multiple used is given by the readahead:offset option, which defaults to 0x80000.

       The size of the disk read operations performed by vfs_readahead is determined by the readahead:length option. By default this is set to the
       same value as the readahead:offset option and if not set explicitly will use the current value of readahead:offset.

       This module is stackable.

OPTIONS

       readahead:offset = BYTES
	   The offset multiple that causes readahead to be requested of the kernel buffer cache.

       readahead:length = BYTES
	   The number of bytes requested to be read into the kernel buffer cache on each readahead call.

       The following suffixes may be applied to BYTES:

       o   K - BYTES is a number of kilobytes

       o   M - BYTES is a number of megabytes

       o   G - BYTES is a number of gigabytes

EXAMPLES

		[hypothetical]
		vfs objects = readahead

VERSION

       This man page is correct for version 3.0.25 of the Samba suite.

AUTHOR

       The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

Samba 4.0							    06/17/2014							  VFS_READAHEAD(8)