kernel-ark/mm
Andrew Morton 60c371bc75 [PATCH] fadvise() make POSIX_FADV_NOREUSE a no-op
The POSIX_FADV_NOREUSE hint means "the application will use this range of the
file a single time".  It seems to be intended that the implementation will use
this hint to perform drop-behind of that part of the file when the application
gets around to reading or writing it.

However for reasons which aren't obvious (or sane?) I mapped
POSIX_FADV_NOREUSE onto POSIX_FADV_WILLNEED.  ie: it does readahead.

That's daft.  So for now, make POSIX_FADV_NOREUSE a no-op.

This is a non-back-compatible change.  If someone was using POSIX_FADV_NOREUSE
to perform readahead, they lose.  The likelihood is low.

If/when we later implement POSIX_FADV_NOREUSE things will get interesting - to
do it fully we'll need to maintain file offset/length ranges and peform all
sorts of complex tricks, and managing the lifetime of those ranges' data
structures will be interesting..

A sensible implementation would probably ignore the file range and would
simply mark the entire file as needing some form of drop-behind treatment.

Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-06 08:57:47 -07:00
..
bootmem.c
fadvise.c [PATCH] fadvise() make POSIX_FADV_NOREUSE a no-op 2006-08-06 08:57:47 -07:00
filemap_xip.c
filemap.c
filemap.h
fremap.c
highmem.c
hugetlb.c
internal.h
Kconfig
madvise.c
Makefile
memory_hotplug.c
memory.c
mempolicy.c
mempool.c
migrate.c
mincore.c
mlock.c
mmap.c
mmzone.c
mprotect.c
mremap.c
msync.c
nommu.c
oom_kill.c
page_alloc.c
page_io.c
page-writeback.c
pdflush.c
prio_tree.c
readahead.c
rmap.c
shmem.c
slab.c [PATCH] Fix kmem_cache_alloc() been documented twice 2006-07-31 13:28:43 -07:00
slob.c
sparse.c
swap_state.c
swap.c
swapfile.c
thrash.c
tiny-shmem.c
truncate.c
util.c
vmalloc.c
vmscan.c
vmstat.c