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| author | Filipe David Manana <[email protected]> | 2010-04-26 13:04:40 +0200 |
|---|---|---|
| committer | Raimo Niskanen <[email protected]> | 2010-05-20 15:48:17 +0200 |
| commit | 21a67b797e40df930b83bd407ffc165b3f4b91b2 (patch) | |
| tree | 268a10e8d1d4cd00c30d3f5ded8f103d9699167a /lib/kernel/src/file.erl | |
| parent | 3f53a96a8bd0cd4a18f819b6857e6a764706ede5 (diff) | |
| download | otp-21a67b797e40df930b83bd407ffc165b3f4b91b2.tar.gz otp-21a67b797e40df930b83bd407ffc165b3f4b91b2.tar.bz2 otp-21a67b797e40df930b83bd407ffc165b3f4b91b2.zip | |
Add file:advise/4 - a wrapper to the POSIX syscall posix_fadvise
Useful for informing the Operating System about the access pattern
for a file's data, so that it can adapt the caching strategy to
maximize disk IO performance.
Diffstat (limited to 'lib/kernel/src/file.erl')
| -rw-r--r-- | lib/kernel/src/file.erl | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl index 5da359fdf1..a694ed0708 100644 --- a/lib/kernel/src/file.erl +++ b/lib/kernel/src/file.erl @@ -36,7 +36,7 @@ %% Specialized -export([ipread_s32bu_p32bu/3]). %% Generic file contents. --export([open/2, close/1, +-export([open/2, close/1, advise/4, read/2, write/2, pread/2, pread/3, pwrite/2, pwrite/3, read_line/1, @@ -89,6 +89,8 @@ -type date() :: {pos_integer(), pos_integer(), pos_integer()}. -type time() :: {non_neg_integer(), non_neg_integer(), non_neg_integer()}. -type date_time() :: {date(), time()}. +-type posix_file_advise() :: 'normal' | 'sequential' | 'random' | 'no_reuse' | + 'will_need' | 'dont_need'. %%%----------------------------------------------------------------- %%% General functions @@ -352,6 +354,18 @@ close(#file_descriptor{module = Module} = Handle) -> close(_) -> {error, badarg}. +-spec advise(File :: io_device(), Offset :: integer(), + Length :: integer(), Advise :: posix_file_advise()) -> + 'ok' | {'error', posix()}. + +advise(File, Offset, Length, Advise) when is_pid(File) -> + R = file_request(File, {advise, Offset, Length, Advise}), + wait_file_reply(File, R); +advise(#file_descriptor{module = Module} = Handle, Offset, Length, Advise) -> + Module:advise(Handle, Offset, Length, Advise); +advise(_, _, _, _) -> + {error, badarg}. + -spec read(File :: io_device(), Size :: non_neg_integer()) -> 'eof' | {'ok', [char()] | binary()} | {'error', posix()}. |