From 21a67b797e40df930b83bd407ffc165b3f4b91b2 Mon Sep 17 00:00:00 2001 From: Filipe David Manana Date: Mon, 26 Apr 2010 13:04:40 +0200 Subject: 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. --- erts/emulator/drivers/common/ram_file_drv.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'erts/emulator/drivers/common/ram_file_drv.c') diff --git a/erts/emulator/drivers/common/ram_file_drv.c b/erts/emulator/drivers/common/ram_file_drv.c index d4e547ade6..abedcc933a 100644 --- a/erts/emulator/drivers/common/ram_file_drv.c +++ b/erts/emulator/drivers/common/ram_file_drv.c @@ -46,6 +46,8 @@ #define RAM_FILE_UUENCODE 35 /* uuencode file */ #define RAM_FILE_UUDECODE 36 /* uudecode file */ #define RAM_FILE_SIZE 37 /* get file size */ +#define RAM_FILE_ADVISE 38 /* predeclare the access + * pattern for file data */ /* possible new operations include: DES_ENCRYPT DES_DECRYPT @@ -693,6 +695,13 @@ static void rfile_command(ErlDrvData e, char* buf, int count) case RAM_FILE_UUDECODE: /* uudecode file */ ram_file_uudecode(f); break; + + case RAM_FILE_ADVISE: + if (f->flags == 0) + error_reply(f, EBADF); + else + reply(f, 1, 0); + break; } /* * Ignore anything else -- let the caller hang. -- cgit v1.2.3