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/configure.in | 1 + erts/emulator/drivers/common/efile_drv.c | 34 ++++++++++++++++++++++++++ erts/emulator/drivers/common/erl_efile.h | 2 ++ erts/emulator/drivers/common/ram_file_drv.c | 9 +++++++ erts/emulator/drivers/unix/unix_efile.c | 11 +++++++++ erts/emulator/drivers/win32/win_efile.c | 9 +++++++ erts/preloaded/src/prim_file.erl | 38 ++++++++++++++++++++++++++++- 7 files changed, 103 insertions(+), 1 deletion(-) (limited to 'erts') diff --git a/erts/configure.in b/erts/configure.in index f11aba1b15..63bf548c89 100644 --- a/erts/configure.in +++ b/erts/configure.in @@ -1054,6 +1054,7 @@ fi AC_SUBST(ERTS_BUILD_SMP_EMU) +AC_CHECK_FUNCS([posix_fadvise]) # diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c index b64d27de68..60ae4cb108 100644 --- a/erts/emulator/drivers/common/efile_drv.c +++ b/erts/emulator/drivers/common/efile_drv.c @@ -54,6 +54,7 @@ #define FILE_ALTNAME 28 #define FILE_READ_LINE 29 #define FILE_FDATASYNC 30 +#define FILE_FADVISE 31 /* Return codes */ @@ -358,6 +359,11 @@ struct t_data struct t_readdir_buf *first_buf; struct t_readdir_buf *last_buf; } read_dir; + struct { + Sint64 offset; + Sint64 length; + int advise; + } fadvise; } c; char b[1]; }; @@ -1647,6 +1653,18 @@ static void invoke_open(void *data) d->result_ok = status; } +static void invoke_fadvise(void *data) +{ + struct t_data *d = (struct t_data *) data; + int fd = (int) d->fd; + off_t offset = (off_t) d->c.fadvise.offset; + off_t length = (off_t) d->c.fadvise.length; + int advise = (int) d->c.fadvise.advise; + + d->again = 0; + d->result_ok = efile_fadvise(&d->errInfo, fd, offset, length, advise); +} + static void free_readdir(void *data) { struct t_data *d = (struct t_data *) data; @@ -1936,6 +1954,7 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data) case FILE_SYMLINK: case FILE_RENAME: case FILE_WRITE_INFO: + case FILE_FADVISE: reply(desc, d->result_ok, &d->errInfo); free_data(data); break; @@ -2355,6 +2374,21 @@ file_output(ErlDrvData e, char* buf, int count) goto done; } + case FILE_FADVISE: + { + d = EF_SAFE_ALLOC(sizeof(struct t_data)); + + d->fd = fd; + d->command = command; + d->invoke = invoke_fadvise; + d->free = free_data; + d->level = 2; + d->c.fadvise.offset = get_int64((uchar*) buf); + d->c.fadvise.length = get_int64(((uchar*) buf) + sizeof(Sint64)); + d->c.fadvise.advise = get_int32(((uchar*) buf) + 2 * sizeof(Sint64)); + goto done; + } + } /* diff --git a/erts/emulator/drivers/common/erl_efile.h b/erts/emulator/drivers/common/erl_efile.h index 6821a0e2ee..61684af6c9 100644 --- a/erts/emulator/drivers/common/erl_efile.h +++ b/erts/emulator/drivers/common/erl_efile.h @@ -151,3 +151,5 @@ int efile_altname(Efile_error* errInfo, char *name, int efile_link(Efile_error* errInfo, char* old, char* new); int efile_symlink(Efile_error* errInfo, char* old, char* new); int efile_may_openfile(Efile_error* errInfo, char *name); +int efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length, + int advise); 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. diff --git a/erts/emulator/drivers/unix/unix_efile.c b/erts/emulator/drivers/unix/unix_efile.c index 0cece76221..ea016526ef 100644 --- a/erts/emulator/drivers/unix/unix_efile.c +++ b/erts/emulator/drivers/unix/unix_efile.c @@ -1448,3 +1448,14 @@ efile_symlink(Efile_error* errInfo, char* old, char* new) return check_error(symlink(old, new), errInfo); #endif } + +int +efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset, + Sint64 length, int advise) +{ +#ifdef HAVE_POSIX_FADVISE + return check_error(posix_fadvise(fd, offset, length, advise), errInfo); +#else + return check_error(0, errInfo); +#endif +} diff --git a/erts/emulator/drivers/win32/win_efile.c b/erts/emulator/drivers/win32/win_efile.c index cdf3bb424c..06850b4945 100644 --- a/erts/emulator/drivers/win32/win_efile.c +++ b/erts/emulator/drivers/win32/win_efile.c @@ -1433,3 +1433,12 @@ efile_symlink(Efile_error* errInfo, char* old, char* new) errno = ENOTSUP; return check_error(-1, errInfo); } + +int +efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset, + Sint64 length, int advise) +{ + /* posix_fadvise is not available on Windows, do nothing */ + errno = ERROR_SUCCESS; + return check_error(0, errInfo); +} diff --git a/erts/preloaded/src/prim_file.erl b/erts/preloaded/src/prim_file.erl index 53c741e66e..e9df5752ab 100644 --- a/erts/preloaded/src/prim_file.erl +++ b/erts/preloaded/src/prim_file.erl @@ -25,7 +25,7 @@ %%% Interface towards a single file's contents. Uses ?FD_DRV. %% Generic file contents operations --export([open/2, close/1, datasync/1, sync/1, position/2, truncate/1, +-export([open/2, close/1, datasync/1, sync/1, advise/4, position/2, truncate/1, write/2, pwrite/2, pwrite/3, read/2, read_line/1, pread/2, pread/3, copy/3]). %% Specialized file operations @@ -97,6 +97,7 @@ -define(FILE_ALTNAME, 28). -define(FILE_READ_LINE, 29). -define(FILE_FDATASYNC, 30). +-define(FILE_ADVISE, 31). %% Driver responses -define(FILE_RESP_OK, 0). @@ -131,6 +132,13 @@ %% IPREAD variants -define(IPREAD_S32BU_P32BU, 0). +%% POSIX file advises +-define(POSIX_FADV_NORMAL, 0). +-define(POSIX_FADV_RANDOM, 1). +-define(POSIX_FADV_SEQUENTIAL, 2). +-define(POSIX_FADV_WILLNEED, 3). +-define(POSIX_FADV_DONTNEED, 4). +-define(POSIX_FADV_NOREUSE, 5). %%%----------------------------------------------------------------- @@ -221,7 +229,35 @@ close(#file_descriptor{module = ?MODULE, data = {Port, _}}) -> close(Port) when is_port(Port) -> drv_close(Port). +-define(ADVISE(Offs, Len, Adv), + <>). +%% Returns {error, Reason} | ok. +advise(#file_descriptor{module = ?MODULE, data = {Port, _}}, + Offset, Length, Advise) -> + case Advise of + normal -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_NORMAL), + drv_command(Port, Cmd); + random -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_RANDOM), + drv_command(Port, Cmd); + sequential -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_SEQUENTIAL), + drv_command(Port, Cmd); + will_need -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_WILLNEED), + drv_command(Port, Cmd); + dont_need -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_DONTNEED), + drv_command(Port, Cmd); + no_reuse -> + Cmd = ?ADVISE(Offset, Length, ?POSIX_FADV_NOREUSE), + drv_command(Port, Cmd); + _ -> + {error, einval} + end. %% Returns {error, Reason} | ok. write(#file_descriptor{module = ?MODULE, data = {Port, _}}, Bytes) -> -- cgit v1.2.3