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| author | delphij <delphij@FreeBSD.org> | 2009-09-28 16:59:47 +0000 |
|---|---|---|
| committer | delphij <delphij@FreeBSD.org> | 2009-09-28 16:59:47 +0000 |
| commit | 79f2f8c774b48d4ef62f92d4a09e80af3ceaca7c (patch) | |
| tree | 1cca7c0ea10e2ad0213a1d75a2c8a8fe0061f4d4 /sys/sys/fcntl.h | |
| parent | fd5f08e3e82b6caa8a7fff6a32c9e56b9212003e (diff) | |
| download | FreeBSD-src-79f2f8c774b48d4ef62f92d4a09e80af3ceaca7c.zip FreeBSD-src-79f2f8c774b48d4ef62f92d4a09e80af3ceaca7c.tar.gz | |
Add two new fcntls to enable/disable read-ahead:
- F_READAHEAD: specify the amount for sequential access. The amount is
specified in bytes and is rounded up to nearest block size.
- F_RDAHEAD: Darwin compatible version that use 128KB as the sequential
access size.
A third argument of zero disables the read-ahead behavior.
Please note that the read-ahead amount is also constrainted by sysctl
variable, vfs.read_max, which may need to be raised in order to better
utilize this feature.
Thanks Igor Sysoev for proposing the feature and submitting the original
version, and kib@ for his valuable comments.
Submitted by: Igor Sysoev <is rambler-co ru>
Reviewed by: kib@
MFC after: 1 month
Diffstat (limited to 'sys/sys/fcntl.h')
| -rw-r--r-- | sys/sys/fcntl.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/sys/sys/fcntl.h b/sys/sys/fcntl.h index 893bbcd..ef394a3 100644 --- a/sys/sys/fcntl.h +++ b/sys/sys/fcntl.h @@ -140,7 +140,7 @@ typedef __pid_t pid_t; /* bits to save after open */ #define FMASK (FREAD|FWRITE|FAPPEND|FASYNC|FFSYNC|FNONBLOCK|O_DIRECT|FEXEC) /* bits settable by fcntl(F_SETFL, ...) */ -#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|O_DIRECT) +#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|FRDAHEAD|O_DIRECT) #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) @@ -151,7 +151,8 @@ typedef __pid_t pid_t; */ #define FPOSIXSHM O_NOFOLLOW #undef FCNTLFLAGS -#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|FPOSIXSHM|O_DIRECT) +#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|FPOSIXSHM|FRDAHEAD| \ + O_DIRECT) #endif #endif @@ -176,6 +177,8 @@ typedef __pid_t pid_t; * different meaning for fcntl(2). */ #if __BSD_VISIBLE +/* Read ahead */ +#define FRDAHEAD O_CREAT #endif /* Defined by POSIX Extended API Set Part 2 */ @@ -218,6 +221,8 @@ typedef __pid_t pid_t; #define F_SETLK 12 /* set record locking information */ #define F_SETLKW 13 /* F_SETLK; wait if blocked */ #define F_SETLK_REMOTE 14 /* debugging support for remote locks */ +#define F_READAHEAD 15 /* read ahead */ +#define F_RDAHEAD 16 /* Darwin compatible read ahead */ /* file descriptor flags (F_GETFD, F_SETFD) */ #define FD_CLOEXEC 1 /* close-on-exec flag */ |
