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| author | Amit Arora <aarora@in.ibm.com> | 2007-07-17 21:42:44 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2007-07-17 21:42:44 -0400 |
| commit | 97ac73506c0ba93f30239bb57b4cfc5d73e68a62 (patch) | |
| tree | 4d02848d6c792a70b413deadcaffd7bf8c8d61de /include/asm-powerpc/unistd.h | |
| parent | cb32da0416b823b7f4b65e7e85d6cba16ca4d1e1 (diff) | |
sys_fallocate() implementation on i386, x86_64 and powerpc
fallocate() is a new system call being proposed here which will allow
applications to preallocate space to any file(s) in a file system.
Each file system implementation that wants to use this feature will need
to support an inode operation called ->fallocate().
Applications can use this feature to avoid fragmentation to certain
level and thus get faster access speed. With preallocation, applications
also get a guarantee of space for particular file(s) - even if later the
the system becomes full.
Currently, glibc provides an interface called posix_fallocate() which
can be used for similar cause. Though this has the advantage of working
on all file systems, but it is quite slow (since it writes zeroes to
each block that has to be preallocated). Without a doubt, file systems
can do this more efficiently within the kernel, by implementing
the proposed fallocate() system call. It is expected that
posix_fallocate() will be modified to call this new system call first
and incase the kernel/filesystem does not implement it, it should fall
back to the current implementation of writing zeroes to the new blocks.
ToDos:
1. Implementation on other architectures (other than i386, x86_64,
and ppc). Patches for s390(x) and ia64 are already available from
previous posts, but it was decided that they should be added later
once fallocate is in the mainline. Hence not including those patches
in this take.
2. Changes to glibc,
a) to support fallocate() system call
b) to make posix_fallocate() and posix_fallocate64() call fallocate()
Signed-off-by: Amit Arora <aarora@in.ibm.com>
Diffstat (limited to 'include/asm-powerpc/unistd.h')
| -rw-r--r-- | include/asm-powerpc/unistd.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h index f71c6061f1e..97d82b6a940 100644 --- a/include/asm-powerpc/unistd.h +++ b/include/asm-powerpc/unistd.h @@ -331,10 +331,11 @@ #define __NR_timerfd 306 #define __NR_eventfd 307 #define __NR_sync_file_range2 308 +#define __NR_fallocate 309 #ifdef __KERNEL__ -#define __NR_syscalls 309 +#define __NR_syscalls 310 #define __NR__exit __NR_exit #define NR_syscalls __NR_syscalls |