lkml.org 
[lkml]   [2006]   [Jan]   [7]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateSat, 07 Jan 2006 00:02:32 -0800
FromUlrich Drepper <>
SubjectRe: [PATCH 0/3] updated *at function patch
Andrew Morton wrote:
> We don't have changelogs for these patches.  Apart from the usual
> what-it-does and how-it-does it I'd really like to be reminded of the
> "why".  Adding a bunch of stuff to the core kernel codepaths needs to have
> a good reason and I've forgotten your rationale.

This is the intro from the first set of patches I sent (I adjusted it
for the additional syscalls):

====
Here is a series of patches which introduce in total 13 new system calls
which take a file descriptor/filename pair instead of a single file
name.  These functions, openat etc, have been discussed on numerous
occasions.  They are needed to implement race-free filesystem traversal,
they are necessary to implement a virtual per-thread current working
directory (think multi-threaded backup software), etc.
We have in glibc today implementations of the interfaces which use the
/proc/self/fd magic.  But this code is rather expensive.  Here are some
results (similar to what Jim Meyering posted before).

The test creates a deep directory hierarchy on a tmpfs filesystem.  Then
rm -fr is used to remove all directories.  Without syscall support I get
this:

real    0m31.921s
user    0m0.688s
sys     0m31.234s

With syscall support the results are much better:

real    0m20.699s
user    0m0.536s
sys     0m20.149s
=====


> We'll need Signed-off_by:'s for all these patches.

I'm not sure how you want to handle this.  I don't particularly want to
resent all of them just for this purpose.

[PATCH 1/3] updated *at function patch

Signed-off-by: Ulrich Drepper <drepper@redhat.com>

[PATCH 2/3] updated *at function patch

Signed-off-by: Ulrich Drepper <drepper@redhat.com>

[PATCH 3/3] updated *at function patch

Signed-off-by: Ulrich Drepper <drepper@redhat.com>


-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖

[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2006-01-07 08:05    [from the cache]
©2003-2008