Messages in this thread Patch in this message | | | Date | Sat, 9 Aug 2003 11:48:30 +1000 | Subject | Re: [PATCH] 2.4: Restore current->files in flush_old_exec | From | Herbert Xu <> |
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On Sat, Aug 09, 2003 at 11:11:16AM +1000, herbert wrote: > > At this point, I believe the unshare_files stuff should be fine from > a correctness point of view. However, there is still a performance > problem as every ELF exec call ends up dupliating the files structure > as well as walking through all file locks.
Here is the patch that ensures files is only duplicated when necessary. -- Debian GNU/Linux 3.0 is out! ( http://www.debian.org/ ) Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt --- kernel-source-2.4/fs/binfmt_elf.c.orig 2003-08-09 11:28:18.000000000 +1000 +++ kernel-source-2.4/fs/binfmt_elf.c 2003-08-09 11:32:13.000000000 +1000 @@ -480,6 +480,10 @@ files = current->files; /* Refcounted so ok */ if(unshare_files() < 0) goto out_free_ph; + if (files == current->files) { + put_files_struct(files); + files = NULL; + } /* exec will make our files private anyway, but for the a.out loader stuff we need to do it earlier */ @@ -602,8 +606,10 @@ goto out_free_dentry; /* Discard our unneeded old files struct */ - steal_locks(files, current->files); - put_files_struct(files); + if (files) { + steal_locks(files, current->files); + put_files_struct(files); + } /* OK, This is the point of no return */ current->mm->start_data = 0; @@ -811,9 +817,11 @@ out_free_file: sys_close(elf_exec_fileno); out_free_fh: - ftmp = current->files; - current->files = files; - put_files_struct(ftmp); + if (files) { + ftmp = current->files; + current->files = files; + put_files_struct(ftmp); + } out_free_ph: kfree(elf_phdata); goto out; | |