32c5483a8a
Lots of the dir code now goes through switches to determine what is the correct on-disk format to parse. It generally involves a "xfs_sbversion_hasfoo" check, deferencing the superblock version and feature fields and hence touching several cache lines per operation in the process. Some operations do multiple checks because they nest conditional operations and they don't pass the information in a direct fashion between each other. Hence, add an ops vector to the xfs_inode structure that is configured when the inode is initialised to point to all the correct decode and encoding operations. This will significantly reduce the branchiness and cacheline footprint of the directory object decoding and encoding. This is the first patch in a series of conversion patches. It will introduce the ops structure, the setup of it and add the first operation to the vector. Subsequent patches will convert directory ops one at a time to keep the changes simple and obvious. Just this patch shows the benefit of such an approach on code size. Just converting the two shortform dir operations as this patch does decreases the built binary size by ~1500 bytes: $ size fs/xfs/xfs.o.orig fs/xfs/xfs.o.p1 text data bss dec hex filename 794490 96802 1096 892388 d9de4 fs/xfs/xfs.o.orig 792986 96802 1096 890884 d9804 fs/xfs/xfs.o.p1 $ That's a significant decrease in the instruction cache footprint of the directory code for such a simple change, and indicates that this approach is definitely worth pursuing further. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
/*
|
|
* Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
|
|
* Copyright (c) 2013 Red Hat, Inc.
|
|
* All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it would be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#include "xfs.h"
|
|
#include "xfs_fs.h"
|
|
#include "xfs_format.h"
|
|
#include "xfs_log_format.h"
|
|
#include "xfs_trans_resv.h"
|
|
#include "xfs_sb.h"
|
|
#include "xfs_ag.h"
|
|
#include "xfs_mount.h"
|
|
#include "xfs_da_format.h"
|
|
#include "xfs_inode.h"
|
|
#include "xfs_dir2.h"
|
|
|
|
|
|
static int
|
|
xfs_dir2_sf_entsize(
|
|
struct xfs_dir2_sf_hdr *hdr,
|
|
int len)
|
|
{
|
|
int count = sizeof(struct xfs_dir2_sf_entry); /* namelen + offset */
|
|
|
|
count += len; /* name */
|
|
count += hdr->i8count ? sizeof(xfs_dir2_ino8_t) :
|
|
sizeof(xfs_dir2_ino4_t); /* ino # */
|
|
return count;
|
|
}
|
|
|
|
static int
|
|
xfs_dir3_sf_entsize(
|
|
struct xfs_dir2_sf_hdr *hdr,
|
|
int len)
|
|
{
|
|
return xfs_dir2_sf_entsize(hdr, len) + sizeof(__uint8_t);
|
|
}
|
|
|
|
static struct xfs_dir2_sf_entry *
|
|
xfs_dir2_sf_nextentry(
|
|
struct xfs_dir2_sf_hdr *hdr,
|
|
struct xfs_dir2_sf_entry *sfep)
|
|
{
|
|
return (struct xfs_dir2_sf_entry *)
|
|
((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
|
|
}
|
|
|
|
static struct xfs_dir2_sf_entry *
|
|
xfs_dir3_sf_nextentry(
|
|
struct xfs_dir2_sf_hdr *hdr,
|
|
struct xfs_dir2_sf_entry *sfep)
|
|
{
|
|
return (struct xfs_dir2_sf_entry *)
|
|
((char *)sfep + xfs_dir3_sf_entsize(hdr, sfep->namelen));
|
|
}
|
|
|
|
|
|
const struct xfs_dir_ops xfs_dir2_ops = {
|
|
.sf_entsize = xfs_dir2_sf_entsize,
|
|
.sf_nextentry = xfs_dir2_sf_nextentry,
|
|
};
|
|
|
|
const struct xfs_dir_ops xfs_dir2_ftype_ops = {
|
|
.sf_entsize = xfs_dir3_sf_entsize,
|
|
.sf_nextentry = xfs_dir3_sf_nextentry,
|
|
};
|
|
|
|
const struct xfs_dir_ops xfs_dir3_ops = {
|
|
.sf_entsize = xfs_dir3_sf_entsize,
|
|
.sf_nextentry = xfs_dir3_sf_nextentry,
|
|
};
|