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linux-2.6/fs/xfs/xfs_error.c
Dave Chinner c76febef57 xfs: only run xfs_error_test if error injection is active
Recent tests writing lots of small files showed the flusher thread
being CPU bound and taking a long time to do allocations on a debug
kernel. perf showed this as the prime reason:

             samples  pcnt function                    DSO
             _______ _____ ___________________________ _________________

           224648.00 36.8% xfs_error_test              [kernel.kallsyms]
            86045.00 14.1% xfs_btree_check_sblock      [kernel.kallsyms]
            39778.00  6.5% prandom32                   [kernel.kallsyms]
            37436.00  6.1% xfs_btree_increment         [kernel.kallsyms]
            29278.00  4.8% xfs_btree_get_rec           [kernel.kallsyms]
            27717.00  4.5% random32                    [kernel.kallsyms]

Walking btree blocks during allocation checking them requires each
block (a cache hit, so no I/O) call xfs_error_test(), which then
does a random32() call as the first operation.  IOWs, ~50% of the
CPU is being consumed just testing whether we need to inject an
error, even though error injection is not active.

Kill this overhead when error injection is not active by adding a
global counter of active error traps and only calling into
xfs_error_test when fault injection is active.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-12-01 07:40:20 -06:00

219 lines
4.6 KiB
C

/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, 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_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_utils.h"
#include "xfs_error.h"
#ifdef DEBUG
int xfs_etrap[XFS_ERROR_NTRAP] = {
0,
};
int
xfs_error_trap(int e)
{
int i;
if (!e)
return 0;
for (i = 0; i < XFS_ERROR_NTRAP; i++) {
if (xfs_etrap[i] == 0)
break;
if (e != xfs_etrap[i])
continue;
cmn_err(CE_NOTE, "xfs_error_trap: error %d", e);
BUG();
break;
}
return e;
}
int xfs_etest[XFS_NUM_INJECT_ERROR];
int64_t xfs_etest_fsid[XFS_NUM_INJECT_ERROR];
char * xfs_etest_fsname[XFS_NUM_INJECT_ERROR];
int xfs_error_test_active;
int
xfs_error_test(int error_tag, int *fsidp, char *expression,
int line, char *file, unsigned long randfactor)
{
int i;
int64_t fsid;
if (random32() % randfactor)
return 0;
memcpy(&fsid, fsidp, sizeof(xfs_fsid_t));
for (i = 0; i < XFS_NUM_INJECT_ERROR; i++) {
if (xfs_etest[i] == error_tag && xfs_etest_fsid[i] == fsid) {
cmn_err(CE_WARN,
"Injecting error (%s) at file %s, line %d, on filesystem \"%s\"",
expression, file, line, xfs_etest_fsname[i]);
return 1;
}
}
return 0;
}
int
xfs_errortag_add(int error_tag, xfs_mount_t *mp)
{
int i;
int len;
int64_t fsid;
memcpy(&fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t));
for (i = 0; i < XFS_NUM_INJECT_ERROR; i++) {
if (xfs_etest_fsid[i] == fsid && xfs_etest[i] == error_tag) {
cmn_err(CE_WARN, "XFS error tag #%d on", error_tag);
return 0;
}
}
for (i = 0; i < XFS_NUM_INJECT_ERROR; i++) {
if (xfs_etest[i] == 0) {
cmn_err(CE_WARN, "Turned on XFS error tag #%d",
error_tag);
xfs_etest[i] = error_tag;
xfs_etest_fsid[i] = fsid;
len = strlen(mp->m_fsname);
xfs_etest_fsname[i] = kmem_alloc(len + 1, KM_SLEEP);
strcpy(xfs_etest_fsname[i], mp->m_fsname);
xfs_error_test_active++;
return 0;
}
}
cmn_err(CE_WARN, "error tag overflow, too many turned on");
return 1;
}
int
xfs_errortag_clearall(xfs_mount_t *mp, int loud)
{
int64_t fsid;
int cleared = 0;
int i;
memcpy(&fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t));
for (i = 0; i < XFS_NUM_INJECT_ERROR; i++) {
if ((fsid == 0LL || xfs_etest_fsid[i] == fsid) &&
xfs_etest[i] != 0) {
cleared = 1;
cmn_err(CE_WARN, "Clearing XFS error tag #%d",
xfs_etest[i]);
xfs_etest[i] = 0;
xfs_etest_fsid[i] = 0LL;
kmem_free(xfs_etest_fsname[i]);
xfs_etest_fsname[i] = NULL;
xfs_error_test_active--;
}
}
if (loud || cleared)
cmn_err(CE_WARN,
"Cleared all XFS error tags for filesystem \"%s\"",
mp->m_fsname);
return 0;
}
#endif /* DEBUG */
void
xfs_fs_cmn_err(int level, xfs_mount_t *mp, char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
xfs_fs_vcmn_err(level, mp, fmt, ap);
va_end(ap);
}
void
xfs_cmn_err(int panic_tag, int level, xfs_mount_t *mp, char *fmt, ...)
{
va_list ap;
#ifdef DEBUG
xfs_panic_mask |= (XFS_PTAG_SHUTDOWN_CORRUPT | XFS_PTAG_LOGRES);
#endif
if (xfs_panic_mask && (xfs_panic_mask & panic_tag)
&& (level & CE_ALERT)) {
level &= ~CE_ALERT;
level |= CE_PANIC;
cmn_err(CE_ALERT, "XFS: Transforming an alert into a BUG.");
}
va_start(ap, fmt);
xfs_fs_vcmn_err(level, mp, fmt, ap);
va_end(ap);
}
void
xfs_error_report(
const char *tag,
int level,
struct xfs_mount *mp,
const char *filename,
int linenum,
inst_t *ra)
{
if (level <= xfs_error_level) {
xfs_cmn_err(XFS_PTAG_ERROR_REPORT,
CE_ALERT, mp,
"XFS internal error %s at line %d of file %s. Caller 0x%p\n",
tag, linenum, filename, ra);
xfs_stack_trace();
}
}
void
xfs_corruption_error(
const char *tag,
int level,
struct xfs_mount *mp,
void *p,
const char *filename,
int linenum,
inst_t *ra)
{
if (level <= xfs_error_level)
xfs_hex_dump(p, 16);
xfs_error_report(tag, level, mp, filename, linenum, ra);
}