[Samba] Performance issue on AIX when deleting files in
adirectory with a large number of files
Jeremy Allison
jra at samba.org
Fri May 12 23:06:08 GMT 2006
On Thu, May 11, 2006 at 04:06:37PM -0700, Jeremy Allison wrote:
> On Thu, May 11, 2006 at 03:54:17PM -0700, Jeremy Allison wrote:
> >
> > Do you see the change notify replies happening followed by the
> > change notify setups ? I bet I know what it is....
> >
> > Because AIX doesn't have kernel change notify when the change
> > notify setup comes (which happens after every delete) it causes a
> > directory rescan at that point - after *each* delete !
>
> I think I can code around this. The key is to ensure that
> setting "change notify timeout" to zero turns off change
> notify except for renames and deletes. Also make it a per-share
> parameter so it can be set to zero for "large" directories...
>
> Give me a day or so on this.
Ok - here is the patch. Bill - if you could test this on
AIX by setting the (now per-share) parameter :
"change notify timeout = 0"
on the share definition that holds a large number of files,
you might find a speed up. I can see the effect it has here
when I disable the kernel and FAM based change notify.
Jeremy.
-------------- next part --------------
Index: smbd/service.c
===================================================================
--- smbd/service.c (revision 15550)
+++ smbd/service.c (working copy)
@@ -930,6 +930,9 @@
dbgtext( "(pid %d)\n", (int)sys_getpid() );
}
+ /* Setup the minimum value for a change notify wait time (seconds). */
+ set_change_notify_timeout(lp_change_notify_timeout(snum));
+
/* we've finished with the user stuff - go back to root */
change_to_root_user();
return(conn);
Index: smbd/notify.c
===================================================================
--- smbd/notify.c (revision 15550)
+++ smbd/notify.c (working copy)
@@ -135,9 +135,21 @@
}
/****************************************************************************
- Return true if there are pending change notifies.
+ Set the current change notify timeout to the lowest value across all service
+ values.
****************************************************************************/
+void set_change_notify_timeout(int val)
+{
+ if (val > 0) {
+ cnotify->select_time = MIN(cnotify->select_time, val);
+ }
+}
+
+/****************************************************************************
+ Longest time to sleep for before doing a change notify scan.
+****************************************************************************/
+
int change_notify_timeout(void)
{
return cnotify->select_time;
Index: smbd/notify_hash.c
===================================================================
--- smbd/notify_hash.c (revision 15550)
+++ smbd/notify_hash.c (working copy)
@@ -81,6 +81,11 @@
return True;
}
+ if (lp_change_notify_timeout(SNUM(conn)) <= 0) {
+ /* It change notify timeout has been disabled, never scan the directory. */
+ return True;
+ }
+
/*
* If we are to watch for changes that are only stored
* in inodes of files, not in the directory inode, we must
@@ -179,10 +184,18 @@
{
struct change_data *data = (struct change_data *)datap;
struct change_data data2;
+ int cnto = lp_change_notify_timeout(SNUM(conn));
- if (t && t < data->last_check_time + lp_change_notify_timeout())
+ if (t && cnto <= 0) {
+ /* Change notify turned off on this share.
+ * Only scan when (t==0) - we think something changed. */
return False;
+ }
+ if (t && t < data->last_check_time + cnto) {
+ return False;
+ }
+
if (!change_to_user(conn,vuid))
return True;
if (!set_current_service(conn,FLAG_CASELESS_PATHNAMES,True)) {
@@ -201,8 +214,9 @@
return True;
}
- if (t)
+ if (t) {
data->last_check_time = t;
+ }
change_to_root_user();
@@ -229,7 +243,7 @@
cnotify.register_notify = hash_register_notify;
cnotify.check_notify = hash_check_notify;
cnotify.remove_notify = hash_remove_notify;
- cnotify.select_time = lp_change_notify_timeout();
+ cnotify.select_time = 60; /* Start with 1 minute default. */
cnotify.notification_fd = -1;
return &cnotify;
Index: param/loadparm.c
===================================================================
--- param/loadparm.c (revision 15550)
+++ param/loadparm.c (working copy)
@@ -220,7 +220,6 @@
int lm_interval;
int announce_as; /* This is initialised in init_globals */
int machine_password_timeout;
- int change_notify_timeout;
int map_to_guest;
int oplock_break_wait_time;
int winbind_cache_time;
@@ -449,6 +448,7 @@
int iAioReadSize;
int iAioWriteSize;
int iMap_readonly;
+ int ichange_notify_timeout;
param_opt_struct *param_opt;
char dummy[3]; /* for alignment */
@@ -587,6 +587,7 @@
0, /* iAioReadSize */
0, /* iAioWriteSize */
MAP_READONLY_YES, /* iMap_readonly */
+ 60, /* ichange_notify_timeout = 1 minute default. */
NULL, /* Parametric options */
@@ -996,7 +997,7 @@
{N_("Tuning Options"), P_SEP, P_SEPARATOR},
{"block size", P_INTEGER, P_LOCAL, &sDefault.iBlock_size, NULL, NULL, FLAG_ADVANCED | FLAG_SHARE | FLAG_GLOBAL},
- {"change notify timeout", P_INTEGER, P_GLOBAL, &Globals.change_notify_timeout, NULL, NULL, FLAG_ADVANCED},
+ {"change notify timeout", P_INTEGER, P_LOCAL, &sDefault.ichange_notify_timeout, NULL, NULL, FLAG_ADVANCED},
{"deadtime", P_INTEGER, P_GLOBAL, &Globals.deadtime, NULL, NULL, FLAG_ADVANCED},
{"getwd cache", P_BOOL, P_GLOBAL, &use_getwd_cache, NULL, NULL, FLAG_ADVANCED},
{"keepalive", P_INTEGER, P_GLOBAL, &keepalive, NULL, NULL, FLAG_ADVANCED},
@@ -1507,7 +1508,6 @@
Globals.max_wins_ttl = 60 * 60 * 24 * 6; /* 6 days default. */
Globals.min_wins_ttl = 60 * 60 * 6; /* 6 hours default. */
Globals.machine_password_timeout = 60 * 60 * 24 * 7; /* 7 days default. */
- Globals.change_notify_timeout = 60; /* 1 minute default. */
Globals.bKernelChangeNotify = True; /* On if we have it. */
Globals.bFamChangeNotify = True; /* On if we have it. */
Globals.lm_announce = 2; /* = Auto: send only if LM clients found */
@@ -1934,7 +1934,6 @@
FN_GLOBAL_INTEGER(lp_lm_announce, &Globals.lm_announce)
FN_GLOBAL_INTEGER(lp_lm_interval, &Globals.lm_interval)
FN_GLOBAL_INTEGER(lp_machine_password_timeout, &Globals.machine_password_timeout)
-FN_GLOBAL_INTEGER(lp_change_notify_timeout, &Globals.change_notify_timeout)
FN_GLOBAL_INTEGER(lp_map_to_guest, &Globals.map_to_guest)
FN_GLOBAL_INTEGER(lp_oplock_break_wait_time, &Globals.oplock_break_wait_time)
FN_GLOBAL_INTEGER(lp_lock_spin_count, &Globals.iLockSpinCount)
@@ -2066,6 +2065,7 @@
FN_LOCAL_INTEGER(lp_aio_read_size, iAioReadSize)
FN_LOCAL_INTEGER(lp_aio_write_size, iAioWriteSize)
FN_LOCAL_INTEGER(lp_map_readonly, iMap_readonly)
+FN_LOCAL_INTEGER(lp_change_notify_timeout, ichange_notify_timeout)
FN_LOCAL_CHAR(lp_magicchar, magic_char)
FN_GLOBAL_INTEGER(lp_winbind_cache_time, &Globals.winbind_cache_time)
FN_GLOBAL_LIST(lp_winbind_nss_info, &Globals.szWinbindNssInfo)
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