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[S390] vmlogrdr: purge after recording is switched off

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If automatic purge is enabled for a vmlogrdr device, old records are
purged before an IUCV recording service is switched on or off. If z/VM
generates a large number of records between purging and switching the
recording service off, these records remain queued, and may have a
negative performance impact on the z/VM system. To avoid this problem,
we need to purge the records after recording is switched off.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Stefan Weinhuber 2010-11-10 10:05:54 +01:00 committed by Martin Schwidefsky
parent 16d2ce271c
commit ca768b6631
1 changed files with 24 additions and 12 deletions
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36
drivers/s390/char/vmlogrdr.c
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@ -249,27 +249,25 @@ static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
char cp_command[80];
char cp_response[160];
char *onoff, *qid_string;
int rc;
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
onoff = ((action == 1) ? "ON" : "OFF");
onoff = ((action == 1) ? "ON" : "OFF");
qid_string = ((recording_class_AB == 1) ? " QID * " : "");
/*
/*
* The recording commands needs to be called with option QID
* for guests that have previlege classes A or B.
* Purging has to be done as separate step, because recording
* can't be switched on as long as records are on the queue.
* Doing both at the same time doesn't work.
*/
if (purge) {
if (purge && (action == 1)) {
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE %s",
logptr->recording_name,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
}
@ -279,19 +277,33 @@ static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
logptr->recording_name,
onoff,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
/* The recording command will usually answer with 'Command complete'
* on success, but when the specific service was never connected
* before then there might be an additional informational message
* 'HCPCRC8072I Recording entry not found' before the
* 'Command complete'. So I use strstr rather then the strncmp.
* 'Command complete'. So I use strstr rather then the strncmp.
*/
if (strstr(cp_response,"Command complete"))
return 0;
rc = 0;
else
return -EIO;
rc = -EIO;
/*
* If we turn recording off, we have to purge any remaining records
* afterwards, as a large number of queued records may impact z/VM
* performance.
*/
if (purge && (action == 0)) {
memset(cp_command, 0x00, sizeof(cp_command));
memset(cp_response, 0x00, sizeof(cp_response));
snprintf(cp_command, sizeof(cp_command),
"RECORDING %s PURGE %s",
logptr->recording_name,
qid_string);
cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
}
return rc;
}