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smb3: add way to control slow response threshold for logging and stats 

/proc/fs/cifs/Stats when CONFIG_CIFS_STATS2 is enabled logs 'slow'
responses, but depending on the server you are debugging a
one second timeout may be too fast, so allow setting it to
a larger number of seconds via new module parameter

/sys/module/cifs/parameters/slow_rsp_threshold

or via modprobe:

slow_rsp_threshold:Amount of time (in seconds) to wait before
logging that a response is delayed.
Default: 1 (if set to 0 disables msg). (uint)

Recommended values are 0 (disabled) to 32767 (9 hours) with
the default remaining as 1 second.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
hifive-unleashed-5.1
Steve French 2018-09-18 14:05:18 -05:00
parent 1c3a13a38a
commit 00778e2294
3 changed files with 26 additions and 3 deletions
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13
fs/cifs/cifsfs.c
View File

@ -81,6 +81,14 @@ module_param(cifs_max_pending, uint, 0444);
MODULE_PARM_DESC(cifs_max_pending, "Simultaneous requests to server for "
"CIFS/SMB1 dialect (N/A for SMB3) "
"Default: 32767 Range: 2 to 32767.");
#ifdef CONFIG_CIFS_STATS2
unsigned int slow_rsp_threshold = 1;
module_param(slow_rsp_threshold, uint, 0644);
MODULE_PARM_DESC(slow_rsp_threshold, "Amount of time (in seconds) to wait "
"before logging that a response is delayed. "
"Default: 1 (if set to 0 disables msg).");
#endif /* STATS2 */
module_param(enable_oplocks, bool, 0644);
MODULE_PARM_DESC(enable_oplocks, "Enable or disable oplocks. Default: y/Y/1");
@ -1418,6 +1426,11 @@ init_cifs(void)
#ifdef CONFIG_CIFS_STATS2
atomic_set(&totBufAllocCount, 0);
atomic_set(&totSmBufAllocCount, 0);
if (slow_rsp_threshold < 1)
cifs_dbg(FYI, "slow_response_threshold msgs disabled\n");
else if (slow_rsp_threshold > 32767)
cifs_dbg(VFS,
"slow response threshold set higher than recommended (0 to 32767)\n");
#endif /* CONFIG_CIFS_STATS2 */
atomic_set(&midCount, 0);

1
fs/cifs/cifsglob.h
View File

@ -1715,6 +1715,7 @@ GLOBAL_EXTERN atomic_t bufAllocCount; /* current number allocated */
#ifdef CONFIG_CIFS_STATS2
GLOBAL_EXTERN atomic_t totBufAllocCount; /* total allocated over all time */
GLOBAL_EXTERN atomic_t totSmBufAllocCount;
extern unsigned int slow_rsp_threshold; /* number of secs before logging */
#endif
GLOBAL_EXTERN atomic_t smBufAllocCount;
GLOBAL_EXTERN atomic_t midCount;

15
fs/cifs/transport.c
View File

@ -113,9 +113,18 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
cifs_small_buf_release(midEntry->resp_buf);
#ifdef CONFIG_CIFS_STATS2
now = jiffies;
/* commands taking longer than one second are indications that
something is wrong, unless it is quite a slow link or server */
if (time_after(now, midEntry->when_alloc + HZ) &&
/*
* commands taking longer than one second (default) can be indications
* that something is wrong, unless it is quite a slow link or a very
* busy server. Note that this calc is unlikely or impossible to wrap
* as long as slow_rsp_threshold is not set way above recommended max
* value (32767 ie 9 hours) and is generally harmless even if wrong
* since only affects debug counters - so leaving the calc as simple
* comparison rather than doing multiple conversions and overflow
* checks
*/
if ((slow_rsp_threshold != 0) &&
time_after(now, midEntry->when_alloc + (slow_rsp_threshold * HZ)) &&
(midEntry->command != command)) {
/* smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command */
if ((le16_to_cpu(midEntry->command) < NUMBER_OF_SMB2_COMMANDS) &&