On Mon, Mar 19, 2018 at 04:01:50PM +0100, Martin Wilck wrote:
> This makes the timeout for "find_multipaths smart" configurable.
> If the timeout has a negative value (default), it's applied only
> to "known" hardware which is either in the hwtable or in a "device" section in
> multipath.conf. For typical non-multipath hardware, which is not in the
> hwtable, a short timeout of 1s is used, so that boot delays caused by
> pointlessly waiting e.g. for SATA devices will be minimal.
>
> It's expected that a "reasonable" timeout value depends less on the storage
> hardware itself but on other properties of the data center such as network
> latencies or distances. find_multipaths_timeout is therefore just a "defaults"
> section setting.
>
I still dislike doing this every time we boot for devices that we aren't
supposed to multipath, although with the reduced timeout for devices
that don't have configs, I don't think that this will be a problem for
most users.
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> libmultipath/config.h | 1 +
> libmultipath/defaults.h | 2 ++
> libmultipath/dict.c | 6 ++++++
> libmultipath/propsel.c | 25 +++++++++++++++++++++++++
> libmultipath/propsel.h | 1 +
> libmultipath/structs.h | 1 +
> multipath/main.c | 13 +++++++++++--
> multipath/multipath.conf.5 | 18 ++++++++++++++++++
> 8 files changed, 65 insertions(+), 2 deletions(-)
>
> diff --git a/libmultipath/config.h b/libmultipath/config.h
> index 21d8e72a2492..72d66018893b 100644
> --- a/libmultipath/config.h
> +++ b/libmultipath/config.h
> @@ -174,6 +174,7 @@ struct config {
> int remove_retries;
> int max_sectors_kb;
> int ghost_delay;
> + int find_multipaths_timeout;
> unsigned int version[3];
>
> char * multipath_dir;
> diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h
> index 690182c368d9..018eb01c1830 100644
> --- a/libmultipath/defaults.h
> +++ b/libmultipath/defaults.h
> @@ -41,6 +41,8 @@
> #define DEFAULT_DISABLE_CHANGED_WWIDS 1
> #define DEFAULT_MAX_SECTORS_KB MAX_SECTORS_KB_UNDEF
> #define DEFAULT_GHOST_DELAY GHOST_DELAY_OFF
> +#define DEFAULT_FIND_MULTIPATHS_TIMEOUT -10
> +#define DEFAULT_UNKNOWN_FIND_MULTIPATHS_TIMEOUT 1
>
> #define DEFAULT_CHECKINT 5
> #define MAX_CHECKINT(a) (a << 2)
> diff --git a/libmultipath/dict.c b/libmultipath/dict.c
> index a952c60a6f98..d59fdc85a9cb 100644
> --- a/libmultipath/dict.c
> +++ b/libmultipath/dict.c
> @@ -484,6 +484,10 @@ declare_hw_snprint(max_sectors_kb, print_nonzero)
> declare_mp_handler(max_sectors_kb, set_int)
> declare_mp_snprint(max_sectors_kb, print_nonzero)
>
> +declare_def_handler(find_multipaths_timeout, set_int)
> +declare_def_snprint_defint(find_multipaths_timeout, print_int,
> + DEFAULT_FIND_MULTIPATHS_TIMEOUT)
> +
> static int
> def_config_dir_handler(struct config *conf, vector strvec)
> {
> @@ -1518,6 +1522,8 @@ init_keywords(vector keywords)
> install_keyword("remove_retries", &def_remove_retries_handler, &snprint_def_remove_retries);
> install_keyword("max_sectors_kb", &def_max_sectors_kb_handler, &snprint_def_max_sectors_kb);
> install_keyword("ghost_delay", &def_ghost_delay_handler, &snprint_def_ghost_delay);
> + install_keyword("find_multipaths_timeout", &def_find_multipaths_timeout_handler,
> + &snprint_def_find_multipaths_timeout);
> __deprecated install_keyword("default_selector", &def_selector_handler, NULL);
> __deprecated install_keyword("default_path_grouping_policy", &def_pgpolicy_handler, NULL);
> __deprecated install_keyword("default_uid_attribute", &def_uid_attribute_handler, NULL);
> diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
> index 58a6a42fe333..87d6865d17e6 100644
> --- a/libmultipath/propsel.c
> +++ b/libmultipath/propsel.c
> @@ -911,3 +911,28 @@ out:
> condlog(3, "%s: ghost_delay = %s %s", mp->alias, buff, origin);
> return 0;
> }
> +
> +int select_find_multipaths_timeout(struct config *conf, struct path *pp)
> +{
> + char *origin;
> +
> + pp_set_conf(find_multipaths_timeout);
> + pp_set_default(find_multipaths_timeout,
> + DEFAULT_FIND_MULTIPATHS_TIMEOUT);
> +out:
> + /*
> + * If configured value is negative, and this "unkown" hardware
> + * (no hwentry), use very small timeout to avoid delays.
> + */
> + if (pp->find_multipaths_timeout < 0) {
> + pp->find_multipaths_timeout = - pp->find_multipaths_timeout;
> + if (!pp->hwe) {
> + pp->find_multipaths_timeout =
> + DEFAULT_UNKNOWN_FIND_MULTIPATHS_TIMEOUT;
> + origin = "(default for unkown hardware)";
> + }
> + }
> + condlog(3, "%s: timeout for find_multipaths \"smart\" = %ds %s",
> + pp->dev, pp->find_multipaths_timeout, origin);
> + return 0;
> +}
> diff --git a/libmultipath/propsel.h b/libmultipath/propsel.h
> index 136f90605b91..b6475d0d9c71 100644
> --- a/libmultipath/propsel.h
> +++ b/libmultipath/propsel.h
> @@ -8,6 +8,7 @@ int select_hwhandler (struct config *conf, struct multipath * mp);
> int select_checker(struct config *conf, struct path *pp);
> int select_getuid (struct config *conf, struct path * pp);
> int select_prio (struct config *conf, struct path * pp);
> +int select_find_multipaths_timeout(struct config *conf, struct path * pp);
> int select_no_path_retry(struct config *conf, struct multipath *mp);
> int select_flush_on_last_del(struct config *conf, struct multipath *mp);
> int select_minio(struct config *conf, struct multipath *mp);
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index 32f4b2d0696c..d4e18df940ea 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -281,6 +281,7 @@ struct path {
> int io_err_disable_reinstate;
> int io_err_pathfail_cnt;
> int io_err_pathfail_starttime;
> + int find_multipaths_timeout;
> /* configlet pointers */
> struct hwentry * hwe;
> struct gen_path generic_path;
> diff --git a/multipath/main.c b/multipath/main.c
> index 9b53c13b3a78..b41621d267f7 100644
> --- a/multipath/main.c
> +++ b/multipath/main.c
> @@ -60,6 +60,7 @@
> #include "uxsock.h"
> #include "mpath_cmd.h"
> #include "foreign.h"
> +#include "propsel.h"
>
> int logsink;
> struct udev *udev;
> @@ -350,7 +351,8 @@ out:
> return r;
> }
>
> -static int print_cmd_valid(int k)
> +static int print_cmd_valid(int k, const vector pathvec,
> + struct config *conf)
> {
> int vals[] = { 1, 0, 2 };
>
> @@ -358,6 +360,13 @@ static int print_cmd_valid(int k)
> return 1;
>
> printf("DM_MULTIPATH_DEVICE_PATH=\"%d\"\n", vals[k]);
> + if (vals[k] == 2 && VECTOR_SIZE(pathvec) > 0) {
> + struct path *pp = VECTOR_SLOT(pathvec, 0);
> +
> + select_find_multipaths_timeout(conf, pp);
> + printf("FIND_MULTIPATHS_PATH_TMO=\"%d\"\n",
> + pp->find_multipaths_timeout);
> + }
> return k == 1;
> }
>
> @@ -523,7 +532,7 @@ configure (struct config *conf, enum mpath_cmds cmd,
>
> print_valid:
> if (cmd == CMD_VALID_PATH)
> - r = print_cmd_valid(r);
> + r = print_cmd_valid(r, pathvec, conf);
>
> out:
> if (refwwid)
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index 6965dacb5c68..94c419a078bf 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -983,6 +983,24 @@ The default is: \fBstrict\fR
> .
> .
> .TP
> +.B find_multipaths_timeout
> +Timeout, in seconds, to wait for additional paths after detecting the first
> +one, if \fIfind_multipaths
> +"smart"\fR (see above) is set. If the value is \fBpositive\fR, this timeout is used for all
> +unkown, non-blacklisted devices encountered. If the value is \fBnegative\fR
> +(recommended), it's only
> +applied to "known" devices that have an entry in multipath's hardware table,
> +either in the built-in table or in a \fIdevice\fR section; other ("unknown") devices will
> +use a timeout of only 1 second to avoid booting delays. The value 0 means
> +"use the built-in default". If \fIfind_multipath\fR has a value
> +other than \fIsmart\fR, this option has no effect.
> +.RS
> +.TP
> +The default is: \fB-10\fR (10s for known and 1s for unknown hardware)
> +.RE
> +.
> +.
> +.TP
> .B uxsock_timeout
> CLI receive timeout in milliseconds. For larger systems CLI commands
> might timeout before the multipathd lock is released and the CLI command
> --
> 2.16.1
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