[LU-15275] Skip router discovery on send path

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Assignee: Chris Horn
• Reporter: Chris Horn

Description

When the router checker is enabled, routes are regularly marked as out
of date w.r.t. discovery. This can cause upper level messages to be
delayed while the router undergoes discovery. We can avoid delaying
messages by relying on the router checker to initiate discovery of
routers. If we happen to send a message to a router before it has
been discovered then the worst case scenario is that the route is
actually down or we end up utilizing a subset of a multi-rail router's
interfaces. Both situations can be remedied by utilizing the
check_routers_before_use parameter.

Change the logic in lnet_handle_find_routed_path() so that we only
initiate discovery if the alive_router_check_interval is <= 0 (i.e.
router checker pings are disabled).

Comments

[Peter Jones]

Landed for 2.15

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/45684/
Subject: LU-15275 lnet: Skip router discovery on send path
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: c8e74c395d5634dbb0d9d8a86605bb36ab2b8233

[Gerrit Updater]

"Chris Horn <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45684
Subject: LU-15275 lnet: Skip router discovery on send path
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 178ea10ef4f2bb0781d0bdcc495aace48b30de6f

[Gerrit Updater]

"Chris Horn <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/45655
Subject: LU-15275 lnet: Prioritize routes that are already up to date
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 856513eddcc2e478b013952cf075c1d3d5cf7cf2