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74e404ce11
Use a new form of hints to reduce device scanning in vgchange -aay run by the udev rule for event based autoactivation. Standard hints allow a command with a named VG arg to scan only the PVs in the named VG, rather than scanning all available PVs. Standard hints are useful with a stable set of system devices. When new devices are arriving, as occurs during system startup, the hints are repeatedly invalidated, which makes standard hints unhelpful while devices are regularly appearing. This is the situation in which vgchange -aay is used, so standard hints are not generally helpful for autoactivation. In the context of system startup, pvscan --cache is keeping track of available PVs using the pvs_online files, similar to what the hints file does for a running system. Given this, a new hint mode, hints = "pvs_online", is added which derives an equivalent to standard hints, based on pvs_online files that are being created by udev-run pvscans. This hint mode is useful while devices are appearing, e.g. during system startup, and vgchange -aay can benefit from it. pvscan --cache -aay autoactivation already has a similar optimization (the "quick" activation case) that is based on the pvs_online file, but it is not implemented as a form of hints. This new form of hints is mainly useful in the context of event based autoactivation, during which standard hints are not useful. Once the system is in a steady state after startup (devices are not regularly appearing), the standard hints are most useful. The pvs_online hint method could be used on a running system, but would be no better than standard hints, and may be inferior because pvs_online files are not rigidly updated after system startup. |
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| .. | ||
| hints.c | ||
| hints.h | ||
| label.c | ||
| label.h | ||