critical_section()在lvm2中的意義？

I asked:

Hi, I'm wondering the meaning behind critical_section(), can you talk a little about its basic purpose of it?

Kabi:

critical section is the section where lvm2 steps into mode where devices are 'suspended'.
which means -   you 'swap' device can be suspended - so any memory allocation may cause practical deadlock of your system.

 so in crtical section - there shell be 'minimum' allocation - so no new memory is needed.