> Right, you'd have to be careful since you (briefly) increase your > memory requirement. I only recommend that when the cause of the > swapping is gone already and Linux has released most slots on the swap > disk again. CP would continue to care for the pages even though Linux > does not need the contents. In that case there's little stirring and > the benefit is that CP can then release the backing of the VDISK. > > PS Instead of the discussed wibni's, I'd rather have DIAG10 for VDISK > on the wish list (call it CMM-3 if that looks better on your PBC). The > things in Linux to exploit that are mostly there (aka TRIM support for > SSD devices). > > | Rob
It would be perhaps a bit "underhanded" to use it this way (in terms of it being an undocumented side effect), but we already do have a Diag 10 type "Trim" function for vdisks - a "format write" is essentially converted into a page release call when simulated. I'd have to check with our I/O guys exactly which CCW that is, and whether there are any restrictions on when it results in the page release (probably needs to be at least 4K in size, since vdisks are 512 byte FBA devices, but Linux usage is 4K anyway, correct?). And if folks really think an official, documented Trim function for vdisks is required, by all means, open a requirement. It likely won't get implemented otherwise. - Bill Bill Holder, Senior Software Engineer IBM z/VM Development, Memory Management, Endicott, NY Phone: 607-429-3640 IBM TieLine: 620-3640 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
