Re: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbsimplementation

From: Timur Tabi
Date: Mon Apr 25 2005 - 18:14:18 EST

Bob Woodruff wrote:

There definitely needs to be a mechanism to prevent people from pinning
too much memory.

Any limit would have to be very high - definitely more than just half. What if the application needs to pin 2GB? The customer is not going to buy 4+ GB of RAM just because Linux doesn't like pinning more than half. In an x86-32 system, that would required PAE support and slow everything down.

Off the top of my head, I'd say Linux would need to allow all but 512MB to be pinned. So you have 3GB of RAM, Linux should allow you to pin 2.5GB.

Timur Tabi
Staff Software Engineer

One thing a Southern boy will never say is,
"I don't think duct tape will fix it."
-- Ed Smylie, NASA engineer for Apollo 13
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at