Thread (15 messages) 15 messages, 4 authors, 2007-08-30

Re: [-mm PATCH] Memory controller improve user interface

From: Balbir Singh <hidden>
Date: 2007-08-29 22:45:32
Also in: lkml

Dave Hansen wrote:
On Thu, 2007-08-30 at 03:57 +0530, Balbir Singh wrote:
quoted
True, mmap() is a good example of such an interface for developers, I
am not sure about system admins though.

To quote Andrew
<quote>
Reporting tools could run getpagesize() and do the arithmetic, but we
generally try to avoid exposing PAGE_SIZE, HZ, etc to userspace in this
manner.
</quote>
Well, rounding to PAGE_SIZE exposes PAGE_SIZE as well, just in a
non-intuitive fashion. :)
Agreed, but the user might choose to ignore it altogether.
If we're going to modify what the user specifies, we should probably at
least mandate that writes are only a "suggestion" and users must read
back the value to ensure what actually got committed.
Agreed, excellent suggestion!
If we're going to round in any direction, shouldn't we round up?  If a
user specifies 4097 bytes and uses two pages, we don't want to complain
when they hit that second page.  
Absolutely, I used rounding to mean round up, truncation for rounding down.

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL

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