[-mm PATCH] Memory controller improve user interface
balbir at linux.vnet.ibm.com
Wed Aug 29 15:44:15 PDT 2007
Dave Hansen wrote:
> On Thu, 2007-08-30 at 03:57 +0530, Balbir Singh wrote:
>> True, mmap() is a good example of such an interface for developers, I
>> am not sure about system admins though.
>> To quote Andrew
>> Reporting tools could run getpagesize() and do the arithmetic, but we
>> generally try to avoid exposing PAGE_SIZE, HZ, etc to userspace in this
> 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.
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