sysfs interface to transparent hugepages

[Ben Hutchings <ben@decadent.org.uk>]

[-- Attachment #1: Type: text/plain, Size: 1374 bytes --]

This kind of cute format:

       if (test_bit(enabled, &transparent_hugepage_flags)) {
               VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags));
               return sprintf(buf, "[always] madvise never\n");
       } else if (test_bit(req_madv, &transparent_hugepage_flags))
               return sprintf(buf, "always [madvise] never\n");
       else
               return sprintf(buf, "always madvise [never]\n");

is probably nice for a kernel developer or experimental user poking
around in sysfs.  But sysfs is mostly meant for programs to read and
write, and this format is unnecessarily complex for a program to parse.

Please use separate attributes for the current value and available
values, like cpufreq does.  I know there are other examples of the above
format, but not everything already in sysfs is a *good* example!

This, on the other hand, is totally ridiculous:

       if (test_bit(flag, &transparent_hugepage_flags))
               return sprintf(buf, "[yes] no\n");
       else
               return sprintf(buf, "yes [no]\n");

Why show the possible values of a boolean?  I can't even find any
examples of 'yes' and 'no' rather than '1' and '0'.

And really, why add boolean flags for a tristate at all?

Ben.

-- 
Ben Hutchings
Once a job is fouled up, anything done to improve it makes it worse.

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 828 bytes --]