Messages in this thread | | | Date | Mon, 25 Feb 2008 23:46:16 -0600 | From | Paul Jackson <> | Subject | Re: [patch 3/6] mempolicy: add MPOL_F_STATIC_NODES flag |
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David wrote: +static inline int mpol_store_user_nodemask(const struct mempolicy *pol) +{ + return !!(pol->flags & MPOL_F_STATIC_NODES); +}
Why the double-negative? As best as I can tell, the return value of mpol_store_user_nodemask() is only used in conditional contexts:
$ grep mpol_store_user_nodemask mm/mempolicy.c static inline int mpol_store_user_nodemask(const struct mempolicy *pol) if (mpol_store_user_nodemask(policy)) if (!mpol_store_user_nodemask(a)) if (!mpol_store_user_nodemask(pol) &&
So I see no need to waste the instructions needed (in the three copies of this code, since it's static inline) to convert a non-zero value to exactly the value 1.
Hmmm ... speaking of static inline ... I can knock 600 bytes (that's IA64 bytes, so equivalent to about 300 x86 bytes) off the kernel text size by not inlining the mm/mempolicy.c routines check_pgd_range() and interleave_nid(). I wonder if that would be worth doing. Perhaps those two routines are in sufficiently tight corners that the duplicate copies of them is needed.
-- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.940.382.4214
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