Messages in this thread | | | Date | Tue, 15 Apr 2014 15:43:15 +0200 | From | Emmanuel Colbus <> | Subject | [RFC][10/11][MANUX] Suggestion : kmalloc() |
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Finally, since cloning the Linux kernel gave me some ideas, I would like to give you a couple of suggestions of my own. Feel free to do what you want with them.
First, I'm not sure whether this has been done or not, but I would like to suggest you to mark your kernel memory allocator with gcc's malloc attribute (and mark kfree() as taking void*, not const void*).
Yes, I know, it apparently doesn't corresponds with what the malloc attribute's specification covers, since there are still pointers to the returned memory area somewhere else in the kernel. However, I would like to point out that this isn't relevant : in *any* malloc-like implementation, there will be such pointers somewhere in the allocator. What's important is whether they are such pointers *in the specific compilation units from which the allocator is called*.
And since the allocator can't call itself (well, I'm not sure for the Linux one, of course, but this happens to be true in mine), leaving kmalloc in a separate file allows setting this attribute, which gives a little speed boost to the code (that's what it did to my kernel when I did it). That's because it allows the compiler to know that two areas allocated with such a function *cannot* alias each other, which helps it optimize the memory accesses to them.
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