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    SubjectRe: [PATCH 03/10] jump label v11: base patch
    On Tue, Sep 21, 2010 at 03:12:32PM +0200, Andi Kleen wrote:
    > On Fri, Sep 17, 2010 at 11:09:00AM -0400, Jason Baron wrote:
    > > +extern void arch_jump_label_transform(struct jump_entry *entry,
    > > + enum jump_label_type type);
    > > +extern void jump_label_update(unsigned long key, enum jump_label_type type);
    > > +extern void jump_label_apply_nops(struct module *mod);
    > > +extern void arch_jump_label_text_poke_early(jump_label_t addr);
    > These function names are too long.
    > Also it would be better if the types for the pointers are kept
    > instead of casting to unsigned long. All the variables
    > are ints right?

    So far, yes. But I didn't want to force this, in case the users of the
    API wanted to use other types. But I'm ok with 'int *' here.

    > > +#define JUMP_LABEL_HASH_BITS 6
    > > +static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE];
    > It's not clear to me why this hash table is needed. There should
    > not be that many trace points, is it that big a problem to simply
    > walk all the sections when something is changed?
    > Or maybe the sections could be just sorted and a binary search used
    > like with exception tables.
    > I suspect that would simplify a lot of code.
    > Overall I like the idea, but the current code is too complicated
    > for the benefit I think.
    > Can it be put on a diet?
    > -Andi

    So there are ~150 tracepoints, but this code is also being proposed for
    use with 'dynamic debug' of which there are > 1000, and I'm hoping for
    more users moving forward.

    Also, I think the hash table deals nicely with modules. I create a
    linked list of only those module sections that are relevant to each hash
    bucket. If you search through all the section on each enable/disable,
    its going to be proportional to the number of modules as well.



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