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SubjectRe: [PATCH 4/9] perf kmem: Implement stat --page --caller
Hi Arnaldo,

On Mon, Apr 13, 2015 at 10:40:24AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Apr 06, 2015 at 02:36:11PM +0900, Namhyung Kim escreveu:
> > +static int build_alloc_func_list(void)
> > +{
> > + int ret;
> > + struct map *kernel_map;
> > + struct symbol *sym;
> > + struct rb_node *node;
> > + struct alloc_func *func;
> > + struct machine *machine = &kmem_session->machines.host;
> > +
>
> Why having a blank like here?

Will remove.

>
> > + regex_t alloc_func_regex;
> > + const char pattern[] = "^_?_?(alloc|get_free|get_zeroed)_pages?";
> > +
> > + ret = regcomp(&alloc_func_regex, pattern, REG_EXTENDED);
> > + if (ret) {
> > + char err[BUFSIZ];
> > +
> > + regerror(ret, &alloc_func_regex, err, sizeof(err));
> > + pr_err("Invalid regex: %s\n%s", pattern, err);
> > + return -EINVAL;
> > + }
> > +
> > + kernel_map = machine->vmlinux_maps[MAP__FUNCTION];
> > + map__load(kernel_map, NULL);
>
> What if the map can't be loaded?

Hmm.. yes, I need to check the return code.


>
> > +
> > + map__for_each_symbol(kernel_map, sym, node) {
> > + if (regexec(&alloc_func_regex, sym->name, 0, NULL, 0))
> > + continue;
> > +
> > + func = realloc(alloc_func_list,
> > + (nr_alloc_funcs + 1) * sizeof(*func));
> > + if (func == NULL)
> > + return -ENOMEM;
> > +
> > + pr_debug("alloc func: %s\n", sym->name);
> > + func[nr_alloc_funcs].start = sym->start;
> > + func[nr_alloc_funcs].end = sym->end;
> > + func[nr_alloc_funcs].name = sym->name;
> > +
> > + alloc_func_list = func;
> > + nr_alloc_funcs++;
> > + }
> > +
> > + qsort(alloc_func_list, nr_alloc_funcs, sizeof(*func), funcmp);
> > +
> > + regfree(&alloc_func_regex);
> > + return 0;
> > +}
> > +
> > +/*
> > + * Find first non-memory allocation function from callchain.
> > + * The allocation functions are in the 'alloc_func_list'.
> > + */
> > +static u64 find_callsite(struct perf_evsel *evsel, struct perf_sample *sample)
> > +{
> > + struct addr_location al;
> > + struct machine *machine = &kmem_session->machines.host;
> > + struct callchain_cursor_node *node;
> > +
> > + if (alloc_func_list == NULL)
> > + build_alloc_func_list();

And here too..


> > +
> > + al.thread = machine__findnew_thread(machine, sample->pid, sample->tid);
> > + sample__resolve_callchain(sample, NULL, evsel, &al, 16);
> > +
> > + callchain_cursor_commit(&callchain_cursor);
> > + while (true) {
> > + struct alloc_func key, *caller;
> > + u64 addr;
> > +
> > + node = callchain_cursor_current(&callchain_cursor);
> > + if (node == NULL)
> > + break;
> > +
> > + key.start = key.end = node->ip;
> > + caller = bsearch(&key, alloc_func_list, nr_alloc_funcs,
> > + sizeof(key), callcmp);
> > + if (!caller) {
> > + /* found */
> > + if (node->map)
> > + addr = map__unmap_ip(node->map, node->ip);
> > + else
> > + addr = node->ip;
> > +
> > + return addr;
> > + } else
> > + pr_debug3("skipping alloc function: %s\n", caller->name);
> > +
> > + callchain_cursor_advance(&callchain_cursor);
> > + }
> > +
> > + pr_debug2("unknown callsite: %"PRIx64 "\n", sample->ip);
> > + return sample->ip;
> > +}
> > +
> > +static struct page_stat *search_page(u64 page, bool create)
> > {
> > struct rb_node **node = &page_tree.rb_node;
> > struct rb_node *parent = NULL;
> > @@ -357,6 +491,41 @@ static struct page_stat *search_page_alloc_stat(struct page_stat *stat, bool cre
> > return data;
> > }
> >
> > +static struct page_stat *search_page_caller_stat(u64 callsite, bool create)
> > +{
> > + struct rb_node **node = &page_caller_tree.rb_node;
> > + struct rb_node *parent = NULL;
> > + struct page_stat *data;
>
> Please use the "findnew" idiom to name this function, looking at only
> its name one things it searches a tree, a read only operation, but it
> may insert elements too, a modify operation.
>
> Since we use the findnew idiom elsewhere for operations that do that,
> i.e. optimize the "new" part of "findnew" by using the "find" part,
> please use it here as well.

OK. Will change and resend v7 soon.

Thanks for your review!
Namhyung


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