tools lib fd array: Allow associating an integer cookie with each entry

We will use this in perf's evlist class so that it can, at
fdarray__filter() time, to unmap the associated ring buffer.

We may need to have further info associated with each fdarray entry, in
that case we'll make that int array a 'union fdarray_priv' one and put a
pointer there so that users can stash whatever they want there. For now,
an int is enough tho.

v2: Add clarification to the per array entry priv area, as well as make
    it a union, which makes usage a bit longer, but if/when we make it
    use more space by allowing per entry pointers existing users source
    code will not have to be changed, just rebuilt.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Link: http://lkml.kernel.org/n/tip-0p00bn83quck3fio3kcs9vca@git.kernel.org
This commit is contained in:
Arnaldo Carvalho de Melo 2014-09-08 11:24:01 -03:00
parent 8239698603
commit 2171a92568
4 changed files with 45 additions and 11 deletions

View file

@ -13,21 +13,31 @@
void fdarray__init(struct fdarray *fda, int nr_autogrow)
{
fda->entries = NULL;
fda->priv = NULL;
fda->nr = fda->nr_alloc = 0;
fda->nr_autogrow = nr_autogrow;
}
int fdarray__grow(struct fdarray *fda, int nr)
{
void *priv;
int nr_alloc = fda->nr_alloc + nr;
size_t psize = sizeof(fda->priv[0]) * nr_alloc;
size_t size = sizeof(struct pollfd) * nr_alloc;
struct pollfd *entries = realloc(fda->entries, size);
if (entries == NULL)
return -ENOMEM;
priv = realloc(fda->priv, psize);
if (priv == NULL) {
free(entries);
return -ENOMEM;
}
fda->nr_alloc = nr_alloc;
fda->entries = entries;
fda->priv = priv;
return 0;
}
@ -50,6 +60,7 @@ struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow)
void fdarray__exit(struct fdarray *fda)
{
free(fda->entries);
free(fda->priv);
fdarray__init(fda, 0);
}
@ -61,6 +72,8 @@ void fdarray__delete(struct fdarray *fda)
int fdarray__add(struct fdarray *fda, int fd, short revents)
{
int pos = fda->nr;
if (fda->nr == fda->nr_alloc &&
fdarray__grow(fda, fda->nr_autogrow) < 0)
return -ENOMEM;
@ -68,10 +81,11 @@ int fdarray__add(struct fdarray *fda, int fd, short revents)
fda->entries[fda->nr].fd = fd;
fda->entries[fda->nr].events = revents;
fda->nr++;
return 0;
return pos;
}
int fdarray__filter(struct fdarray *fda, short revents)
int fdarray__filter(struct fdarray *fda, short revents,
void (*entry_destructor)(struct fdarray *fda, int fd))
{
int fd, nr = 0;
@ -79,11 +93,17 @@ int fdarray__filter(struct fdarray *fda, short revents)
return 0;
for (fd = 0; fd < fda->nr; ++fd) {
if (fda->entries[fd].revents & revents)
continue;
if (fda->entries[fd].revents & revents) {
if (entry_destructor)
entry_destructor(fda, fd);
if (fd != nr)
continue;
}
if (fd != nr) {
fda->entries[nr] = fda->entries[fd];
fda->priv[nr] = fda->priv[fd];
}
++nr;
}

View file

@ -5,11 +5,24 @@
struct pollfd;
/**
* struct fdarray: Array of file descriptors
*
* @priv: Per array entry priv area, users should access just its contents,
* not set it to anything, as it is kept in synch with @entries, being
* realloc'ed, * for instance, in fdarray__{grow,filter}.
*
* I.e. using 'fda->priv[N].idx = * value' where N < fda->nr is ok,
* but doing 'fda->priv = malloc(M)' is not allowed.
*/
struct fdarray {
int nr;
int nr_alloc;
int nr_autogrow;
struct pollfd *entries;
union {
int idx;
} *priv;
};
void fdarray__init(struct fdarray *fda, int nr_autogrow);
@ -20,7 +33,8 @@ void fdarray__delete(struct fdarray *fda);
int fdarray__add(struct fdarray *fda, int fd, short revents);
int fdarray__poll(struct fdarray *fda, int timeout);
int fdarray__filter(struct fdarray *fda, short revents);
int fdarray__filter(struct fdarray *fda, short revents,
void (*entry_destructor)(struct fdarray *fda, int fd));
int fdarray__grow(struct fdarray *fda, int extra);
int fdarray__fprintf(struct fdarray *fda, FILE *fp);

View file

@ -36,7 +36,7 @@ int test__fdarray__filter(void)
}
fdarray__init_revents(fda, POLLIN);
nr_fds = fdarray__filter(fda, POLLHUP);
nr_fds = fdarray__filter(fda, POLLHUP, NULL);
if (nr_fds != fda->nr_alloc) {
pr_debug("\nfdarray__filter()=%d != %d shouldn't have filtered anything",
nr_fds, fda->nr_alloc);
@ -44,7 +44,7 @@ int test__fdarray__filter(void)
}
fdarray__init_revents(fda, POLLHUP);
nr_fds = fdarray__filter(fda, POLLHUP);
nr_fds = fdarray__filter(fda, POLLHUP, NULL);
if (nr_fds != 0) {
pr_debug("\nfdarray__filter()=%d != %d, should have filtered all fds",
nr_fds, fda->nr_alloc);
@ -57,7 +57,7 @@ int test__fdarray__filter(void)
pr_debug("\nfiltering all but fda->entries[2]:");
fdarray__fprintf_prefix(fda, "before", stderr);
nr_fds = fdarray__filter(fda, POLLHUP);
nr_fds = fdarray__filter(fda, POLLHUP, NULL);
fdarray__fprintf_prefix(fda, " after", stderr);
if (nr_fds != 1) {
pr_debug("\nfdarray__filter()=%d != 1, should have left just one event", nr_fds);
@ -78,7 +78,7 @@ int test__fdarray__filter(void)
pr_debug("\nfiltering all but (fda->entries[0], fda->entries[3]):");
fdarray__fprintf_prefix(fda, "before", stderr);
nr_fds = fdarray__filter(fda, POLLHUP);
nr_fds = fdarray__filter(fda, POLLHUP, NULL);
fdarray__fprintf_prefix(fda, " after", stderr);
if (nr_fds != 2) {
pr_debug("\nfdarray__filter()=%d != 2, should have left just two events",

View file

@ -435,7 +435,7 @@ int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
{
return fdarray__filter(&evlist->pollfd, revents_and_mask);
return fdarray__filter(&evlist->pollfd, revents_and_mask, NULL);
}
int perf_evlist__poll(struct perf_evlist *evlist, int timeout)