[tip:perf/core] tools lib fd array: Allow associating an integer cookie with each entry

From: tip-bot for Arnaldo Carvalho de Melo
Date: Fri Sep 26 2014 - 05:22:20 EST

Next message: tip-bot for Arnaldo Carvalho de Melo: "[tip:perf/core] perf evlist: Unmap when all refcounts to fd are gone and events drained"
Previous message: Stephen Rothwell: "linux-next: manual merge of the llvmlinux tree with the arm tree"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Commit-ID: 2171a9256862ec139a042832a9ae737b942ca882
Gitweb: http://git.kernel.org/tip/2171a9256862ec139a042832a9ae737b942ca882
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 8 Sep 2014 11:24:01 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 25 Sep 2014 16:46:55 -0300

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@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jean Pihet <jean.pihet@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Link: http://lkml.kernel.org/n/tip-0p00bn83quck3fio3kcs9vca@xxxxxxxxxxxxxx
---
tools/lib/api/fd/array.c | 28 ++++++++++++++++++++++++----
tools/lib/api/fd/array.h | 16 +++++++++++++++-
tools/perf/tests/fdarray.c | 8 ++++----
tools/perf/util/evlist.c | 2 +-
4 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
index 4889c7d..0e636c4 100644
--- a/tools/lib/api/fd/array.c
+++ b/tools/lib/api/fd/array.c
@@ -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)
+ if (fda->entries[fd].revents & revents) {
+ if (entry_destructor)
+ entry_destructor(fda, fd);
+
continue;
+ }

- if (fd != nr)
+ if (fd != nr) {
fda->entries[nr] = fda->entries[fd];
+ fda->priv[nr] = fda->priv[fd];
+ }

++nr;
}
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
index de38361..45db018 100644
--- a/tools/lib/api/fd/array.h
+++ b/tools/lib/api/fd/array.h
@@ -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);

diff --git a/tools/perf/tests/fdarray.c b/tools/perf/tests/fdarray.c
index a0fea62..d24b837 100644
--- a/tools/perf/tests/fdarray.c
+++ b/tools/perf/tests/fdarray.c
@@ -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",
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index efddee5..61d18dc 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -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)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: tip-bot for Arnaldo Carvalho de Melo: "[tip:perf/core] perf evlist: Unmap when all refcounts to fd are gone and events drained"
Previous message: Stephen Rothwell: "linux-next: manual merge of the llvmlinux tree with the arm tree"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]