[PATCH] vmevent: Use 'struct vmevent_attr' for vmevent_fd() ABI
From: Pekka Enberg
Date: Tue Mar 06 2012 - 15:52:24 EST
This patch introduces 'struct vmevent_attr' and converts the vmevent_fd() ABI
to use it which makes the ABI much more flexible.
Originally-by: Leonid Moiseichuk <leonid.moiseichuk@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
include/linux/vmevent.h | 66 +++++++++----
mm/vmevent.c | 186 +++++++++++++++++++++++-----------
tools/testing/vmevent/vmevent-test.c | 54 +++++++---
3 files changed, 212 insertions(+), 94 deletions(-)
diff --git a/include/linux/vmevent.h b/include/linux/vmevent.h
index 4f577ee..64357e4 100644
--- a/include/linux/vmevent.h
+++ b/include/linux/vmevent.h
@@ -3,53 +3,83 @@
#include <linux/types.h>
+/*
+ * Types of memory attributes which could be monitored through vmevent API
+ */
enum {
- VMEVENT_TYPE_FREE_THRESHOLD = 1ULL << 0,
- VMEVENT_TYPE_SAMPLE = 1ULL << 1,
+ VMEVENT_ATTR_NR_AVAIL_PAGES = 1UL,
+ VMEVENT_ATTR_NR_FREE_PAGES = 2UL,
+ VMEVENT_ATTR_NR_SWAP_PAGES = 3UL,
+
+ VMEVENT_ATTR_MAX /* non-ABI */
};
+/*
+ * Attribute state bits for threshold
+ */
enum {
- VMEVENT_EATTR_NR_AVAIL_PAGES = 1ULL << 0,
- VMEVENT_EATTR_NR_FREE_PAGES = 1ULL << 1,
- VMEVENT_EATTR_NR_SWAP_PAGES = 1ULL << 2,
+ /*
+ * Sample value is less than user-specified value
+ */
+ VMEVENT_ATTR_STATE_VALUE_LT = (1UL << 0),
};
-struct vmevent_config {
+struct vmevent_attr {
/*
- * Size of the struct for ABI extensibility.
+ * Value in pages delivered with pointed attribute
*/
- __u32 size;
+ __u64 value;
/*
- * Notification type bitmask
+ * Type of profiled attribute from VMEVENT_ATTR_XXX
*/
- __u64 type;
+ __u32 type;
+
+ /*
+ * Bitmask of current attribute value (see VMEVENT_ATTR_STATE_XXX)
+ */
+ __u32 state;
+};
+#define VMEVENT_CONFIG_MAX_ATTRS 32
+
+/*
+ * Configuration structure to get notifications and attributes values
+ */
+struct vmevent_config {
/*
- * Attributes that are delivered as part of events.
+ * Size of the struct for ABI extensibility.
*/
- __u64 event_attrs;
+ __u32 size;
/*
- * Threshold of free pages in the system.
+ * Counter of number monitored attributes
*/
- __u32 free_pages_threshold;
+ __u32 counter;
/*
* Sample period in nanoseconds
*/
__u64 sample_period_ns;
+
+ /*
+ * Attributes that are monitored and delivered as part of events
+ */
+ struct vmevent_attr attrs[VMEVENT_CONFIG_MAX_ATTRS];
};
struct vmevent_event {
/*
- * Size of the struct for ABI extensibility.
+ * Counter of attributes in this VM event
*/
- __u32 size;
+ __u32 counter;
- __u64 attrs;
+ __u32 padding;
- __u64 attr_values[];
+ /*
+ * Attributes for this VM event
+ */
+ struct vmevent_attr attrs[];
};
#endif /* _LINUX_VMEVENT_H */
diff --git a/mm/vmevent.c b/mm/vmevent.c
index 37d2c5f..ab6a043 100644
--- a/mm/vmevent.c
+++ b/mm/vmevent.c
@@ -24,10 +24,10 @@ struct vmevent_watch {
bool pending;
/*
- * Attributes
- */
+ * Attributes that are exported as part of delivered VM events.
+ */
unsigned long nr_attrs;
- u64 attr_values[64];
+ struct vmevent_attr *sample_attrs;
/* sampling */
struct hrtimer timer;
@@ -36,54 +36,87 @@ struct vmevent_watch {
wait_queue_head_t waitq;
};
-static bool vmevent_match(struct vmevent_watch *watch,
- struct vmevent_watch_event *event)
+typedef u64 (*vmevent_attr_sample_fn)(struct vmevent_watch *watch);
+
+static u64 vmevent_attr_swap_pages(struct vmevent_watch *watch)
{
- if (watch->config.type & VMEVENT_TYPE_FREE_THRESHOLD) {
- if (event->nr_free_pages > watch->config.free_pages_threshold)
- return false;
- }
+#ifdef CONFIG_SWAP
+ struct sysinfo si;
+
+ si_swapinfo(&si);
- return true;
+ return si.totalswap;
+#else
+ return 0;
+#endif
}
-static void vmevent_sample(struct vmevent_watch *watch)
+static u64 vmevent_attr_free_pages(struct vmevent_watch *watch)
+{
+ return global_page_state(NR_FREE_PAGES);
+}
+
+static u64 vmevent_attr_avail_pages(struct vmevent_watch *watch)
{
- struct vmevent_watch_event event;
struct sysinfo si;
- int n = 0;
- memset(&event, 0, sizeof(event));
+ si_meminfo(&si);
- event.nr_free_pages = global_page_state(NR_FREE_PAGES);
+ return si.totalram;
+}
- si_meminfo(&si);
- event.nr_avail_pages = si.totalram;
+static vmevent_attr_sample_fn attr_samplers[] = {
+ [VMEVENT_ATTR_NR_AVAIL_PAGES] = vmevent_attr_avail_pages,
+ [VMEVENT_ATTR_NR_FREE_PAGES] = vmevent_attr_free_pages,
+ [VMEVENT_ATTR_NR_SWAP_PAGES] = vmevent_attr_swap_pages,
+};
-#ifdef CONFIG_SWAP
- if (watch->config.event_attrs & VMEVENT_EATTR_NR_SWAP_PAGES) {
- si_swapinfo(&si);
- event.nr_swap_pages = si.totalswap;
+static u64 vmevent_sample_attr(struct vmevent_watch *watch, struct vmevent_attr *attr)
+{
+ vmevent_attr_sample_fn fn = attr_samplers[attr->type];
+
+ return fn(watch);
+}
+
+static bool vmevent_match(struct vmevent_watch *watch)
+{
+ struct vmevent_config *config = &watch->config;
+ int i;
+
+ for (i = 0; i < config->counter; i++) {
+ struct vmevent_attr *attr = &config->attrs[i];
+ u64 value;
+
+ if (!attr->state)
+ continue;
+
+ value = vmevent_sample_attr(watch, attr);
+
+ if (attr->state & VMEVENT_ATTR_STATE_VALUE_LT) {
+ if (value < attr->value)
+ return true;
+ }
}
-#endif
- if (!vmevent_match(watch, &event))
+ return false;
+}
+
+static void vmevent_sample(struct vmevent_watch *watch)
+{
+ int i;
+
+ if (!vmevent_match(watch))
return;
mutex_lock(&watch->mutex);
watch->pending = true;
- if (watch->config.event_attrs & VMEVENT_EATTR_NR_AVAIL_PAGES)
- watch->attr_values[n++] = event.nr_avail_pages;
-
- if (watch->config.event_attrs & VMEVENT_EATTR_NR_FREE_PAGES)
- watch->attr_values[n++] = event.nr_free_pages;
-
- if (watch->config.event_attrs & VMEVENT_EATTR_NR_SWAP_PAGES)
- watch->attr_values[n++] = event.nr_swap_pages;
+ for (i = 0; i < watch->nr_attrs; i++) {
+ struct vmevent_attr *attr = &watch->sample_attrs[i];
- watch->nr_attrs = n;
+ attr->value = vmevent_sample_attr(watch, attr);
+ }
mutex_unlock(&watch->mutex);
}
@@ -132,43 +165,45 @@ static unsigned int vmevent_poll(struct file *file, poll_table *wait)
static ssize_t vmevent_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct vmevent_watch *watch = file->private_data;
- struct vmevent_event event;
+ struct vmevent_event *event;
ssize_t ret = 0;
- u64 attr_size;
-
- mutex_lock(&watch->mutex);
+ u32 size;
+ int i;
- if (!watch->pending)
- goto out_unlock;
+ size = sizeof(*event) + watch->nr_attrs * sizeof(struct vmevent_attr);
- attr_size = watch->nr_attrs * sizeof(u64);
+ if (count < size)
+ return -EINVAL;
- memset(&event, 0, sizeof(event));
- event.size = sizeof(struct vmevent_event) + attr_size;
- event.attrs = watch->config.event_attrs;
+ mutex_lock(&watch->mutex);
- if (count < sizeof(event))
+ if (!watch->pending)
goto out_unlock;
- if (copy_to_user(buf, &event, sizeof(event))) {
- ret = -EFAULT;
+ event = kmalloc(size, GFP_KERNEL);
+ if (!event) {
+ ret = -ENOMEM;
goto out_unlock;
}
- count -= sizeof(event);
+ for (i = 0; i < watch->nr_attrs; i++) {
+ memcpy(&event->attrs[i], &watch->sample_attrs[i], sizeof(struct vmevent_attr));
+ }
- if (count > attr_size)
- count = attr_size;
+ event->counter = watch->nr_attrs;
- if (copy_to_user(buf + sizeof(event), watch->attr_values, count)) {
+ if (copy_to_user(buf, event, size)) {
ret = -EFAULT;
- goto out_unlock;
+ goto out_free;
}
ret = count;
watch->pending = false;
+out_free:
+ kfree(event);
+
out_unlock:
mutex_unlock(&watch->mutex);
@@ -207,6 +242,42 @@ static struct vmevent_watch *vmevent_watch_alloc(void)
return watch;
}
+static int vmevent_setup_watch(struct vmevent_watch *watch)
+{
+ struct vmevent_config *config = &watch->config;
+ struct vmevent_attr *attrs = NULL;
+ unsigned long nr;
+ int i;
+
+ nr = 0;
+
+ for (i = 0; i < config->counter; i++) {
+ struct vmevent_attr *attr = &config->attrs[i];
+ size_t size;
+ void *new;
+
+ if (attr->type >= VMEVENT_ATTR_MAX)
+ continue;
+
+ size = sizeof(struct vmevent_attr) * (nr + 1);
+
+ new = krealloc(attrs, size, GFP_KERNEL);
+ if (!new) {
+ kfree(attrs);
+ return -ENOMEM;
+ }
+
+ attrs = new;
+
+ attrs[nr++].type = attr->type;
+ }
+
+ watch->sample_attrs = attrs;
+ watch->nr_attrs = nr;
+
+ return 0;
+}
+
static int vmevent_copy_config(struct vmevent_config __user *uconfig,
struct vmevent_config *config)
{
@@ -216,14 +287,6 @@ static int vmevent_copy_config(struct vmevent_config __user *uconfig,
if (ret)
return -EFAULT;
- if (!config->type)
- return -EINVAL;
-
- if (config->type & VMEVENT_TYPE_SAMPLE) {
- if (config->sample_period_ns < NSEC_PER_MSEC)
- return -EINVAL;
- }
-
return 0;
}
@@ -243,6 +306,10 @@ SYSCALL_DEFINE1(vmevent_fd,
if (err)
goto err_free;
+ err = vmevent_setup_watch(watch);
+ if (err)
+ goto err_free;
+
fd = get_unused_fd_flags(O_RDONLY);
if (fd < 0) {
err = fd;
@@ -257,8 +324,7 @@ SYSCALL_DEFINE1(vmevent_fd,
fd_install(fd, file);
- if (watch->config.type & VMEVENT_TYPE_SAMPLE)
- vmevent_start_timer(watch);
+ vmevent_start_timer(watch);
return fd;
diff --git a/tools/testing/vmevent/vmevent-test.c b/tools/testing/vmevent/vmevent-test.c
index f268034..534f827 100644
--- a/tools/testing/vmevent/vmevent-test.c
+++ b/tools/testing/vmevent/vmevent-test.c
@@ -32,12 +32,24 @@ int main(int argc, char *argv[])
printf("Physical pages: %ld\n", phys_pages);
config = (struct vmevent_config) {
- .type = VMEVENT_TYPE_SAMPLE | VMEVENT_TYPE_FREE_THRESHOLD,
- .event_attrs = VMEVENT_EATTR_NR_AVAIL_PAGES
- | VMEVENT_EATTR_NR_FREE_PAGES
- | VMEVENT_EATTR_NR_SWAP_PAGES,
.sample_period_ns = 1000000000L,
- .free_pages_threshold = phys_pages,
+ .counter = 4,
+ .attrs = {
+ [0] = {
+ .type = VMEVENT_ATTR_NR_FREE_PAGES,
+ .state = VMEVENT_ATTR_STATE_VALUE_LT,
+ .value = phys_pages,
+ },
+ [1] = {
+ .type = VMEVENT_ATTR_NR_AVAIL_PAGES,
+ },
+ [2] = {
+ .type = VMEVENT_ATTR_NR_SWAP_PAGES,
+ },
+ [3] = {
+ .type = 0xffff, /* invalid */
+ },
+ },
};
fd = sys_vmevent_fd(&config);
@@ -47,9 +59,10 @@ int main(int argc, char *argv[])
}
for (i = 0; i < 10; i++) {
- char buffer[sizeof(struct vmevent_event) + 3 * sizeof(uint64_t)];
+ char buffer[sizeof(struct vmevent_event) + 4 * sizeof(struct vmevent_attr)];
struct vmevent_event *event;
int n = 0;
+ int idx;
pollfd.fd = fd;
pollfd.events = POLLIN;
@@ -68,16 +81,25 @@ int main(int argc, char *argv[])
event = (void *) buffer;
- printf("VM event (%Lu bytes):\n", event->size);
-
- if (event->attrs & VMEVENT_EATTR_NR_AVAIL_PAGES)
- printf(" VMEVENT_EATTR_NR_AVAIL_PAGES: %Lu\n", event->attr_values[n++]);
-
- if (event->attrs & VMEVENT_EATTR_NR_FREE_PAGES)
- printf(" VMEVENT_EATTR_NR_FREE_PAGES : %Lu\n", event->attr_values[n++]);
-
- if (event->attrs & VMEVENT_EATTR_NR_SWAP_PAGES)
- printf(" VMEVENT_EATTR_NR_SWAP_PAGES : %Lu\n", event->attr_values[n++]);
+ printf("VM event (%u attributes):\n", event->counter);
+
+ for (idx = 0; idx < event->counter; idx++) {
+ struct vmevent_attr *attr = &event->attrs[idx];
+
+ switch (attr->type) {
+ case VMEVENT_ATTR_NR_AVAIL_PAGES:
+ printf(" VMEVENT_ATTR_NR_AVAIL_PAGES: %Lu\n", attr->value);
+ break;
+ case VMEVENT_ATTR_NR_FREE_PAGES:
+ printf(" VMEVENT_ATTR_NR_FREE_PAGES: %Lu\n", attr->value);
+ break;
+ case VMEVENT_ATTR_NR_SWAP_PAGES:
+ printf(" VMEVENT_ATTR_NR_SWAP_PAGES: %Lu\n", attr->value);
+ break;
+ default:
+ printf(" Unknown attribute: %Lu\n", attr->value);
+ }
+ }
}
if (close(fd) < 0) {
perror("close failed");
--
1.7.6.5
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