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authorSeongJae Park <sj@kernel.org>2021-11-05 23:46:42 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 23:30:44 +0300
commit90bebce9fcd6488ba6b010af3a16a0a0d7e44cb6 (patch)
treeae888606f9073a8c2708ae51ea7c562d8d5d350c
parent68536f8e01e571f553f78fa058ba543de3834452 (diff)
downloadlinux-90bebce9fcd6488ba6b010af3a16a0a0d7e44cb6.tar.xz
mm/damon/dbgfs: allow users to set initial monitoring target regions
Patch series "DAMON: Support Physical Memory Address Space Monitoring:. DAMON currently supports only virtual address spaces monitoring. It can be easily extended for various use cases and address spaces by configuring its monitoring primitives layer to use appropriate primitives implementations, though. This patchset implements monitoring primitives for the physical address space monitoring using the structure. The first 3 patches allow the user space users manually set the monitoring regions. The 1st patch implements the feature in the 'damon-dbgfs'. Then, patches for adding a unit tests (the 2nd patch) and updating the documentation (the 3rd patch) follow. Following 4 patches implement the physical address space monitoring primitives. The 4th patch makes some primitive functions for the virtual address spaces primitives reusable. The 5th patch implements the physical address space monitoring primitives. The 6th patch links the primitives to the 'damon-dbgfs'. Finally, 7th patch documents this new features. This patch (of 7): Some 'damon-dbgfs' users would want to monitor only a part of the entire virtual memory address space. The program interface users in the kernel space could use '->before_start()' callback or set the regions inside the context struct as they want, but 'damon-dbgfs' users cannot. For that reason, this introduces a new debugfs file called 'init_region'. 'damon-dbgfs' users can specify which initial monitoring target address regions they want by writing special input to the file. The input should describe each region in each line in the below form: <pid> <start address> <end address> Note that the regions will be updated to cover entire memory mapped regions after a 'regions update interval' is passed. If you want the regions to not be updated after the initial setting, you could set the interval as a very long time, say, a few decades. Link: https://lkml.kernel.org/r/20211012205711.29216-1-sj@kernel.org Link: https://lkml.kernel.org/r/20211012205711.29216-2-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Amit Shah <amit@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: David Hildenbrand <david@redhat.com> Cc: David Woodhouse <dwmw@amazon.com> Cc: Marco Elver <elver@google.com> Cc: Leonard Foerster <foersleo@amazon.de> Cc: Greg Thelen <gthelen@google.com> Cc: Markus Boehme <markubo@amazon.de> Cc: David Rienjes <rientjes@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/damon/dbgfs.c156
1 files changed, 154 insertions, 2 deletions
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 28d6abf27763..1cce53cd241d 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -394,6 +394,152 @@ out:
return ret;
}
+static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len)
+{
+ struct damon_target *t;
+ struct damon_region *r;
+ int written = 0;
+ int rc;
+
+ damon_for_each_target(t, c) {
+ damon_for_each_region(r, t) {
+ rc = scnprintf(&buf[written], len - written,
+ "%lu %lu %lu\n",
+ t->id, r->ar.start, r->ar.end);
+ if (!rc)
+ return -ENOMEM;
+ written += rc;
+ }
+ }
+ return written;
+}
+
+static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct damon_ctx *ctx = file->private_data;
+ char *kbuf;
+ ssize_t len;
+
+ kbuf = kmalloc(count, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+
+ mutex_lock(&ctx->kdamond_lock);
+ if (ctx->kdamond) {
+ mutex_unlock(&ctx->kdamond_lock);
+ len = -EBUSY;
+ goto out;
+ }
+
+ len = sprint_init_regions(ctx, kbuf, count);
+ mutex_unlock(&ctx->kdamond_lock);
+ if (len < 0)
+ goto out;
+ len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
+
+out:
+ kfree(kbuf);
+ return len;
+}
+
+static int add_init_region(struct damon_ctx *c,
+ unsigned long target_id, struct damon_addr_range *ar)
+{
+ struct damon_target *t;
+ struct damon_region *r, *prev;
+ unsigned long id;
+ int rc = -EINVAL;
+
+ if (ar->start >= ar->end)
+ return -EINVAL;
+
+ damon_for_each_target(t, c) {
+ id = t->id;
+ if (targetid_is_pid(c))
+ id = (unsigned long)pid_vnr((struct pid *)id);
+ if (id == target_id) {
+ r = damon_new_region(ar->start, ar->end);
+ if (!r)
+ return -ENOMEM;
+ damon_add_region(r, t);
+ if (damon_nr_regions(t) > 1) {
+ prev = damon_prev_region(r);
+ if (prev->ar.end > r->ar.start) {
+ damon_destroy_region(r, t);
+ return -EINVAL;
+ }
+ }
+ rc = 0;
+ }
+ }
+ return rc;
+}
+
+static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len)
+{
+ struct damon_target *t;
+ struct damon_region *r, *next;
+ int pos = 0, parsed, ret;
+ unsigned long target_id;
+ struct damon_addr_range ar;
+ int err;
+
+ damon_for_each_target(t, c) {
+ damon_for_each_region_safe(r, next, t)
+ damon_destroy_region(r, t);
+ }
+
+ while (pos < len) {
+ ret = sscanf(&str[pos], "%lu %lu %lu%n",
+ &target_id, &ar.start, &ar.end, &parsed);
+ if (ret != 3)
+ break;
+ err = add_init_region(c, target_id, &ar);
+ if (err)
+ goto fail;
+ pos += parsed;
+ }
+
+ return 0;
+
+fail:
+ damon_for_each_target(t, c) {
+ damon_for_each_region_safe(r, next, t)
+ damon_destroy_region(r, t);
+ }
+ return err;
+}
+
+static ssize_t dbgfs_init_regions_write(struct file *file,
+ const char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct damon_ctx *ctx = file->private_data;
+ char *kbuf;
+ ssize_t ret = count;
+ int err;
+
+ kbuf = user_input_str(buf, count, ppos);
+ if (IS_ERR(kbuf))
+ return PTR_ERR(kbuf);
+
+ mutex_lock(&ctx->kdamond_lock);
+ if (ctx->kdamond) {
+ ret = -EBUSY;
+ goto unlock_out;
+ }
+
+ err = set_init_regions(ctx, kbuf, ret);
+ if (err)
+ ret = err;
+
+unlock_out:
+ mutex_unlock(&ctx->kdamond_lock);
+ kfree(kbuf);
+ return ret;
+}
+
static ssize_t dbgfs_kdamond_pid_read(struct file *file,
char __user *buf, size_t count, loff_t *ppos)
{
@@ -445,6 +591,12 @@ static const struct file_operations target_ids_fops = {
.write = dbgfs_target_ids_write,
};
+static const struct file_operations init_regions_fops = {
+ .open = damon_dbgfs_open,
+ .read = dbgfs_init_regions_read,
+ .write = dbgfs_init_regions_write,
+};
+
static const struct file_operations kdamond_pid_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_kdamond_pid_read,
@@ -453,9 +605,9 @@ static const struct file_operations kdamond_pid_fops = {
static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx)
{
const char * const file_names[] = {"attrs", "schemes", "target_ids",
- "kdamond_pid"};
+ "init_regions", "kdamond_pid"};
const struct file_operations *fops[] = {&attrs_fops, &schemes_fops,
- &target_ids_fops, &kdamond_pid_fops};
+ &target_ids_fops, &init_regions_fops, &kdamond_pid_fops};
int i;
for (i = 0; i < ARRAY_SIZE(file_names); i++)