The patch titled
Subject: mm/damon/dbgfs: export kdamond pid to the user space
has been added to the -mm tree. Its filename is
mm-damon-dbgfs-export-kdamond-pid-to-the-user-space.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-damon-dbgfs-export-kdamond-pid-to-the-user-space.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-damon-dbgfs-export-kdamond-pid-to-the-user-space.patch
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------------------------------------------------------
From: SeongJae Park <sjpark@xxxxxxxxx>
Subject: mm/damon/dbgfs: export kdamond pid to the user space
For CPU usage accounting, knowing pid of the monitoring thread could be
helpful. For example, users could use cpuaccount cgroups with the pid.
This commit therefore exports the pid of currently running monitoring
thread to the user space via 'kdamond_pid' file in the debugfs directory.
Link: https://lkml.kernel.org/r/20210716081449.22187-9-sj38.park@xxxxxxxxx
Signed-off-by: SeongJae Park <sjpark@xxxxxxxxx>
Reviewed-by: Fernand Sieber <sieberf@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Amit Shah <amit@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: David Woodhouse <dwmw@xxxxxxxxxx>
Cc: Fan Du <fan.du@xxxxxxxxx>
Cc: Greg Kroah-Hartman <greg@xxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Leonard Foerster <foersleo@xxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Markus Boehme <markubo@xxxxxxxxx>
Cc: Maximilian Heyne <mheyne@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/dbgfs.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-export-kdamond-pid-to-the-user-space
+++ a/mm/damon/dbgfs.c
@@ -239,6 +239,32 @@ out:
return ret;
}
+static ssize_t dbgfs_kdamond_pid_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)
+ len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid);
+ else
+ len = scnprintf(kbuf, count, "none\n");
+ mutex_unlock(&ctx->kdamond_lock);
+ if (!len)
+ goto out;
+ len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
+
+out:
+ kfree(kbuf);
+ return len;
+}
+
static int damon_dbgfs_open(struct inode *inode, struct file *file)
{
file->private_data = inode->i_private;
@@ -258,10 +284,17 @@ static const struct file_operations targ
.write = dbgfs_target_ids_write,
};
+static const struct file_operations kdamond_pid_fops = {
+ .open = damon_dbgfs_open,
+ .read = dbgfs_kdamond_pid_read,
+};
+
static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx)
{
- const char * const file_names[] = {"attrs", "target_ids"};
- const struct file_operations *fops[] = {&attrs_fops, &target_ids_fops};
+ const char * const file_names[] = {"attrs", "target_ids",
+ "kdamond_pid"};
+ const struct file_operations *fops[] = {&attrs_fops, &target_ids_fops,
+ &kdamond_pid_fops};
int i;
for (i = 0; i < ARRAY_SIZE(file_names); i++)
_
Patches currently in -mm which might be from sjpark@xxxxxxxxx are
mm-introduce-data-access-monitor-damon.patch
mm-damon-core-implement-region-based-sampling.patch
mm-damon-adaptively-adjust-regions.patch
mm-idle_page_tracking-make-pg_idle-reusable.patch
mm-damon-implement-primitives-for-the-virtual-memory-address-spaces.patch
mm-damon-add-a-tracepoint.patch
mm-damon-implement-a-debugfs-based-user-space-interface.patch
mm-damon-dbgfs-export-kdamond-pid-to-the-user-space.patch
mm-damon-dbgfs-support-multiple-contexts.patch
documentation-add-documents-for-damon.patch
mm-damon-add-kunit-tests.patch
mm-damon-add-user-space-selftests.patch
maintainers-update-for-damon.patch
