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From: SeongJae Park <sjpark@amazon.com>
To: <akpm@linux-foundation.org>
Cc: SeongJae Park <sjpark@amazon.de>, <Jonathan.Cameron@Huawei.com>,
	<aarcange@redhat.com>, <acme@kernel.org>,
	<alexander.shishkin@linux.intel.com>, <amit@kernel.org>,
	<benh@kernel.crashing.org>, <brendan.d.gregg@gmail.com>,
	<brendanhiggins@google.com>, <cai@lca.pw>,
	<colin.king@canonical.com>, <corbet@lwn.net>, <david@redhat.com>,
	<dwmw@amazon.com>, <fan.du@intel.com>, <foersleo@amazon.de>,
	<gthelen@google.com>, <irogers@google.com>, <jolsa@redhat.com>,
	<kirill@shutemov.name>, <mark.rutland@arm.com>, <mgorman@suse.de>,
	<minchan@kernel.org>, <mingo@redhat.com>, <namhyung@kernel.org>,
	<peterz@infradead.org>, <rdunlap@infradead.org>,
	<riel@surriel.com>, <rientjes@google.com>, <rostedt@goodmis.org>,
	<rppt@kernel.org>, <sblbir@amazon.com>, <shakeelb@google.com>,
	<shuah@kernel.org>, <sj38.park@gmail.com>, <snu@amazon.de>,
	<vbabka@suse.cz>, <vdavydov.dev@gmail.com>,
	<yang.shi@linux.alibaba.com>, <ying.huang@intel.com>,
	<zgf574564920@gmail.com>, <linux-damon@amazon.com>,
	<linux-mm@kvack.org>, <linux-doc@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: [RFC v8 01/10] mm/damon/debugfs: Allow users to set initial monitoring target regions
Date: Mon, 31 Aug 2020 12:47:21 +0200	[thread overview]
Message-ID: <20200831104730.28970-2-sjpark@amazon.com> (raw)
In-Reply-To: <20200831104730.28970-1-sjpark@amazon.com>

From: SeongJae Park <sjpark@amazon.de>

Some users would want to monitor only a part of the entire virtual
memory address space.  The '->init_target_regions' callback is therefore
provided, but only programming interface can use it.

For the reason, this commit introduces a new debugfs file,
'init_region'.  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 below form:

    <pid> <start address> <end address>

This commit also makes the default '->init_target_regions' callback,
'kdamon_init_vm_regions()' to do nothing if the user has set the initial
target regions already.

Note that the regions will be updated to cover entire memory mapped
regions after 'regions update interval'.  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.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
---
 mm/damon.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 152 insertions(+), 4 deletions(-)

diff --git a/mm/damon.c b/mm/damon.c
index 7e3c8c82a010..9815d22fc4de 100644
--- a/mm/damon.c
+++ b/mm/damon.c
@@ -2001,6 +2001,147 @@ static ssize_t debugfs_record_write(struct file *file,
 	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 = snprintf(&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 debugfs_init_regions_read(struct file *file, char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	struct damon_ctx *ctx = &damon_user_ctx;
+	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);
+		return -EBUSY;
+	}
+
+	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;
+	int rc = -EINVAL;
+
+	if (ar->start >= ar->end)
+		return -EINVAL;
+
+	damon_for_each_target(t, c) {
+		if (t->id == target_id) {
+			r = damon_new_region(ar->start, ar->end);
+			if (!r)
+				return -ENOMEM;
+			damon_add_region(r, t);
+			if (nr_damon_regions(t) > 1) {
+				prev = damon_prev_region(r);
+				if (prev->ar.end > r->ar.start) {
+					damon_destroy_region(r);
+					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);
+	}
+
+	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);
+	}
+	return err;
+}
+
+static ssize_t debugfs_init_regions_write(struct file *file,
+					  const char __user *buf, size_t count,
+					  loff_t *ppos)
+{
+	struct damon_ctx *ctx = &damon_user_ctx;
+	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 debugfs_attrs_read(struct file *file,
 		char __user *buf, size_t count, loff_t *ppos)
 {
@@ -2077,6 +2218,12 @@ static const struct file_operations record_fops = {
 	.write = debugfs_record_write,
 };
 
+static const struct file_operations init_regions_fops = {
+	.owner = THIS_MODULE,
+	.read = debugfs_init_regions_read,
+	.write = debugfs_init_regions_write,
+};
+
 static const struct file_operations attrs_fops = {
 	.owner = THIS_MODULE,
 	.read = debugfs_attrs_read,
@@ -2087,10 +2234,11 @@ static struct dentry *debugfs_root;
 
 static int __init damon_debugfs_init(void)
 {
-	const char * const file_names[] = {"attrs", "record", "schemes",
-		"target_ids", "monitor_on"};
-	const struct file_operations *fops[] = {&attrs_fops, &record_fops,
-		&schemes_fops, &target_ids_fops, &monitor_on_fops};
+	const char * const file_names[] = {"attrs", "init_regions", "record",
+		"schemes", "target_ids", "monitor_on"};
+	const struct file_operations *fops[] = {&attrs_fops,
+		&init_regions_fops, &record_fops, &schemes_fops,
+		&target_ids_fops, &monitor_on_fops};
 	int i;
 
 	debugfs_root = debugfs_create_dir("damon", NULL);
-- 
2.17.1



  reply	other threads:[~2020-08-31 10:48 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-31 10:47 [RFC v8 00/10] DAMON: Support Physical Memory Address Space Monitoring SeongJae Park
2020-08-31 10:47 ` SeongJae Park [this message]
2020-08-31 18:08   ` [RFC v8 01/10] mm/damon/debugfs: Allow users to set initial monitoring target regions Marco Elver
2020-09-01  6:35     ` SeongJae Park
2020-08-31 10:47 ` [RFC v8 02/10] tools/damon: Support init target regions specification SeongJae Park
2020-08-31 10:47 ` [RFC v8 03/10] mm/damon-test: Add more unit tests for 'init_regions' SeongJae Park
2020-08-31 10:47 ` [RFC v8 04/10] selftests/damon/_chk_record: Do not check number of gaps SeongJae Park
2020-08-31 10:47 ` [RFC v8 05/10] Docs/admin-guide/mm/damon: Document 'init_regions' feature SeongJae Park
2020-08-31 10:47 ` [RFC v8 06/10] mm/damon: Implement callbacks for physical memory monitoring SeongJae Park
2020-08-31 10:47 ` [RFC v8 07/10] mm/damon/debugfs: Support " SeongJae Park
2020-08-31 10:47 ` [RFC v8 08/10] tools/damon/record: " SeongJae Park
2020-08-31 10:47 ` [RFC v8 09/10] tools/damon/record: Support NUMA specific recording SeongJae Park
2020-08-31 10:47 ` [RFC v8 10/10] Docs/DAMON: Document physical memory monitoring support SeongJae Park
2020-09-01  6:37 ` [RFC v8 00/10] DAMON: Support Physical Memory Address Space Monitoring SeongJae Park

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