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Message-ID: <20201216084404.23183-5-sjpark@amazon.com>
Date: Wed, 16 Dec 2020 09:44:00 +0100
From: SeongJae Park <sjpark@...zon.com>
To: <akpm@...ux-foundation.org>
CC: SeongJae Park <sjpark@...zon.de>, <Jonathan.Cameron@...wei.com>,
<aarcange@...hat.com>, <acme@...nel.org>,
<alexander.shishkin@...ux.intel.com>, <amit@...nel.org>,
<benh@...nel.crashing.org>, <brendan.d.gregg@...il.com>,
<brendanhiggins@...gle.com>, <cai@....pw>,
<colin.king@...onical.com>, <corbet@....net>, <david@...hat.com>,
<dwmw@...zon.com>, <elver@...gle.com>, <fan.du@...el.com>,
<foersleo@...zon.de>, <gthelen@...gle.com>, <irogers@...gle.com>,
<jolsa@...hat.com>, <kirill@...temov.name>, <mark.rutland@....com>,
<mgorman@...e.de>, <minchan@...nel.org>, <mingo@...hat.com>,
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<rdunlap@...radead.org>, <riel@...riel.com>, <rientjes@...gle.com>,
<rostedt@...dmis.org>, <rppt@...nel.org>, <sblbir@...zon.com>,
<shakeelb@...gle.com>, <shuah@...nel.org>, <sj38.park@...il.com>,
<snu@...zon.de>, <vbabka@...e.cz>, <vdavydov.dev@...il.com>,
<yang.shi@...ux.alibaba.com>, <ying.huang@...el.com>,
<zgf574564920@...il.com>, <linux-damon@...zon.com>,
<linux-mm@...ck.org>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: [RFC v15.1 4/8] mm/damon/dbgfs: Support DAMON-based Operation Schemes
From: SeongJae Park <sjpark@...zon.de>
This commit makes 'damon-dbgfs' to support the data access monitoring
oriented memory management schemes. Users can read and update the
schemes using ``<debugfs>/damon/schemes`` file. The format is::
<min/max size> <min/max access frequency> <min/max age> <action>
Signed-off-by: SeongJae Park <sjpark@...zon.de>
---
mm/damon/dbgfs.c | 169 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 165 insertions(+), 4 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 7380c6502f3d..10ce8e8786cb 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -219,6 +219,159 @@ static ssize_t dbgfs_record_write(struct file *file,
return ret;
}
+static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len)
+{
+ struct damos *s;
+ int written = 0;
+ int rc;
+
+ damon_for_each_scheme(s, c) {
+ rc = scnprintf(&buf[written], len - written,
+ "%lu %lu %u %u %u %u %d\n",
+ s->min_sz_region, s->max_sz_region,
+ s->min_nr_accesses, s->max_nr_accesses,
+ s->min_age_region, s->max_age_region,
+ s->action);
+ if (!rc)
+ return -ENOMEM;
+
+ written += rc;
+ }
+ return written;
+}
+
+static ssize_t dbgfs_schemes_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);
+ len = sprint_schemes(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 void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes)
+{
+ ssize_t i;
+
+ for (i = 0; i < nr_schemes; i++)
+ kfree(schemes[i]);
+ kfree(schemes);
+}
+
+static bool damos_action_valid(int action)
+{
+ switch (action) {
+ case DAMOS_WILLNEED:
+ case DAMOS_COLD:
+ case DAMOS_PAGEOUT:
+ case DAMOS_HUGEPAGE:
+ case DAMOS_NOHUGEPAGE:
+ return true;
+ default:
+ return false;
+ }
+}
+
+/*
+ * Converts a string into an array of struct damos pointers
+ *
+ * Returns an array of struct damos pointers that converted if the conversion
+ * success, or NULL otherwise.
+ */
+static struct damos **str_to_schemes(const char *str, ssize_t len,
+ ssize_t *nr_schemes)
+{
+ struct damos *scheme, **schemes;
+ const int max_nr_schemes = 256;
+ int pos = 0, parsed, ret;
+ unsigned long min_sz, max_sz;
+ unsigned int min_nr_a, max_nr_a, min_age, max_age;
+ unsigned int action;
+
+ schemes = kmalloc_array(max_nr_schemes, sizeof(scheme),
+ GFP_KERNEL);
+ if (!schemes)
+ return NULL;
+
+ *nr_schemes = 0;
+ while (pos < len && *nr_schemes < max_nr_schemes) {
+ ret = sscanf(&str[pos], "%lu %lu %u %u %u %u %u%n",
+ &min_sz, &max_sz, &min_nr_a, &max_nr_a,
+ &min_age, &max_age, &action, &parsed);
+ if (ret != 7)
+ break;
+ if (!damos_action_valid(action)) {
+ pr_err("wrong action %d\n", action);
+ goto fail;
+ }
+
+ pos += parsed;
+ scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a,
+ min_age, max_age, action);
+ if (!scheme)
+ goto fail;
+
+ schemes[*nr_schemes] = scheme;
+ *nr_schemes += 1;
+ }
+ return schemes;
+fail:
+ free_schemes_arr(schemes, *nr_schemes);
+ return NULL;
+}
+
+static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct damon_ctx *ctx = file->private_data;
+ char *kbuf;
+ struct damos **schemes;
+ ssize_t nr_schemes = 0, ret = count;
+ int err;
+
+ kbuf = user_input_str(buf, count, ppos);
+ if (IS_ERR(kbuf))
+ return PTR_ERR(kbuf);
+
+ schemes = str_to_schemes(kbuf, ret, &nr_schemes);
+ if (!schemes) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ mutex_lock(&ctx->kdamond_lock);
+ if (ctx->kdamond) {
+ ret = -EBUSY;
+ goto unlock_out;
+ }
+
+ err = damon_set_schemes(ctx, schemes, nr_schemes);
+ if (err)
+ ret = err;
+ else
+ nr_schemes = 0;
+unlock_out:
+ mutex_unlock(&ctx->kdamond_lock);
+ free_schemes_arr(schemes, nr_schemes);
+out:
+ kfree(kbuf);
+ return ret;
+}
+
#define targetid_is_pid(ctx) \
(ctx->primitive.target_valid == damon_va_target_valid)
@@ -385,6 +538,13 @@ static const struct file_operations record_fops = {
.write = dbgfs_record_write,
};
+static const struct file_operations schemes_fops = {
+ .owner = THIS_MODULE,
+ .open = damon_dbgfs_open,
+ .read = dbgfs_schemes_read,
+ .write = dbgfs_schemes_write,
+};
+
static const struct file_operations target_ids_fops = {
.owner = THIS_MODULE,
.open = damon_dbgfs_open,
@@ -400,10 +560,11 @@ static const struct file_operations kdamond_pid_fops = {
static int dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx)
{
- const char * const file_names[] = {"attrs", "record", "target_ids",
- "kdamond_pid"};
- const struct file_operations *fops[] = {&attrs_fops, &record_fops,
- &target_ids_fops, &kdamond_pid_fops};
+ const char * const file_names[] = {"attrs", "record", "schemes",
+ "target_ids", "kdamond_pid"};
+ const struct file_operations *fops[] = {&attrs_fops,
+ &record_fops, &schemes_fops, &target_ids_fops,
+ &kdamond_pid_fops};
int i;
for (i = 0; i < ARRAY_SIZE(file_names); i++) {
--
2.17.1
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