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From:   sj@kernel.org
To:     akpm@linux-foundation.org
Cc:     linux-damon@amazon.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, SeongJae Park <sj@kernel.org>
Subject: [PATCH 2/3] mm/damon/sysfs: support fixed virtual address ranges monitoring
Date:   Tue, 26 Apr 2022 23:17:49 +0000
Message-Id: <20220426231750.48822-3-sj@kernel.org>
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From: SeongJae Park <sj@kernel.org>

This commit makes DAMON sysfs interface to support the fixed virtual
address ranges monitoring.  After this commit, writing 'fvaddr' to the
'operations' DAMON sysfs file makes DAMON uses the monitoring operations
set for fixed virtual address ranges, so that users can monitor accesses
to only interested virtual address ranges.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 719a286d378f..767ab8c33e4d 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1694,7 +1694,7 @@ static struct kobj_type damon_sysfs_attrs_ktype = {
 /* This should match with enum damon_ops_id */
 static const char * const damon_sysfs_ops_strs[] = {
 	"vaddr",
-	"unsupported",	/* fvaddr is not supported by sysfs yet */
+	"fvaddr",
 	"paddr",
 };
 
@@ -1844,9 +1844,6 @@ static ssize_t operations_store(struct kobject *kobj,
 
 	for (id = 0; id < NR_DAMON_OPS; id++) {
 		if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
-			/* fvaddr is not supported by sysfs yet */
-			if (id == DAMON_OPS_FVADDR)
-				return -EINVAL;
 			context->ops_id = id;
 			return count;
 		}
@@ -2136,7 +2133,8 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
 			damon_sysfs_destroy_targets(ctx);
 			return -ENOMEM;
 		}
-		if (ctx->ops.id == DAMON_OPS_VADDR) {
+		if (ctx->ops.id == DAMON_OPS_VADDR ||
+				ctx->ops.id == DAMON_OPS_FVADDR) {
 			t->pid = find_get_pid(sys_target->pid);
 			if (!t->pid) {
 				damon_sysfs_destroy_targets(ctx);
-- 
2.25.1