Attachment 868747 Details for Bug 1212906

[patch] [PATCH] fanotify23: Make evictable marks tests more reliable

0001-fanotify23-Make-evictable-marks-tests-more-reliable.patch (text/plain), 2.14 KB, created by Jan Kara on 2023-08-10 13:07:56 UTC

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Creator: Jan Kara

Created: 2023-08-10 13:07:56 UTC

Size: 2.14 KB

patch

obsolete

>From 7a9f975fca34971f77c711d465636129993a9f0c Mon Sep 17 00:00:00 2001
>From: Jan Kara <jack@suse.cz>
>Date: Thu, 10 Aug 2023 14:57:08 +0200
>Subject: [PATCH] fanotify23: Make evictable marks tests more reliable
>
>It has been observed that when fanotify23 test is run in a loop, it
>eventually fails as:
>
>fanotify23.c:112: TPASS: FAN_MARK_ADD failed with EEXIST as expected when trying to downgrade to evictable mark
>fanotify23.c:75: TPASS: FAN_MARK_REMOVE failed with ENOENT as expected after empty mask
>fanotify23.c:156: TPASS: Got no events as expected
>fanotify23.c:81: TFAIL: FAN_MARK_REMOVE did not fail with ENOENT as expected after drop_caches: SUCCESS (0)
>
>This is because repeated evictions of caches done by the test reclaim
>all freeable slab objects in the system. So when the test calls drop
>caches, only the dentry and inode of the test file are there to reclaim.
>But for inode to be reclaimed, dentry (which holds inode reference) has
>to be freed first and for dentry to be freed it has to first cycle
>through the LRU which takes two slab reclaim calls.
>
>Call drop caches twice to make sure dentry has chance to pass through
>the LRU and be reclaimed.
>
>Signed-off-by: Jan Kara <jack@suse.cz>
>---
> testcases/kernel/syscalls/fanotify/fanotify23.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
>diff --git a/testcases/kernel/syscalls/fanotify/fanotify23.c b/testcases/kernel/syscalls/fanotify/fanotify23.c
>index 89fd4f36a09b..2d50f70585b7 100644
>--- a/testcases/kernel/syscalls/fanotify/fanotify23.c
>+++ b/testcases/kernel/syscalls/fanotify/fanotify23.c
>@@ -160,10 +160,15 @@ static void test_fanotify(void)
> 	}
> 
> 	/*
>-	 * drop_caches should evict inode from cache and remove evictable mark
>+	 * drop_caches should evict inode from cache and remove evictable mark.
>+	 * We call drop_caches twice as once the dentries will just cycle
>+	 * through the LRU without being reclaimed and if there are no other
>+	 * objects to reclaim, the slab reclaim will just stop instead of
>+	 * retrying.
> 	 */
> 	fsync_file(TEST_FILE);
> 	SAFE_FILE_PRINTF(DROP_CACHES_FILE, "3");
>+	SAFE_FILE_PRINTF(DROP_CACHES_FILE, "3");
> 
> 	verify_mark_removed(TEST_FILE, "after drop_caches");
> 
>-- 
>2.35.3
>

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