From: Andrew Morton <akpm@linux-foundation.org>
To: Sahitya Tummala <stummala@codeaurora.org>
Cc: Alexander Polakov <apolyakov@beget.ru>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Jan Kara <jack@suse.cz>,
viro@zeniv.linux.org.uk, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock
Date: Thu, 29 Jun 2017 15:48:28 -0700 [thread overview]
Message-ID: <20170629154828.5b4877348470c42352620f41@linux-foundation.org> (raw)
In-Reply-To: <1498707575-2472-1-git-send-email-stummala@codeaurora.org>
On Thu, 29 Jun 2017 09:09:35 +0530 Sahitya Tummala <stummala@codeaurora.org> wrote:
> __list_lru_walk_one() acquires nlru spin lock (nlru->lock) for
> longer duration if there are more number of items in the lru list.
> As per the current code, it can hold the spin lock for upto maximum
> UINT_MAX entries at a time. So if there are more number of items in
> the lru list, then "BUG: spinlock lockup suspected" is observed in
> the below path -
>
> ...
>
> Fix this lockup by reducing the number of entries to be shrinked
> from the lru list to 1024 at once. Also, add cond_resched() before
> processing the lru list again.
>
> ...
>
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -1133,11 +1133,12 @@ void shrink_dcache_sb(struct super_block *sb)
> LIST_HEAD(dispose);
>
> freed = list_lru_walk(&sb->s_dentry_lru,
> - dentry_lru_isolate_shrink, &dispose, UINT_MAX);
> + dentry_lru_isolate_shrink, &dispose, 1024);
>
> this_cpu_sub(nr_dentry_unused, freed);
> shrink_dentry_list(&dispose);
> - } while (freed > 0);
> + cond_resched();
> + } while (list_lru_count(&sb->s_dentry_lru) > 0);
> }
> EXPORT_SYMBOL(shrink_dcache_sb);
I'll add a cc:stable to this one - a large dentry list is a relatively
common thing.
I'm assumng that [1/2] does not need to be backported, OK?
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next prev parent reply other threads:[~2017-06-29 22:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-12 0:47 [PATCH] mm/list_lru.c: use cond_resched_lock() for nlru->lock Sahitya Tummala
2017-06-12 13:11 ` Jan Kara
2017-06-15 21:05 ` Andrew Morton
2017-06-16 14:44 ` Sahitya Tummala
2017-06-17 11:14 ` Vladimir Davydov
2017-06-20 2:52 ` Sahitya Tummala
2017-06-21 6:39 ` [PATCH v2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-21 16:31 ` Vladimir Davydov
2017-06-22 16:31 ` Sahitya Tummala
2017-06-22 17:49 ` Vladimir Davydov
2017-06-28 6:07 ` [PATCH v3 1/2] mm/list_lru.c: fix list_lru_count_node() to be race free Sahitya Tummala
2017-06-28 6:07 ` [PATCH v3 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-28 17:18 ` [PATCH v3 1/2] mm/list_lru.c: fix list_lru_count_node() to be race free Vladimir Davydov
2017-06-29 3:39 ` [PATCH v4 " Sahitya Tummala
2017-07-01 16:28 ` Vladimir Davydov
2017-06-29 3:39 ` [PATCH v4 2/2] fs/dcache.c: fix spin lockup issue on nlru->lock Sahitya Tummala
2017-06-29 22:48 ` Andrew Morton [this message]
2017-06-30 3:16 ` Sahitya Tummala
2017-07-01 16:28 ` Vladimir Davydov
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