From: Sahitya Tummala <stummala@codeaurora.org>
To: Alexander Polakov <apolyakov@beget.ru>,
Andrew Morton <akpm@linux-foundation.org>,
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
Cc: Sahitya Tummala <stummala@codeaurora.org>
Subject: [PATCH v4 1/2] mm/list_lru.c: fix list_lru_count_node() to be race free
Date: Thu, 29 Jun 2017 09:09:15 +0530 [thread overview]
Message-ID: <1498707555-30525-1-git-send-email-stummala@codeaurora.org> (raw)
In-Reply-To: <20170628171854.t4sjyjv55j673qzv@esperanza>
list_lru_count_node() iterates over all memcgs to get
the total number of entries on the node but it can race with
memcg_drain_all_list_lrus(), which migrates the entries from
a dead cgroup to another. This can return incorrect number of
entries from list_lru_count_node().
Fix this by keeping track of entries per node and simply return
it in list_lru_count_node().
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
---
include/linux/list_lru.h | 1 +
mm/list_lru.c | 14 ++++++--------
2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index cb0ba9f..fa7fd03 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -44,6 +44,7 @@ struct list_lru_node {
/* for cgroup aware lrus points to per cgroup lists, otherwise NULL */
struct list_lru_memcg *memcg_lrus;
#endif
+ long nr_items;
} ____cacheline_aligned_in_smp;
struct list_lru {
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 234676e..7a40fa2 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -117,6 +117,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item)
l = list_lru_from_kmem(nlru, item);
list_add_tail(item, &l->list);
l->nr_items++;
+ nlru->nr_items++;
spin_unlock(&nlru->lock);
return true;
}
@@ -136,6 +137,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
l = list_lru_from_kmem(nlru, item);
list_del_init(item);
l->nr_items--;
+ nlru->nr_items--;
spin_unlock(&nlru->lock);
return true;
}
@@ -183,15 +185,10 @@ unsigned long list_lru_count_one(struct list_lru *lru,
unsigned long list_lru_count_node(struct list_lru *lru, int nid)
{
- long count = 0;
- int memcg_idx;
+ struct list_lru_node *nlru;
- count += __list_lru_count_one(lru, nid, -1);
- if (list_lru_memcg_aware(lru)) {
- for_each_memcg_cache_index(memcg_idx)
- count += __list_lru_count_one(lru, nid, memcg_idx);
- }
- return count;
+ nlru = &lru->node[nid];
+ return nlru->nr_items;
}
EXPORT_SYMBOL_GPL(list_lru_count_node);
@@ -226,6 +223,7 @@ unsigned long list_lru_count_node(struct list_lru *lru, int nid)
assert_spin_locked(&nlru->lock);
case LRU_REMOVED:
isolated++;
+ nlru->nr_items--;
/*
* If the lru lock has been dropped, our list
* traversal is now invalid and so we have to
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-06-29 3:39 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 ` Sahitya Tummala [this message]
2017-07-01 16:28 ` [PATCH v4 " 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
2017-06-30 3:16 ` Sahitya Tummala
2017-07-01 16:28 ` Vladimir Davydov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1498707555-30525-1-git-send-email-stummala@codeaurora.org \
--to=stummala@codeaurora.org \
--cc=akpm@linux-foundation.org \
--cc=apolyakov@beget.ru \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=vdavydov.dev@gmail.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).