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From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org,
	linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org,
	linux-hardening@vger.kernel.org,
	kernel-hardening@lists.openwall.com
Cc: ira.weiny@intel.com, rppt@kernel.org, dan.j.williams@intel.com,
	linux-kernel@vger.kernel.org,
	Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: [PATCH RFC 1/9] list: Support getting most recent element in list_lru
Date: Tue,  4 May 2021 17:30:24 -0700	[thread overview]
Message-ID: <20210505003032.489164-2-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20210505003032.489164-1-rick.p.edgecombe@intel.com>

In future patches, some functionality will use list_lru that also needs
to keep track of the most recently used element on a node. Since this
information is already contained within list_lru, add a function to get
it so that an additional list is not needed in the caller.

Do not support memcg aware list_lru's since it is not needed by the
intended caller.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 include/linux/list_lru.h | 13 +++++++++++++
 mm/list_lru.c            | 28 ++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index 9dcaa3e582c9..4bde44a5024b 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -103,6 +103,19 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item);
  */
 bool list_lru_del(struct list_lru *lru, struct list_head *item);
 
+/**
+ * list_lru_get_mru: gets and removes the tail from one of the node lists
+ * @list_lru: the lru pointer
+ * @nid: the node id
+ *
+ * This function removes the most recently added item from one of the node
+ * id specified. This function should not be used if the list_lru is memcg
+ * aware.
+ *
+ * Return value: The element removed
+ */
+struct list_head *list_lru_get_mru(struct list_lru *lru, int nid);
+
 /**
  * list_lru_count_one: return the number of objects currently held by @lru
  * @lru: the lru pointer.
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 6f067b6b935f..fd5b19dcfc72 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -156,6 +156,34 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
 }
 EXPORT_SYMBOL_GPL(list_lru_del);
 
+struct list_head *list_lru_get_mru(struct list_lru *lru, int nid)
+{
+	struct list_lru_node *nlru = &lru->node[nid];
+	struct list_lru_one *l = &nlru->lru;
+	struct list_head *ret;
+
+	/* This function does not attempt to search through the memcg lists */
+	if (list_lru_memcg_aware(lru)) {
+		WARN_ONCE(1, "list_lru: %s not supported on memcg aware list_lrus", __func__);
+		return NULL;
+	}
+
+	spin_lock(&nlru->lock);
+	if (list_empty(&l->list)) {
+		ret = NULL;
+	} else {
+		/* Get tail */
+		ret = l->list.prev;
+		list_del_init(ret);
+
+		l->nr_items--;
+		nlru->nr_items--;
+	}
+	spin_unlock(&nlru->lock);
+
+	return ret;
+}
+
 void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
 {
 	list_del_init(item);
-- 
2.30.2


  reply	other threads:[~2021-05-05  0:32 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-05  0:30 [PATCH RFC 0/9] PKS write protected page tables Rick Edgecombe
2021-05-05  0:30 ` Rick Edgecombe [this message]
2021-05-05  0:30 ` [PATCH RFC 2/9] list: Support list head not in object for list_lru Rick Edgecombe
2021-05-05  0:30 ` [PATCH RFC 3/9] x86/mm/cpa: Add grouped page allocations Rick Edgecombe
2021-05-05 12:08   ` Mike Rapoport
2021-05-05 13:09     ` Peter Zijlstra
2021-05-05 18:45       ` Mike Rapoport
2021-05-05 21:57         ` Edgecombe, Rick P
2021-05-09  9:39           ` Mike Rapoport
2021-05-10 19:38             ` Edgecombe, Rick P
2021-05-05  0:30 ` [PATCH RFC 4/9] mm: Explicitly zero page table lock ptr Rick Edgecombe
2021-05-05  0:30 ` [PATCH RFC 5/9] x86, mm: Use cache of page tables Rick Edgecombe
2021-05-05  8:51   ` Peter Zijlstra
2021-05-05 12:09     ` Mike Rapoport
2021-05-05 13:19       ` Peter Zijlstra
2021-05-05 21:54         ` Edgecombe, Rick P
2021-05-06 17:59       ` Matthew Wilcox
2021-05-06 18:24   ` Shakeel Butt
2021-05-07 16:27     ` Edgecombe, Rick P
2021-05-05  0:30 ` [PATCH RFC 6/9] x86/mm/cpa: Add set_memory_pks() Rick Edgecombe
2021-05-05  0:30 ` [PATCH RFC 7/9] x86/mm/cpa: Add perm callbacks to grouped pages Rick Edgecombe
2021-05-05  0:30 ` [PATCH RFC 8/9] x86, mm: Protect page tables with PKS Rick Edgecombe
2021-05-05  0:30 ` [PATCH RFC 9/9] x86, cpa: PKS protect direct map page tables Rick Edgecombe
2021-05-05  2:03 ` [PATCH RFC 0/9] PKS write protected " Ira Weiny
2021-05-05  6:25 ` Kees Cook
2021-05-05  8:37   ` Peter Zijlstra
2021-05-05 18:38     ` Kees Cook
2021-05-05 19:51   ` Edgecombe, Rick P
2021-05-06  0:00   ` Ira Weiny
2021-05-05 11:08 ` Vlastimil Babka
2021-05-05 11:56   ` Peter Zijlstra
2021-05-05 19:46     ` Edgecombe, Rick P

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