From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Ying Huang <ying.huang@intel.com>,
linux-mm@kvack.org, akpm@linux-foundation.org
Cc: Wei Xu <weixugc@google.com>, Greg Thelen <gthelen@google.com>,
Yang Shi <shy828301@gmail.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Tim C Chen <tim.c.chen@intel.com>,
Brice Goglin <brice.goglin@gmail.com>,
Michal Hocko <mhocko@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Hesham Almatary <hesham.almatary@huawei.com>,
Dave Hansen <dave.hansen@intel.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Alistair Popple <apopple@nvidia.com>,
Dan Williams <dan.j.williams@intel.com>,
Feng Tang <feng.tang@intel.com>,
Jagdish Gediya <jvgediya@linux.ibm.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
David Rientjes <rientjes@google.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v6 01/13] mm/demotion: Add support for explicit memory tiers
Date: Tue, 14 Jun 2022 13:50:29 +0530 [thread overview]
Message-ID: <87a6afmzaq.fsf@linux.ibm.com> (raw)
In-Reply-To: <a88bd25fc77252dee4f895f3a9b2c1f6ebb5169e.camel@intel.com>
Ying Huang <ying.huang@intel.com> writes:
....
>
>> All those functions are called with memory_tier_lock_held. Infact all
>> list operations requires that lock held. What details do you suggest we
>> document? I can add extra comment to the mutex itself? Adding locking
>> details to all the functions will be duplicating the same details at
>> multiple places?
>
> memory_tier_lock isn't held to call register_memory_tier() in this
> patch. That will cause confusion.
will this help to explain this better
modified mm/memory-tiers.c
@@ -151,6 +151,11 @@ static void insert_memory_tier(struct memory_tier *memtier)
struct list_head *ent;
struct memory_tier *tmp_memtier;
+ if (IS_ENABLED(CONFIG_DEBUG_VM) && !mutex_is_locked(&memory_tier_lock)) {
+ WARN_ON_ONCE(1);
+ return;
+ }
+
list_for_each(ent, &memory_tiers) {
tmp_memtier = list_entry(ent, struct memory_tier, list);
if (tmp_memtier->rank < memtier->rank) {
@@ -811,8 +816,12 @@ static int __init memory_tier_init(void)
/*
* Register only default memory tier to hide all empty
- * memory tier from sysfs.
+ * memory tier from sysfs. Since this is early during
+ * boot, we could avoid holding memtory_tier_lock. But
+ * keep it simple by holding locks. We can add lock
+ * held debug checks in other functions.
*/
+ mutex_lock(&memory_tier_lock);
memtier = register_memory_tier(DEFAULT_MEMORY_TIER,
get_rank_from_tier(DEFAULT_MEMORY_TIER));
@@ -828,6 +837,7 @@ static int __init memory_tier_init(void)
NODE_DATA(node)->memtier = memtier;
node_set(node, memtier->nodelist);
}
+ mutex_unlock(&memory_tier_lock);
migrate_on_reclaim_init();
return 0;
-aneesh
next prev parent reply other threads:[~2022-06-14 8:20 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 13:52 [PATCH v6 00/13] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 01/13] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
2022-06-13 3:22 ` Ying Huang
2022-06-13 3:31 ` Aneesh Kumar K V
2022-06-13 5:30 ` Ying Huang
2022-06-13 13:16 ` Johannes Weiner
2022-06-13 13:28 ` Aneesh Kumar K V
2022-06-14 8:20 ` Aneesh Kumar K.V [this message]
2022-06-14 15:13 ` Davidlohr Bueso
2022-06-10 13:52 ` [PATCH v6 02/13] mm/demotion: Move memory demotion related code Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 03/13] mm/demotion: Return error on write to numa_demotion sysfs Aneesh Kumar K.V
2022-06-13 3:26 ` Ying Huang
2022-06-13 3:35 ` Aneesh Kumar K V
2022-06-13 5:33 ` Ying Huang
2022-06-13 5:48 ` Aneesh Kumar K V
2022-06-14 8:40 ` Ying Huang
2022-06-10 13:52 ` [PATCH v6 04/13] mm/demotion/dax/kmem: Set node's memory tier to MEMORY_TIER_PMEM Aneesh Kumar K.V
2022-06-13 6:59 ` Ying Huang
2022-06-13 7:05 ` Aneesh Kumar K V
2022-06-10 13:52 ` [PATCH v6 05/13] mm/demotion: Build demotion targets based on explicit memory tiers Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 06/13] mm/demotion: Expose memory tier details via sysfs Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 07/13] mm/demotion: Add per node memory tier attribute to sysfs Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 08/13] mm/demotion: Add support for memory tier creation from userspace Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 09/13] mm/demotion: Add pg_data_t member to track node memory tier details Aneesh Kumar K.V
2022-06-13 7:07 ` Ying Huang
2022-06-10 13:52 ` [PATCH v6 10/13] mm/demotion: Demote pages according to allocation fallback order Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 11/13] mm/demotion: Update node_is_toptier to work with memory tiers Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 12/13] mm/demotion: Add documentation for memory tiering Aneesh Kumar K.V
2022-06-10 13:52 ` [PATCH v6 13/13] mm/demotion: Add sysfs ABI documentation Aneesh Kumar K.V
-- strict thread matches above, loose matches on Subject: below --
2022-06-10 13:49 [PATCH v6 00/13] mm/demotion: Memory tiers and demotion Aneesh Kumar K.V
2022-06-10 13:49 ` [PATCH v6 01/13] mm/demotion: Add support for explicit memory tiers Aneesh Kumar K.V
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