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From: "Ho-Ren (Jack) Chuang" Message-ID: <970686ea8a7aba6f5daa752a39609f5ab7a48a06@linux.dev> TLS-Required: No Subject: Re: [PATCH v2 1/1] memory tier: consolidate the initialization of memory tiers To: "Huang, Ying" Cc: "Jonathan Cameron" , "Gregory Price" , aneesh.kumar@linux.ibm.com, mhocko@suse.com, tj@kernel.org, john@jagalactic.com, "Eishan Mirakhur" , "Vinicius Tavares Petrucci" , "Ravis OpenSrc" , "Alistair Popple" , "Srinivasulu Thanneeru" , "SeongJae Park" , "Rafael J. Wysocki" , "Len Brown" , "Andrew Morton" , "Dave Jiang" , "Dan Williams" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Ho-Ren (Jack) Chuang" , "Ho-Ren (Jack) Chuang" , "Ho-Ren (Jack) Chuang" , linux-cxl@vger.kernel.org, qemu-devel@nongnu.org In-Reply-To: <87tth9ofsi.fsf@yhuang6-desk2.ccr.corp.intel.com> References: <20240628060925.303309-1-horen.chuang@linux.dev> <20240628060925.303309-2-horen.chuang@linux.dev> <87tth9ofsi.fsf@yhuang6-desk2.ccr.corp.intel.com> X-Migadu-Flow: FLOW_OUT Received-SPF: pass client-ip=91.218.175.183; envelope-from=horen.chuang@linux.dev; helo=out-183.mta0.migadu.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Huang, Ying, Thanks for your feedback and helpful suggestions. Replies inlined. June 30, 2024 at 10:13 PM, "Huang, Ying" wrote: >=20 >=20Hi, Jack, >=20 >=20"Ho-Ren (Jack) Chuang" writes: >=20 >=20I suggest you to merge the [0/1] with the change log here. [0/1] >=20 >=20describes why do we need the patch. The below text describes some >=20 >=20details. Just don't use "---" to separate them. We need both parts in >=20 >=20the final commit message. >=20 Sounds=20good! I will merge them into 1 patch in the v3. > >=20 >=20> If we simply move the set_node_memory_tier() from memory_tier_init(= ) > >=20 >=20> to late_initcall(), it will result in HMAT not registering > >=20 >=20> the mt_adistance_algorithm callback function, because > >=20 >=20> set_node_memory_tier() is not performed during the memory tiering > >=20 >=20> initialization phase, leading to a lack of correct default_dram > >=20 >=20> information. > >=20 >=20> Therefore, we introduced a nodemask to pass the information of the > >=20 >=20> default DRAM nodes. The reason for not choosing to reuse > >=20 >=20> default_dram_type->nodes is that it is not clean enough. So in the= end, > >=20 >=20> we use a __initdata variable, which is a variable that is released= once > >=20 >=20> initialization is complete, including both CPU and memory nodes fo= r HMAT > >=20 >=20> to iterate through. > >=20 >=20> Besides, since default_dram_type may be checked/used during the > >=20 >=20> initialization process of HMAT and drivers, it is better to keep t= he > >=20 >=20> allocation of default_dram_type in memory_tier_init(). > >=20 >=20 > Why do we need it? IIRC, we have deleted its usage in hmat.c. >=20 Although=20default_dram_type is still used in set_node_memory_tier(), I can totally remove this description to remove confusion. > >=20 >=20> Signed-off-by: Ho-Ren (Jack) Chuang > >=20 >=20> Suggested-by: Jonathan Cameron > >=20 >=20> --- > >=20 >=20> drivers/acpi/numa/hmat.c | 5 +-- > >=20 >=20> include/linux/memory-tiers.h | 2 ++ > >=20 >=20> mm/memory-tiers.c | 59 +++++++++++++++--------------------- > >=20 >=20> 3 files changed, 28 insertions(+), 38 deletions(-) > >=20 >=20> diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > >=20 >=20> index 2c8ccc91ebe6..a2f9e7a4b479 100644 > >=20 >=20> --- a/drivers/acpi/numa/hmat.c > >=20 >=20> +++ b/drivers/acpi/numa/hmat.c > >=20 >=20> @@ -940,10 +940,7 @@ static int hmat_set_default_dram_perf(void) > >=20 >=20> struct memory_target *target; > >=20 >=20> struct access_coordinate *attrs; > >=20 >=20>=20=20 >=20>=20 >=20> - if (!default_dram_type) > >=20 >=20> - return -EIO; > >=20 >=20> - > >=20 >=20> - for_each_node_mask(nid, default_dram_type->nodes) { > >=20 >=20> + for_each_node_mask(nid, default_dram_nodes) { > >=20 >=20> pxm =3D node_to_pxm(nid); > >=20 >=20> target =3D find_mem_target(pxm); > >=20 >=20> if (!target) > >=20 >=20> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-t= iers.h > >=20 >=20> index 0d70788558f4..fa61ad9c4d75 100644 > >=20 >=20> --- a/include/linux/memory-tiers.h > >=20 >=20> +++ b/include/linux/memory-tiers.h > >=20 >=20> @@ -38,6 +38,7 @@ struct access_coordinate; > >=20 >=20> #ifdef CONFIG_NUMA > >=20 >=20> extern bool numa_demotion_enabled; > >=20 >=20> extern struct memory_dev_type *default_dram_type; > >=20 >=20 > Can we remove the above line? >=20 Yes,=20you are right. Good catch, thanks! Will remove it in the v3. > >=20 >=20> +extern nodemask_t default_dram_nodes __initdata; > >=20 >=20 > We don't need to use __initdata in variable declaration. >=20 Thank=20you for your guidance! Will remove __initdata it in the v3. > >=20 >=20> struct memory_dev_type *alloc_memory_type(int adistance); > >=20 >=20> void put_memory_type(struct memory_dev_type *memtype); > >=20 >=20> void init_node_memory_type(int node, struct memory_dev_type *defau= lt_type); > >=20 >=20> @@ -76,6 +77,7 @@ static inline bool node_is_toptier(int node) > >=20 >=20>=20=20 >=20>=20 >=20> #define numa_demotion_enabled false > >=20 >=20> #define default_dram_type NULL > >=20 >=20> +#define default_dram_nodes NODE_MASK_NONE > >=20 >=20 > Should we use after "default_dram_nodes"? >=20 Yes,=20thanks for the reminder. Will fix it in the v3. > >=20 >=20> /* > >=20 >=20> * CONFIG_NUMA implementation returns non NULL error. > >=20 >=20> */ > >=20 >=20> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > >=20 >=20> index 6632102bd5c9..a19a90c3ad36 100644 > >=20 >=20> --- a/mm/memory-tiers.c > >=20 >=20> +++ b/mm/memory-tiers.c > >=20 >=20> @@ -43,6 +43,7 @@ static LIST_HEAD(memory_tiers); > >=20 >=20> static LIST_HEAD(default_memory_types); > >=20 >=20> static struct node_memory_type_map node_memory_types[MAX_NUMNODES]= ; > >=20 >=20> struct memory_dev_type *default_dram_type; > >=20 >=20> +nodemask_t default_dram_nodes __initdata =3D NODE_MASK_NONE; > >=20 >=20>=20=20 >=20>=20 >=20> static const struct bus_type memory_tier_subsys =3D { > >=20 >=20> .name =3D "memory_tiering", > >=20 >=20> @@ -671,28 +672,38 @@ EXPORT_SYMBOL_GPL(mt_put_memory_types); > >=20 >=20>=20=20 >=20>=20 >=20> /* > >=20 >=20> * This is invoked via `late_initcall()` to initialize memory tiers= for > >=20 >=20> - * CPU-less memory nodes after driver initialization, which is > >=20 >=20> - * expected to provide `adistance` algorithms. > >=20 >=20> + * memory nodes, both with and without CPUs. After the initializa= tion of > >=20 >=20> + * firmware and devices, adistance algorithms are expected to be = provided. > >=20 >=20> */ > >=20 >=20> static int __init memory_tier_late_init(void) > >=20 >=20> { > >=20 >=20> int nid; > >=20 >=20> + struct memory_tier *memtier; > >=20 >=20>=20=20 >=20>=20 >=20> + get_online_mems(); > >=20 >=20> guard(mutex)(&memory_tier_lock); > >=20 >=20> + /* > >=20 >=20> + * Look at all the existing and uninitialized N_MEMORY nodes and > >=20 >=20> + * add them to default memory tier or to a tier if we already hav= e > >=20 >=20> + * memory types assigned. > >=20 >=20> + */ > >=20 >=20 > If the memory type of the node has been assigned, we will skip it in th= e >=20 >=20following code. So, I think that we need to revise the comments. >=20 You=20are right, the new version in the v3 will be: /* Assign each uninitialized N_MEMORY node to a memory tier. */ > >=20 >=20> for_each_node_state(nid, N_MEMORY) { > >=20 >=20> /* > >=20 >=20> - * Some device drivers may have initialized memory tiers > >=20 >=20> - * between `memory_tier_init()` and `memory_tier_late_init()`, > >=20 >=20> - * potentially bringing online memory nodes and > >=20 >=20> - * configuring memory tiers. Exclude them here. > >=20 >=20> + * Some device drivers may have initialized > >=20 >=20> + * memory tiers, potentially bringing memory nodes > >=20 >=20> + * online and configuring memory tiers. > >=20 >=20> + * Exclude them here. > >=20 >=20> */ > >=20 >=20> if (node_memory_types[nid].memtype) > >=20 >=20> continue; > >=20 >=20>=20=20 >=20>=20 >=20> - set_node_memory_tier(nid); > >=20 >=20> + memtier =3D set_node_memory_tier(nid); > >=20 >=20> + if (IS_ERR(memtier)) > >=20 >=20> + /* Continue with memtiers we are able to setup. */ > >=20 >=20> + break; > >=20 >=20> } > >=20 >=20> - > >=20 >=20> establish_demotion_targets(); > >=20 >=20> + put_online_mems(); > >=20 >=20>=20=20 >=20>=20 >=20> return 0; > >=20 >=20> } > >=20 >=20> @@ -875,8 +886,7 @@ static int __meminit memtier_hotplug_callback(= struct notifier_block *self, > >=20 >=20>=20=20 >=20>=20 >=20> static int __init memory_tier_init(void) > >=20 >=20> { > >=20 >=20> - int ret, node; > >=20 >=20> - struct memory_tier *memtier; > >=20 >=20> + int ret; > >=20 >=20>=20=20 >=20>=20 >=20> ret =3D subsys_virtual_register(&memory_tier_subsys, NULL); > >=20 >=20> if (ret) > >=20 >=20> @@ -887,7 +897,8 @@ static int __init memory_tier_init(void) > >=20 >=20> GFP_KERNEL); > >=20 >=20> WARN_ON(!node_demotion); > >=20 >=20> #endif > >=20 >=20> - mutex_lock(&memory_tier_lock); > >=20 >=20> + > >=20 >=20> + guard(mutex)(&memory_tier_lock); > >=20 >=20> /* > >=20 >=20> * For now we can have 4 faster memory tiers with smaller adistance > >=20 >=20> * than default DRAM tier. > >=20 >=20> @@ -897,29 +908,9 @@ static int __init memory_tier_init(void) > >=20 >=20> if (IS_ERR(default_dram_type)) > >=20 >=20> panic("%s() failed to allocate default DRAM tier\n", __func__);=0D > >=20 >=20>=20=20 >=20>=20 >=20> - /* > >=20 >=20> - * Look at all the existing N_MEMORY nodes and add them to > >=20 >=20> - * default memory tier or to a tier if we already have memory > >=20 >=20> - * types assigned. > >=20 >=20> - */ > >=20 >=20> - for_each_node_state(node, N_MEMORY) { > >=20 >=20> - if (!node_state(node, N_CPU)) > >=20 >=20> - /* > >=20 >=20> - * Defer memory tier initialization on > >=20 >=20> - * CPUless numa nodes. These will be initialized > >=20 >=20> - * after firmware and devices are initialized. > >=20 >=20> - */ > >=20 >=20> - continue; > >=20 >=20> - > >=20 >=20> - memtier =3D set_node_memory_tier(node); > >=20 >=20> - if (IS_ERR(memtier)) > >=20 >=20> - /* > >=20 >=20> - * Continue with memtiers we are able to setup > >=20 >=20> - */ > >=20 >=20> - break; > >=20 >=20> - } > >=20 >=20> - establish_demotion_targets(); > >=20 >=20> - mutex_unlock(&memory_tier_lock); > >=20 >=20> + /* Record nodes with memory and CPU to set default DRAM performa= nce. */ > >=20 >=20> + nodes_and(default_dram_nodes, node_states[N_MEMORY], > >=20 >=20> + node_states[N_CPU]); > >=20 >=20>=20=20 >=20>=20 >=20> hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_= PRI); > >=20 >=20> return 0; > >=20 >=20 > -- >=20 >=20Best Regards, >=20 >=20Huang, Ying > -- Best Regards, Ho-Ren (Jack) Chuang