June 24, 2024 at 1:27 AM, "Huang, Ying" <ying.hu...@intel.com> wrote:
Hi Huang, Ying, Thanks for your feedback. Replies inlined. > > Hi, Jack, > > Thanks for patch! > > "Ho-Ren (Jack) Chuang" <horen.chu...@linux.dev> writes: > > > > > If we simply move the set_node_memory_tier() from memory_tier_init() to > > > > late_initcall(), it will result in HMAT not registering the > > > > mt_adistance_algorithm callback function, because set_node_memory_tier() > > > > is not performed during the memory tiering initialization phase, > > > > leading to a lack of correct default_dram information. > > > > Therefore, we introduced a nodemask to pass the information of the > > > > default DRAM nodes. The reason for not choosing to reuse > > > > default_dram_type->nodes is that it is not clean enough. So in the end, > > > > we use a __initdata variable, which is a variable that is released once > > > > initialization is complete, including both CPU and memory nodes for HMAT > > > > to iterate through. > > > > Besides, since default_dram_type may be checked/used during the > > > > initialization process of HMAT and drivers, it is better to keep the > > > > allocation of default_dram_type in memory_tier_init(). > > > > Signed-off-by: Ho-Ren (Jack) Chuang <horenchu...@bytedance.com> > > > > Suggested-by: Jonathan Cameron <jonathan.came...@huawei.com> > Thank you for your help with the input. Will add it in the v2. > > > > --- > > > > Hi all, > > > > The current memory tier initialization process is distributed across two > > > > different functions, memory_tier_init() and memory_tier_late_init(). This > > > > design is hard to maintain. Thus, this patch is proposed to reduce the > > > > possible code paths by consolidating different initialization patches into > > one. > > > > The earlier discussion with Jonathan and Ying is listed here: > > > > https://lore.kernel.org/lkml/20240405150244.00004...@huawei.com/ > > > > If we want to put these two initializations together, they must be placed > > > > together in the later function. Because only at that time, the HMAT > > information > > > > will be ready, adist between nodes can be calculated, and memory tiering > > can be > > > > established based on the adist. So we position the initialization at > > > > memory_tier_init() to the memory_tier_late_init() call. > > > > Moreover, it's natural to keep memory_tier initialization in drivers at > > > > device_initcall() level. > > > > This patchset is based on commits cf93be18fa1b and a72a30af550c: > > > > [0/2] > > https://lkml.kernel.org/r/20240405000707.2670063-1-horenchu...@bytedance.com > > > > [1/2] > > https://lkml.kernel.org/r/20240405000707.2670063-2-horenchu...@bytedance.com > > > > [1/2] > > https://lkml.kernel.org/r/20240405000707.2670063-3-horenchu...@bytedance.com > > > > It appears that you should switch the parts before and after "---". > > This is the real patch description, as pointed out by Andrew too. > Thank you for the suggestion. I plan to write the real patch description in the cover letter in the next version to avoid any misunderstanding. > > > > Thanks, > > > > Ho-Ren (Jack) Chuang > > > > drivers/acpi/numa/hmat.c | 4 ++- > > > > include/linux/memory-tiers.h | 6 ++++ > > > > mm/memory-tiers.c | 70 ++++++++++++++++++------------------ > > > > 3 files changed, 44 insertions(+), 36 deletions(-) > > > > diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > > > > index 2c8ccc91ebe6..31a77a3324a8 100644 > > > > --- a/drivers/acpi/numa/hmat.c > > > > +++ b/drivers/acpi/numa/hmat.c > > > > @@ -939,11 +939,13 @@ static int hmat_set_default_dram_perf(void) > > > > int nid, pxm; > > > > struct memory_target *target; > > > > struct access_coordinate *attrs; > > > > + nodemask_t default_dram_nodes; > > > > > > > > if (!default_dram_type) > > > > return -EIO; > > > > > > > > - for_each_node_mask(nid, default_dram_type->nodes) { > > > > + default_dram_nodes = mt_get_default_dram_nodemask(); > > > > + for_each_node_mask(nid, default_dram_nodes) { > > > > We don't need 'default_dram_type' in the function actually. It appears > > that we can hide it in memory-tiers.c now? > Do you mean to remove the "if (!default_dram_type) return -EIO;" here? If so, I agree, it's not used anymore here. > > > > pxm = node_to_pxm(nid); > > > > target = find_mem_target(pxm); > > > > if (!target) > > > > diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h > > > > index 0d70788558f4..1567db7bd40e 100644 > > > > --- a/include/linux/memory-tiers.h > > > > +++ b/include/linux/memory-tiers.h > > > > @@ -51,6 +51,7 @@ int mt_perf_to_adistance(struct access_coordinate *perf, > > int *adist); > > > > struct memory_dev_type *mt_find_alloc_memory_type(int adist, > > > > struct list_head *memory_types); > > > > void mt_put_memory_types(struct list_head *memory_types); > > > > +nodemask_t mt_get_default_dram_nodemask(void); > > > > #ifdef CONFIG_MIGRATION > > > > int next_demotion_node(int node); > > > > void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); > > > > @@ -149,5 +150,10 @@ static inline struct memory_dev_type > > *mt_find_alloc_memory_type(int adist, > > > > static inline void mt_put_memory_types(struct list_head *memory_types) > > > > { > > > > } > > > > + > > > > +static inline nodemask_t mt_get_default_dram_nodemask(void) > > > > +{ > > > > + return NODE_MASK_NONE; > > > > +} > > > > #endif /* CONFIG_NUMA */ > > > > #endif /* _LINUX_MEMORY_TIERS_H */ > > > > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > > > > index 6632102bd5c9..7d4b7f53dd8f 100644 > > > > --- a/mm/memory-tiers.c > > > > +++ b/mm/memory-tiers.c > > > > @@ -43,6 +43,7 @@ static LIST_HEAD(memory_tiers); > > > > static LIST_HEAD(default_memory_types); > > > > static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; > > > > struct memory_dev_type *default_dram_type; > > > > +static nodemask_t default_dram_nodes __initdata = NODE_MASK_NONE; > > > > > > > > static const struct bus_type memory_tier_subsys = { > > > > .name = "memory_tiering", > > > > @@ -125,6 +126,11 @@ static inline struct memory_tier > > *to_memory_tier(struct device *device) > > > > return container_of(device, struct memory_tier, dev); > > > > } > > > > > > > > +nodemask_t __init mt_get_default_dram_nodemask(void) > > > > +{ > > > > + return default_dram_nodes; > > > > +} > > > > + > > > > Why not just expose 'default_dram_nodes'? > I was thinking encapsulating it should be more systematic/structural. Do you think exposing it is better? > > > > static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier > > *memtier) > > > > { > > > > nodemask_t nodes = NODE_MASK_NONE; > > > > @@ -671,27 +677,38 @@ EXPORT_SYMBOL_GPL(mt_put_memory_types); > > > > > > > > /* > > > > * This is invoked via `late_initcall()` to initialize memory tiers for > > > > - * CPU-less memory nodes after driver initialization, which is > > > > - * expected to provide `adistance` algorithms. > > > > + * memory nodes, both with and without CPUs. After the initialization of > > > > + * firmware and devices, adistance algorithms are expected to be provided. > > > > */ > > > > static int __init memory_tier_late_init(void) > > > > { > > > > int nid; > > > > + struct memory_tier *memtier; > > > > > > > > guard(mutex)(&memory_tier_lock); > > > > + /* > > > > + * Look at all the existing and uninitialized N_MEMORY nodes and > > > > + * add them to default memory tier or to a tier if we already have > > > > + * memory types assigned. > > > > + */ > > > > for_each_node_state(nid, N_MEMORY) { > > > > During the function run, the node may change between N_MEMORY and > > !N_MEMORY in theory. So, it appears necessary to get/put_online_mems() > > in the function? > Thanks for the catch. I will add get/put_online_mems(). > > > > - /* > > > > - * Some device drivers may have initialized memory tiers > > > > - * between `memory_tier_init()` and `memory_tier_late_init()`, > > > > - * potentially bringing online memory nodes and > > > > - * configuring memory tiers. Exclude them here. > > > > - */ > > > > - if (node_memory_types[nid].memtype) > > > > - continue; > > > > + if (!node_state(nid, N_CPU)) > > > > Why? I think that we should "continue" here even if node_state(nid, > > N_CPU). > Do you mean no matter node_state(nid, N_CPU) or !node_state(nid, N_CPU), as long as if (node_memory_types[nid].memtype) is true, we should "continue"? I think you are right, at this moment, we only care if the node_memory_types[nid].memtype is set or not. If not, we should set it here. If yes, we should continue. If my understanding is correct, I will fix it in the v2. > > > > + /* > > > > + * Some device drivers may have initialized > > > > + * memory tiers, potentially bringing memory nodes > > > > + * online and configuring memory tiers. > > > > + * Exclude them here. > > > > + */ > > > > + if (node_memory_types[nid].memtype) > > > > + continue; > > > > > > > > - set_node_memory_tier(nid); > > > > + memtier = set_node_memory_tier(nid); > > > > + if (IS_ERR(memtier)) > > > > + /* > > > > + * Continue with memtiers we are able to setup. > > > > + */ > > > > + break; > > > > } > > > > - > > > > establish_demotion_targets(); > > > > > > > > return 0; > > > > @@ -876,7 +893,6 @@ static int __meminit memtier_hotplug_callback(struct > > notifier_block *self, > > > > static int __init memory_tier_init(void) > > > > { > > > > int ret, node; > > > > - struct memory_tier *memtier; > > > > > > > > ret = subsys_virtual_register(&memory_tier_subsys, NULL); > > > > if (ret) > > > > @@ -887,7 +903,8 @@ static int __init memory_tier_init(void) > > > > GFP_KERNEL); > > > > WARN_ON(!node_demotion); > > > > #endif > > > > - mutex_lock(&memory_tier_lock); > > > > + > > > > + guard(mutex)(&memory_tier_lock); > > > > /* > > > > * For now we can have 4 faster memory tiers with smaller adistance > > > > * than default DRAM tier. > > > > @@ -898,28 +915,11 @@ static int __init memory_tier_init(void) > > > > panic("%s() failed to allocate default DRAM tier\n", __func__); > > > > > > > > /* > > > > - * Look at all the existing N_MEMORY nodes and add them to > > > > - * default memory tier or to a tier if we already have memory > > > > - * types assigned. > > > > + * Record nodes with memory and CPU to set default DRAM performance. > > > > */ > > > > For one line comments, we can use > > /* Record nodes with memory and CPU to set default DRAM performance. */ > Thank you for the guidance. Will fix in the v2. > > > > - for_each_node_state(node, N_MEMORY) { > > > > - if (!node_state(node, N_CPU)) > > > > - /* > > > > - * Defer memory tier initialization on > > > > - * CPUless numa nodes. These will be initialized > > > > - * after firmware and devices are initialized. > > > > - */ > > > > - continue; > > > > - > > > > - memtier = set_node_memory_tier(node); > > > > - if (IS_ERR(memtier)) > > > > - /* > > > > - * Continue with memtiers we are able to setup > > > > - */ > > > > - break; > > > > - } > > > > - establish_demotion_targets(); > > > > - mutex_unlock(&memory_tier_lock); > > > > + for_each_node_state(node, N_MEMORY) > > > > + if (node_state(node, N_CPU)) > > > > + node_set(node, default_dram_nodes); > > > > Why not use > > nodes_andnot(default_dram_nodes, node_states[N_MEMORY], node_states[N_CPU]); > Instead of using nodes_andnot(), should nodes_and() be correct? because we wanna record the nodes that are both N_MEMORY and N_CPU. > > > > hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI); > > > > return 0; > > > > -- > > Best Regards, > > Huang, Ying >
