Hi, Jack, Thanks for patch! "Ho-Ren (Jack) Chuang" <horen.chuang@xxxxxxxxx> 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 <horenchuang@xxxxxxxxxxxxx> Suggested-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > --- > 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/20240405150244.00004b49@xxxxxxxxxx/ > > 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-horenchuang@xxxxxxxxxxxxx > [1/2] https://lkml.kernel.org/r/20240405000707.2670063-2-horenchuang@xxxxxxxxxxxxx > [1/2] https://lkml.kernel.org/r/20240405000707.2670063-3-horenchuang@xxxxxxxxxxxxx It appears that you should switch the parts before and after "---". This is the real patch description, as pointed out by Andrew too. > 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? > 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'? > 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? > - /* > - * 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). > + /* > + * 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. */ > - 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]); > hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI); > return 0; -- Best Regards, Huang, Ying
