"Ho-Ren Chuang" <horen.chuang@xxxxxxxxx> writes: > June 24, 2024 at 1:27 AM, "Huang, Ying" <ying.huang@xxxxxxxxx> wrote: > > Hi Huang, Ying, > > Thanks for your feedback. Replies inlined. > >> >> 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> >> > > 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/20240405150244.00004b49@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. >> > > 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. Yes. >> > >> > 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? It doesn't help much to encapsulate with one line function. So, IMO, it's better just to expose it. >> > >> > 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. Yes. That's my opinion too. >> > >> > + /* >> > >> > + * 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. Oh, Yes, you are right. >> > >> > hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI); >> > >> > return 0; >> > >> -- Best Regards, Huang, Ying
