| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <87tth5h9qc.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date: Thu, 04 Jul 2024 15:55:39 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: "Ho-Ren (Jack) Chuang" <horen.chuang@...ux.dev>
Cc: "Jonathan Cameron" <Jonathan.Cameron@...wei.com>, "Gregory Price"
<gourry.memverge@...il.com>, aneesh.kumar@...ux.ibm.com,
mhocko@...e.com, tj@...nel.org, john@...alactic.com, "Eishan Mirakhur"
<emirakhur@...ron.com>, "Vinicius Tavares Petrucci"
<vtavarespetr@...ron.com>, "Ravis OpenSrc" <Ravis.OpenSrc@...ron.com>,
"Alistair Popple" <apopple@...dia.com>, "Srinivasulu Thanneeru"
<sthanneeru@...ron.com>, "SeongJae Park" <sj@...nel.org>, "Rafael J.
Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>, Andrew Morton
<akpm@...ux-foundation.org>, Dave Jiang <dave.jiang@...el.com>, Dan
Williams <dan.j.williams@...el.com>, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org, "Ho-Ren (Jack)
Chuang" <horenc@...edu>, "Ho-Ren (Jack) Chuang"
<horenchuang@...edance.com>, "Ho-Ren (Jack) Chuang"
<horenchuang@...il.com>, linux-cxl@...r.kernel.org,
qemu-devel@...gnu.org
Subject: Re: [PATCH v3] memory tier: consolidate the initialization of
memory tiers
"Ho-Ren (Jack) Chuang" <horen.chuang@...ux.dev> writes:
> 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@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.
>
> 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.
>
> This patchset is based on commits <cf93be18fa1b> ("memory tier: create
> CPUless memory tiers after obtaining HMAT info") and
> <a72a30af550c> ("memory tier: dax/kmem: introduce an abstract layer for
> finding, allocating, and putting memory types"):
> [0/2] https://lkml.kernel.org/r/20240405000707.2670063-1-horenchuang@bytedance.com
> [1/2] https://lkml.kernel.org/r/20240405000707.2670063-2-horenchuang@bytedance.com
> [1/2] https://lkml.kernel.org/r/20240405000707.2670063-3-horenchuang@bytedance.com
>
> Signed-off-by: Ho-Ren (Jack) Chuang <horenchuang@...edance.com>
> Suggested-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
LGTM, Thanks!
Reviewed-by: "Huang, Ying" <ying.huang@...el.com>
> ---
> - v3:
> * Combine the cover letter and the patch.
> * Remove extern default_dram_type
> * Remove __initdata in a extern variable
> * Roll back coding style, fix comment description
> - v2:
> Thanks to Huang, Ying's and Andrew's comments
> * Add a cover letter
> * Add Suggested-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> * Add get/put_online_mems() protection in memory_tier_late_init()
> * If memtype is set, skip initializing its node
> * Remove redundant code/comments or rewrite code in a cleaner manner
> * https://lore.kernel.org/all/20240628060925.303309-1-horen.chuang@linux.dev/
> - v1:
> * https://lore.kernel.org/all/20240621044833.3953055-1-horen.chuang@linux.dev/
>
> - Open to discussion:
> * Should we use `continue` or `break` if set_node_memory_tier() fails in
> memory_tier_late_init()? I've changed it to `continue` in v3.
> * Compute the default_dram_nodes mask in hmat when needed? Currently,
> it still remains in memory-tiers.c
> * Instead of using guard(mutex)(), use mutex_lock() as it was to make a
> cleaner diff?
>
> Thanks,
> Ho-Ren (Jack) Chuang
>
> drivers/acpi/numa/hmat.c | 5 +---
> include/linux/memory-tiers.h | 2 ++
> mm/memory-tiers.c | 54 ++++++++++++++----------------------
> 3 files changed, 24 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c
> index 2c8ccc91ebe6..a2f9e7a4b479 100644
> --- a/drivers/acpi/numa/hmat.c
> +++ b/drivers/acpi/numa/hmat.c
> @@ -940,10 +940,7 @@ static int hmat_set_default_dram_perf(void)
> struct memory_target *target;
> struct access_coordinate *attrs;
>
> - if (!default_dram_type)
> - return -EIO;
> -
> - for_each_node_mask(nid, default_dram_type->nodes) {
> + for_each_node_mask(nid, default_dram_nodes) {
> 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..0dc0cf2863e2 100644
> --- a/include/linux/memory-tiers.h
> +++ b/include/linux/memory-tiers.h
> @@ -38,6 +38,7 @@ struct access_coordinate;
> #ifdef CONFIG_NUMA
> extern bool numa_demotion_enabled;
> extern struct memory_dev_type *default_dram_type;
> +extern nodemask_t default_dram_nodes;
> struct memory_dev_type *alloc_memory_type(int adistance);
> void put_memory_type(struct memory_dev_type *memtype);
> void init_node_memory_type(int node, struct memory_dev_type *default_type);
> @@ -76,6 +77,7 @@ static inline bool node_is_toptier(int node)
>
> #define numa_demotion_enabled false
> #define default_dram_type NULL
> +#define default_dram_nodes NODE_MASK_NONE
> /*
> * CONFIG_NUMA implementation returns non NULL error.
> */
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index 6632102bd5c9..4775b3a3dabe 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;
> +nodemask_t default_dram_nodes __initdata = NODE_MASK_NONE;
>
> static const struct bus_type memory_tier_subsys = {
> .name = "memory_tiering",
> @@ -671,28 +672,35 @@ 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;
>
> + get_online_mems();
> guard(mutex)(&memory_tier_lock);
> +
> + /* Assign each uninitialized N_MEMORY node to a memory tier. */
> for_each_node_state(nid, N_MEMORY) {
> /*
> - * 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.
> + * 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;
> }
>
> establish_demotion_targets();
> + put_online_mems();
>
> return 0;
> }
> @@ -875,8 +883,7 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self,
>
> static int __init memory_tier_init(void)
> {
> - int ret, node;
> - struct memory_tier *memtier;
> + int ret;
>
> ret = subsys_virtual_register(&memory_tier_subsys, NULL);
> if (ret)
> @@ -887,7 +894,8 @@ 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.
> @@ -897,29 +905,9 @@ static int __init memory_tier_init(void)
> if (IS_ERR(default_dram_type))
> 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.
> - */
> - 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);
> + /* Record nodes with memory and CPU to set default DRAM performance. */
> + nodes_and(default_dram_nodes, node_states[N_MEMORY],
> + node_states[N_CPU]);
>
> hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI);
> return 0;
Powered by blists - more mailing lists