From: Michal Hocko mhocko@suse.com
mainline inclusion from mainline-v5.18-rc1 commit 09f49dca570a917a8c6bccd7e8c61f5141534e3a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8EQ3K
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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We have had several reports [1][2][3] that page allocator blows up when an allocation from a possible node is requested. The underlying reason is that NODE_DATA for the specific node is not allocated.
NUMA specific initialization is arch specific and it can vary a lot. E.g. x86 tries to initialize all nodes that have some cpu affinity (see init_cpu_to_node) but this can be insufficient because the node might be cpuless for example.
One way to address this problem would be to check for !node_online nodes when trying to get a zonelist and silently fall back to another node. That is unfortunately adding a branch into allocator hot path and it doesn't handle any other potential NODE_DATA users.
This patch takes a different approach (following a lead of [3]) and it pre allocates pgdat for all possible nodes in an arch indipendent code - free_area_init. All uninitialized nodes are treated as memoryless nodes. node_state of the node is not changed because that would lead to other side effects - e.g. sysfs representation of such a node and from past discussions [4] it is known that some tools might have problems digesting that.
Newly allocated pgdat only gets a minimal initialization and the rest of the work is expected to be done by the memory hotplug - hotadd_new_pgdat (renamed to hotadd_init_pgdat).
generic_alloc_nodedata is changed to use the memblock allocator because neither page nor slab allocators are available at the stage when all pgdats are allocated. Hotplug doesn't allocate pgdat anymore so we can use the early boot allocator. The only arch specific implementation is ia64 and that is changed to use the early allocator as well.
[1] http://lkml.kernel.org/r/20211101201312.11589-1-amakhalov@vmware.com [2] http://lkml.kernel.org/r/20211207224013.880775-1-npache@redhat.com [3] http://lkml.kernel.org/r/20190114082416.30939-1-mhocko@kernel.org [4] http://lkml.kernel.org/r/20200428093836.27190-1-srikar@linux.vnet.ibm.com
[akpm@linux-foundation.org: replace comment, per Mike]
Link: https://lkml.kernel.org/r/Yfe7RBeLCijnWBON@dhcp22.suse.cz Reported-by: Alexey Makhalov amakhalov@vmware.com Tested-by: Alexey Makhalov amakhalov@vmware.com Reported-by: Nico Pache npache@redhat.com Acked-by: Rafael Aquini raquini@redhat.com Tested-by: Rafael Aquini raquini@redhat.com Acked-by: David Hildenbrand david@redhat.com Reviewed-by: Oscar Salvador osalvador@suse.de Acked-by: Mike Rapoport rppt@linux.ibm.com Signed-off-by: Michal Hocko mhocko@suse.com Cc: Christoph Lameter cl@linux.com Cc: Dennis Zhou dennis@kernel.org Cc: Eric Dumazet eric.dumazet@gmail.com Cc: Tejun Heo tj@kernel.org Cc: Wei Yang richard.weiyang@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
Conflicts: mm/internal.h mm/page_alloc.c Signed-off-by: Ma Wupeng mawupeng1@huawei.com --- arch/ia64/mm/discontig.c | 4 ++-- include/linux/memory_hotplug.h | 2 +- mm/internal.h | 2 ++ mm/memory_hotplug.c | 21 ++++++++---------- mm/page_alloc.c | 40 ++++++++++++++++++++++++++++++---- 5 files changed, 50 insertions(+), 19 deletions(-)
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c index 1975f599d914..d72ad280c932 100644 --- a/arch/ia64/mm/discontig.c +++ b/arch/ia64/mm/discontig.c @@ -630,11 +630,11 @@ void __init paging_init(void) zero_page_memmap_ptr = virt_to_page(ia64_imva(empty_zero_page)); }
-pg_data_t *arch_alloc_nodedata(int nid) +pg_data_t * __init arch_alloc_nodedata(int nid) { unsigned long size = compute_pernodesize(nid);
- return kzalloc(size, GFP_KERNEL); + return memblock_alloc(size, SMP_CACHE_BYTES); }
void arch_free_nodedata(pg_data_t *pgdat) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index a026220742cc..aaacbd41940d 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -43,7 +43,7 @@ extern void arch_refresh_nodedata(int nid, pg_data_t *pgdat); */ #define generic_alloc_nodedata(nid) \ ({ \ - kzalloc(sizeof(pg_data_t), GFP_KERNEL); \ + memblock_alloc(sizeof(*pgdat), SMP_CACHE_BYTES); \ }) /* * This definition is just for error path in node hotadd. diff --git a/mm/internal.h b/mm/internal.h index 13f78c5cd961..a9fc47f3677f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -671,4 +671,6 @@ struct migration_target_control { gfp_t gfp_mask; };
+DECLARE_PER_CPU(struct per_cpu_nodestat, boot_nodestats); + #endif /* __MM_INTERNAL_H */ diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 654ab82447c8..12698242b03d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -764,19 +764,21 @@ static void reset_node_present_pages(pg_data_t *pgdat) }
/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ -static pg_data_t __ref *hotadd_new_pgdat(int nid) +static pg_data_t __ref *hotadd_init_pgdat(int nid) { struct pglist_data *pgdat;
pgdat = NODE_DATA(nid); - if (!pgdat) { - pgdat = arch_alloc_nodedata(nid); - if (!pgdat) - return NULL;
+ /* + * NODE_DATA is preallocated (free_area_init) but its internal + * state is not allocated completely. Add missing pieces. + * Completely offline nodes stay around and they just need + * reintialization. + */ + if (pgdat->per_cpu_nodestats == &boot_nodestats) { pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); - arch_refresh_nodedata(nid, pgdat); } else { int cpu; /* @@ -795,8 +797,6 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid) } }
- /* we can use NODE_DATA(nid) from here */ - pgdat->node_id = nid; pgdat->node_start_pfn = 0;
/* init node's zones as empty zones, we don't have any present pages.*/ @@ -848,7 +848,7 @@ static int __try_online_node(int nid, bool set_node_online) if (node_online(nid)) return 0;
- pgdat = hotadd_new_pgdat(nid); + pgdat = hotadd_init_pgdat(nid); if (!pgdat) { pr_err("Cannot online node %d due to NULL pgdat\n", nid); ret = -ENOMEM; @@ -978,9 +978,6 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
return ret; error: - /* rollback pgdat allocation and others */ - if (new_node) - rollback_node_hotadd(nid); if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) memblock_remove(start, size); mem_hotplug_done(); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b511a3c17769..b29a71546ba4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6393,7 +6393,7 @@ static void pageset_init(struct per_cpu_pageset *p); #define BOOT_PAGESET_HIGH 0 #define BOOT_PAGESET_BATCH 1 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset); -static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats); +DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
static void __build_all_zonelists(void *data) { @@ -6414,7 +6414,11 @@ static void __build_all_zonelists(void *data) if (self && !node_online(self->node_id)) { build_zonelists(self); } else { - for_each_online_node(nid) { + /* + * All possible nodes have pgdat preallocated + * in free_area_init + */ + for_each_node(nid) { pg_data_t *pgdat = NODE_DATA(nid);
build_zonelists(pgdat); @@ -8046,8 +8050,36 @@ void __init free_area_init(unsigned long *max_zone_pfn) /* Initialise every node */ mminit_verify_pageflags_layout(); setup_nr_node_ids(); - for_each_online_node(nid) { - pg_data_t *pgdat = NODE_DATA(nid); + for_each_node(nid) { + pg_data_t *pgdat; + + if (!node_online(nid)) { + pr_info("Initializing node %d as memoryless\n", nid); + + /* Allocator not initialized yet */ + pgdat = arch_alloc_nodedata(nid); + if (!pgdat) { + pr_err("Cannot allocate %zuB for node %d.\n", + sizeof(*pgdat), nid); + continue; + } + arch_refresh_nodedata(nid, pgdat); + free_area_init_memoryless_node(nid); + + /* + * We do not want to confuse userspace by sysfs + * files/directories for node without any memory + * attached to it, so this node is not marked as + * N_MEMORY and not marked online so that no sysfs + * hierarchy will be created via register_one_node for + * it. The pgdat will get fully initialized by + * hotadd_init_pgdat() when memory is hotplugged into + * this node. + */ + continue; + } + + pgdat = NODE_DATA(nid); free_area_init_node(nid);
/* Any memory on that node */