The DEV_DAX_KMEM facility is a generic mechanism to allow device-dax instances, fronting performance-differentiated-memory like pmem, to be added to the System RAM pool. The numa node for that hot-added memory is derived from the device-dax instance's 'target_node' attribute.
Recall that the 'target_node' is the ACPI-PXM-to-node translation for memory when it comes online whereas the 'numa_node' attribute of the device represents the closest online cpu node. Presently useful target_node information from the ACPI SRAT is discarded with the expectation that "Reserved" memory will never be onlined. Now, DEV_DAX_KMEM violates that assumption, there is a need to retain the translation. Move, rather than discard, numa_memblk data to a secondary array that memory_add_physaddr_to_target_node() may consider at a later point in time. Note that memory_add_physaddr_to_nid() is currently only available on CONFIG_MEMORY_HOTPLUG=y platforms whereas the target node information may be useful on CONFIG_MEMORY_HOTPLUG=n builds, hence why it is calling phys_to_target_node() and optionally defined by asm/io.h rather than a memory_add_physaddr_to_target_nid() helper that lives in include/linux/memory_hotplug.h. Cc: Dave Hansen <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: <[email protected]> Cc: Andrew Morton <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Michal Hocko <[email protected]> Reported-by: kbuild test robot <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- arch/x86/mm/numa.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++--- include/linux/numa.h | 8 +++++ mm/mempolicy.c | 5 +++ 3 files changed, 83 insertions(+), 6 deletions(-) diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index 4123100e0eaf..f4f02ac0c465 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -31,6 +31,24 @@ __initdata #endif ; +/* + * Presently, DEV_DAX_KMEM is the only kernel facility that might + * convert Reserved or Soft Reserved memory to System RAM. + */ +#if IS_ENABLED(CONFIG_DEV_DAX_KMEM) +static struct numa_meminfo __numa_reserved_meminfo; + +static struct numa_meminfo *numa_reserved_meminfo(void) +{ + return &__numa_reserved_meminfo; +} +#else +static struct numa_meminfo *numa_reserved_meminfo(void) +{ + return NULL; +} +#endif + static int numa_distance_cnt; static u8 *numa_distance; @@ -168,6 +186,26 @@ void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi) (mi->nr_blks - idx) * sizeof(mi->blk[0])); } +/** + * numa_move_memblk - Move one numa_memblk from one numa_meminfo to another + * @dst: numa_meminfo to move block to + * @idx: Index of memblk to remove + * @src: numa_meminfo to remove memblk from + * + * If @dst is non-NULL add it at the @dst->nr_blks index and increment + * @dst->nr_blks, then remove it from @src. + */ +static void __init numa_move_memblk(struct numa_meminfo *dst, int idx, + struct numa_meminfo *src) +{ + if (dst) { + memcpy(&dst->blk[dst->nr_blks], &src->blk[idx], + sizeof(struct numa_memblk)); + dst->nr_blks++; + } + numa_remove_memblk_from(idx, src); +} + /** * numa_add_memblk - Add one numa_memblk to numa_meminfo * @nid: NUMA node ID of the new memblk @@ -245,7 +283,7 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi) if (bi->start >= bi->end || !memblock_overlaps_region(&memblock.memory, bi->start, bi->end - bi->start)) - numa_remove_memblk_from(i--, mi); + numa_move_memblk(numa_reserved_meminfo(), i--, mi); } /* merge neighboring / overlapping entries */ @@ -881,16 +919,44 @@ EXPORT_SYMBOL(cpumask_of_node); #endif /* !CONFIG_DEBUG_PER_CPU_MAPS */ +static int meminfo_to_nid(struct numa_meminfo *mi, u64 start, int *nid) +{ + int i; + + for (i = 0; mi && i < mi->nr_blks; i++) + if (mi->blk[i].start <= start && mi->blk[i].end > start) { + *nid = mi->blk[i].nid; + break; + } + return i; +} + +int phys_to_target_node(phys_addr_t start) +{ + struct numa_meminfo *mi = &numa_meminfo; + int nid = mi->blk[0].nid; + int i = meminfo_to_nid(mi, start, &nid); + + /* + * Prefer online nodes, but if reserved memory might be + * hot-added continue the search with reserved ranges. + */ + if (i < mi->nr_blks) + return nid; + + mi = numa_reserved_meminfo(); + meminfo_to_nid(mi, start, &nid); + return nid; +} +EXPORT_SYMBOL_GPL(phys_to_target_node); + #ifdef CONFIG_MEMORY_HOTPLUG int memory_add_physaddr_to_nid(u64 start) { struct numa_meminfo *mi = &numa_meminfo; int nid = mi->blk[0].nid; - int i; - for (i = 0; i < mi->nr_blks; i++) - if (mi->blk[i].start <= start && mi->blk[i].end > start) - nid = mi->blk[i].nid; + meminfo_to_nid(mi, start, &nid); return nid; } EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid); diff --git a/include/linux/numa.h b/include/linux/numa.h index 20f4e44b186c..941790a0765b 100644 --- a/include/linux/numa.h +++ b/include/linux/numa.h @@ -1,7 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_NUMA_H #define _LINUX_NUMA_H - +#include <linux/types.h> #ifdef CONFIG_NODES_SHIFT #define NODES_SHIFT CONFIG_NODES_SHIFT @@ -15,11 +15,17 @@ #ifdef CONFIG_NUMA int numa_map_to_online_node(int node); +int phys_to_target_node(phys_addr_t addr); #else static inline int numa_map_to_online_node(int node) { return NUMA_NO_NODE; } + +static inline int phys_to_target_node(phys_addr_t addr) +{ + return NUMA_NO_NODE; +} #endif #endif /* _LINUX_NUMA_H */ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d618121bcc17..0db8b446e23e 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2996,3 +2996,8 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) p += scnprintf(p, buffer + maxlen - p, ":%*pbl", nodemask_pr_args(&nodes)); } + +__weak int phys_to_target_node(phys_addr_t addr) +{ + return NUMA_NO_NODE; +} _______________________________________________ Linux-nvdimm mailing list -- [email protected] To unsubscribe send an email to [email protected]
