memblock_est...r_free_pages(9)

💖 memblock_estimated_nr_free_pages(9) 💖

bestie, welcome to the Kernel API Manual page for memblock_estimated_nr_free_pages(9). This is the one where memblock gives you a vibe-check number of free pages, not the final precise count. 🫶

🦋 NAME 🦋

• memblock_estimated_nr_free_pages — return estimated number of free pages from memblock point of view. ✨

🌸 SYNOPSIS 🌸

unsigned long memblock_estimated_nr_free_pages (void );

🍓 ARGUMENTS 🍓

• void — no arguments. literally none. zero. the void is voiding. 🕳️

✨ DESCRIPTION ✨

okay so during bootup, subsystems might need a rough estimate of the number of free pages in the whole system, before precise numbers are available from the buddy. 👀

especially with CONFIG_DEFERRED_STRUCT_PAGE_INIT, the numbers obtained from the buddy might be very imprecise during bootup. so yeah, this is the lowkey “good enough for now” estimate from memblock’s point of view. no cap. 💅

🎀 RETURN 🎀

• An estimated number of free pages from memblock point of view. 🫧

🔥 SEE ALSO 🔥

the whole memblock cinematic universe, no skips. iykyk:

• Kernel file: ./mm/memblock.c
• memblock overview(9)
• __memblock_find_range_bottom_up(9)
• __memblock_find_range_top_down(9)
• memblock_find_in_range_node(9)
• memblock_find_in_range(9)
• memblock_discard(9)
• memblock_double_array(9)
• memblock_merge_regions(9)
• memblock_insert_region(9)
• memblock_add_range(9)
• memblock_add_node(9)
• memblock_add(9)
• memblock_validate_numa_coverage(9)
• memblock_isolate_range(9)
• memblock_free(9)
• memblock_phys_free(9)
• memblock_setclr_flag(9)
• memblock_mark_hotplug(9)
• memblock_clear_hotplug(9)
• memblock_mark_mirror(9)
• memblock_mark_nomap(9)
• memblock_clear_nomap(9)
• memblock_reserved_mark_noinit(9)
• memblock_reserved_mark_kern(9)
• memblock_mark_kho_scratch(9)
• memblock_clear_kho_scratch(9)
• __next_mem_range(9)
• __next_mem_range_rev(9)
• memblock_set_node(9)
• memblock_alloc_range_nid(9)
• memblock_phys_alloc_range(9)
• memblock_phys_alloc_try_nid(9)
• memblock_alloc_internal(9)
• memblock_alloc_exact_nid_raw(9)
• memblock_alloc_try_nid_raw(9)
• memblock_alloc_hugetlb(9)
• memblock_alloc_try_nid(9)
• __memblock_alloc_or_panic(9)
• memblock_is_region_memory(9)
• memblock_is_region_reserved(9)
• memblock_free_all(9)
• reserve_mem_find_by_name(9)
• reserve_mem_release_by_name(9)

mwah 💋 this page’s source/version tag is ./mm, dated October 2026, and the footer page name is memblock_est...r_free_pages(9) — periodt. 🌈