restore_highmem(9)

✨ restore_highmem(9) ✨

okay bestie, so this one's from the Kernel API Manual and it's literally called restore_highmem — yes, that's restore_highmem(9), section 9, we're in kernel-land now 💅

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🌸 NAME 🌸

restore_highmem — put highmem image pages into their original locations 🎀

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🦋 SYNOPSIS 🦋

int restore_highmem (void );

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💜 ARGUMENTS 💜

• void — no arguments, bestie. none. zero. the void is voiding 🫶

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🔥 DESCRIPTION 🔥

okay so here's the vibe: for each highmem page that was in use before hibernation and is included in the image, and also has been allocated by the "restore" kernel — this function swaps its current contents with the previous ones (that's the "before hibernation" ones, iykyk) 💖

and like, if the restore eventually fails? no biggie, not the end of the world — you can just call this function once again and restore the highmem state as seen by the restore kernel. iconic recovery behaviour, honestly 👑

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🌈 SEE ALSO 🌈

it's giving ✨ extended universe ✨ — this thing lives in the kernel file ./kernel/power/snapshot.c, and it's friends with literally everyone:

• get_image_page(9)
• free_image_page(9)
• alloc_rtree_node(9)
• free_mem_extents(9)
• create_mem_extents(9)
• memory_bm_next_pfn(9)
• mark_nosave_pages(9)
• create_basic_memory_bitmaps(9)
• free_basic_memory_bitmaps(9)
• snapshot_additional_pages(9)
• count_free_highmem_pages(9)
• count_highmem_pages(9)
• count_data_pages(9)
• swsusp_free(9)
• preallocate_image_pages(9)
• free_unnecessary_pages(9)
• minimum_image_size(9)
• hibernate_preallocate_memory(9)
• pack_pfns(9)
• snapshot_read_next(9)
• unpack_orig_pfns(9)
• count_highmem_image_pages(9)
• prepare_highmem_image(9)
• copy_last_highmem_page(9)
• prepare_image(9)
• snapshot_write_next(9)

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💀 real talk though: read the DESCRIPTION again before you go swapping page contents around, because this is literally memory state from before hibernation. slay responsibly 🫶

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and that's the whole page, bestie — brought to you by the good people at ./kernel/power, dated October 2026 ✨🎀 go forth and restore those highmem pages 💖🦋