zbud is a memory allocator for storing compressed data pages. It keeps two data objects of arbitrary size on a single page. This simple design provides very deterministic behavior on reclamation, which is one of reasons why zswap selected zbud as a default allocator over zsmalloc. Unlike zsmalloc, however, zbud does not support highmem. This is problomatic especially on 32-bit machines having relatively small lowmem. Compressing anonymous pages from highmem and storing them into lowmem could eat up lowmem spaces. This limitation is due to the fact that zbud manages its internal data structures on zbud_header which is kept in the head of zbud_page. For example, zbud_pages are tracked by several lists and have some status information, which are being referenced at any time by the kernel. Thus, zbud_pages should be allocated on a memory region directly mapped, lowmem. After some digging out, I found that internal data structures of zbud can be kept in the struct page, the same way as zsmalloc does. So, this series moves out all fields in zbud_header to struct page. Though it alters quite a lot, it does not add any functional differences except highmem support. I am afraid that this kind of modification abusing several fields in struct page would be ok. Heesub Shin (9): mm/zbud: tidy up a bit mm/zbud: remove buddied list from zbud_pool mm/zbud: remove lru from zbud_header mm/zbud: remove first|last_chunks from zbud_header mm/zbud: encode zbud handle using struct page mm/zbud: remove list_head for buddied list from zbud_header mm/zbud: drop zbud_header mm/zbud: allow clients to use highmem pages mm/zswap: use highmem pages for compressed pool mm/zbud.c | 244 ++++++++++++++++++++++++++++++------------------------------- mm/zswap.c | 4 +- 2 files changed, 121 insertions(+), 127 deletions(-) -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>