kernel/linux.git/include/linux/page_frag_cache.h, branch v6.19.11

mm: page_frag: reuse existing space for 'size' and 'pfmemalloc'

2024-11-11T18:56:27+00:00

Currently there is one 'struct page_frag' for every 'struct sock' and 'struct task_struct', we are about to replace the 'struct page_frag' with 'struct page_frag_cache' for them. Before begin the replacing, we need to ensure the size of 'struct page_frag_cache' is not bigger than the size of 'struct page_frag', as there may be tens of thousands of 'struct sock' and 'struct task_struct' instances in the system. By or'ing the page order & pfmemalloc with lower bits of 'va' instead of using 'u16' or 'u32' for page size and 'u8' for pfmemalloc, we are able to avoid 3 or 5 bytes space waste. And page address & pfmemalloc & order is unchanged for the same page in the same 'page_frag_cache' instance, it makes sense to fit them together. After this patch, the size of 'struct page_frag_cache' should be the same as the size of 'struct page_frag'. CC: Andrew Morton CC: Linux-MM Signed-off-by: Yunsheng Lin Reviewed-by: Alexander Duyck Link: https://patch.msgid.link/20241028115343.3405838-7-linyunsheng@huawei.com Signed-off-by: Jakub Kicinski

mm: page_frag: avoid caller accessing 'page_frag_cache' directly

2024-11-11T18:56:27+00:00

Use appropriate frag_page API instead of caller accessing 'page_frag_cache' directly. CC: Andrew Morton CC: Linux-MM Signed-off-by: Yunsheng Lin Reviewed-by: Alexander Duyck Acked-by: Chuck Lever Link: https://patch.msgid.link/20241028115343.3405838-5-linyunsheng@huawei.com Signed-off-by: Jakub Kicinski

mm: move the page fragment allocator from page_alloc into its own file

2024-11-11T18:56:26+00:00

Inspired by [1], move the page fragment allocator from page_alloc into its own c file and header file, as we are about to make more change for it to replace another page_frag implementation in sock.c As this patchset is going to replace 'struct page_frag' with 'struct page_frag_cache' in sched.h, including page_frag_cache.h in sched.h has a compiler error caused by interdependence between mm_types.h and mm.h for asm-offsets.c, see [2]. So avoid the compiler error by moving 'struct page_frag_cache' to mm_types_task.h as suggested by Alexander, see [3]. 1. https://lore.kernel.org/all/20230411160902.4134381-3-dhowells@redhat.com/ 2. https://lore.kernel.org/all/15623dac-9358-4597-b3ee-3694a5956920@gmail.com/ 3. https://lore.kernel.org/all/CAKgT0UdH1yD=LSCXFJ=YM_aiA4OomD-2wXykO42bizaWMt_HOA@mail.gmail.com/ CC: David Howells CC: Linux-MM Signed-off-by: Yunsheng Lin Acked-by: Andrew Morton Reviewed-by: Alexander Duyck Link: https://patch.msgid.link/20241028115343.3405838-3-linyunsheng@huawei.com Signed-off-by: Jakub Kicinski