kernel/linux.git/mm/swap.h, branch v6.7

mempolicy: alloc_pages_mpol() for NUMA policy without vma

2023-10-25T23:47:16+00:00

Shrink shmem's stack usage by eliminating the pseudo-vma from its folio allocation. alloc_pages_mpol(gfp, order, pol, ilx, nid) becomes the principal actor for passing mempolicy choice down to __alloc_pages(), rather than vma_alloc_folio(gfp, order, vma, addr, hugepage). vma_alloc_folio() and alloc_pages() remain, but as wrappers around alloc_pages_mpol(). alloc_pages_bulk_*() untouched, except to provide the additional args to policy_nodemask(), which subsumes policy_node(). Cleanup throughout, cutting out some unhelpful "helpers". It would all be much simpler without MPOL_INTERLEAVE, but that adds a dynamic to the constant mpol: complicated by v3.6 commit 09c231cb8bfd ("tmpfs: distribute interleave better across nodes"), which added ino bias to the interleave, hidden from mm/mempolicy.c until this commit. Hence "ilx" throughout, the "interleave index". Originally I thought it could be done just with nid, but that's wrong: the nodemask may come from the shared policy layer below a shmem vma, or it may come from the task layer above a shmem vma; and without the final nodemask then nodeid cannot be decided. And how ilx is applied depends also on page order. The interleave index is almost always irrelevant unless MPOL_INTERLEAVE: with one exception in alloc_pages_mpol(), where the NO_INTERLEAVE_INDEX passed down from vma-less alloc_pages() is also used as hint not to use THP-style hugepage allocation - to avoid the overhead of a hugepage arg (though I don't understand why we never just added a GFP bit for THP - if it actually needs a different allocation strategy from other pages of the same order). vma_alloc_folio() still carries its hugepage arg here, but it is not used, and should be removed when agreed. get_vma_policy() no longer allows a NULL vma: over time I believe we've eradicated all the places which used to need it e.g. swapoff and madvise used to pass NULL vma to read_swap_cache_async(), but now know the vma. [hughd@google.com: handle NULL mpol being passed to __read_swap_cache_async()] Link: https://lkml.kernel.org/r/ea419956-4751-0102-21f7-9c93cb957892@google.com Link: https://lkml.kernel.org/r/74e34633-6060-f5e3-aee-7040d43f2e93@google.com Link: https://lkml.kernel.org/r/1738368e-bac0-fd11-ed7f-b87142a939fe@google.com Signed-off-by: Hugh Dickins Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Huang Ying Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Cc: Domenico Cerasuolo Cc: Johannes Weiner Signed-off-by: Andrew Morton

swap: remove remnants of polling from read_swap_cache_async

2023-08-24T23:20:16+00:00

Patch series "Per-VMA lock support for swap and userfaults", v7. When per-VMA locks were introduced in [1] several types of page faults would still fall back to mmap_lock to keep the patchset simple. Among them are swap and userfault pages. The main reason for skipping those cases was the fact that mmap_lock could be dropped while handling these faults and that required additional logic to be implemented. Implement the mechanism to allow per-VMA locks to be dropped for these cases. First, change handle_mm_fault to drop per-VMA locks when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED to be consistent with the way mmap_lock is handled. Then change folio_lock_or_retry to accept vm_fault and return vm_fault_t which simplifies later patches. Finally allow swap and uffd page faults to be handled under per-VMA locks by dropping per-VMA and retrying, the same way it's done under mmap_lock. Naturally, once VMA lock is dropped that VMA should be assumed unstable and can't be used. This patch (of 6): Commit [1] introduced IO polling support duding swapin to reduce swap read latency for block devices that can be polled. However later commit [2] removed polling support. Therefore it seems safe to remove do_poll parameter in read_swap_cache_async and always call swap_readpage with synchronous=false waiting for IO completion in folio_lock_or_retry. [1] commit 23955622ff8d ("swap: add block io poll in swapin path") [2] commit 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio") Link: https://lkml.kernel.org/r/20230630211957.1341547-1-surenb@google.com Link: https://lkml.kernel.org/r/20230630211957.1341547-2-surenb@google.com Signed-off-by: Suren Baghdasaryan Suggested-by: "Huang, Ying" Reviewed-by: "Huang, Ying" Reviewed-by: Christoph Hellwig Cc: Alistair Popple Cc: Al Viro Cc: Christian Brauner Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Hillf Danton Cc: Hugh Dickins Cc: Jan Kara Cc: Johannes Weiner Cc: Josef Bacik Cc: Laurent Dufour Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: Michal Hocko Cc: Michel Lespinasse Cc: Minchan Kim Cc: Pavel Tatashin Cc: Peter Xu Cc: Punit Agrawal Cc: Vlastimil Babka Cc: Yu Zhao Signed-off-by: Andrew Morton

mm: remove the __swap_writepage return value

2023-02-03T06:33:33+00:00

__swap_writepage always returns 0. Link: https://lkml.kernel.org/r/20230125133436.447864-6-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Dan Williams Cc: Dave Jiang Cc: Ira Weiny Cc: Jens Axboe Cc: Keith Busch Cc: Minchan Kim Cc: Sergey Senozhatsky Cc: Vishal Verma Signed-off-by: Andrew Morton

mm: remove the swap_readpage return value

2023-02-03T06:33:33+00:00

swap_readpage always returns 0, and no caller checks the return value. [akpm@linux-foundation.org: fix void-returning swap_readpage() stub, per Keith] Link: https://lkml.kernel.org/r/20230125133436.447864-3-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Dan Williams Cc: Dave Jiang Cc: Ira Weiny Cc: Jens Axboe Cc: Keith Busch Cc: Minchan Kim Cc: Sergey Senozhatsky Cc: Vishal Verma Signed-off-by: Andrew Morton

mm: convert find_get_incore_page() to filemap_get_incore_folio()

2022-11-09T01:37:18+00:00

Return the containing folio instead of the precise page. One of the callers wants the folio and the other can do the folio->page conversion itself. Nets 442 bytes of text size reduction, 478 bytes removed and 36 bytes added. Link: https://lkml.kernel.org/r/20221019183332.2802139-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: remove lookup_swap_cache()

2022-10-03T21:02:51+00:00

All callers have now been converted to swap_cache_get_folio(), so we can remove this wrapper. Link: https://lkml.kernel.org/r/20220902194653.1739778-39-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

swap: add swap_cache_get_folio()

2022-10-03T21:02:48+00:00

Convert lookup_swap_cache() into swap_cache_get_folio() and add a lookup_swap_cache() wrapper around it. [akpm@linux-foundation.org: add CONFIG_SWAP=n stub for swap_cache_get_folio()] Link: https://lkml.kernel.org/r/20220902194653.1739778-20-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm/swap: convert add_to_swap_cache() to take a folio

2022-10-03T21:02:46+00:00

With all callers using folios, we can convert add_to_swap_cache() to take a folio and use it throughout. Link: https://lkml.kernel.org/r/20220902194653.1739778-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm/swap: remove the end_write_func argument to __swap_writepage

2022-09-12T03:25:50+00:00

The argument is always set to end_swap_bio_write, so remove the argument and mark end_swap_bio_write static. Link: https://lkml.kernel.org/r/20220811141741.660214-1-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Seth Jennings Cc: Dan Streetman Cc: Vitaly Wool Signed-off-by: Andrew Morton

mm/khugepaged: try to free transhuge swapcache when possible

2022-07-04T01:08:52+00:00

Transhuge swapcaches won't be freed in __collapse_huge_page_copy(). It's because release_pte_page() is not called for these pages and thus free_page_and_swap_cache can't grab the page lock. These pages won't be freed from swap cache even if we are the only user until next time reclaim. It shouldn't hurt indeed, but we could try to free these pages to save more memory for system. Link: https://lkml.kernel.org/r/20220625092816.4856-8-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Alistair Popple Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: David Howells Cc: Matthew Wilcox (Oracle) Cc: NeilBrown Cc: Peter Xu Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yang Shi Cc: Zach O'Keefe Signed-off-by: Andrew Morton