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b243dcbf2f
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] commit23955622ff("swap: add block io poll in swapin path") [2] commit9650b453a3("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 <surenb@google.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
148 lines
3.9 KiB
C
148 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _MM_SWAP_H
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#define _MM_SWAP_H
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#ifdef CONFIG_SWAP
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#include <linux/blk_types.h> /* for bio_end_io_t */
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/* linux/mm/page_io.c */
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int sio_pool_init(void);
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struct swap_iocb;
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void swap_readpage(struct page *page, bool do_poll, struct swap_iocb **plug);
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void __swap_read_unplug(struct swap_iocb *plug);
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static inline void swap_read_unplug(struct swap_iocb *plug)
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{
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if (unlikely(plug))
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__swap_read_unplug(plug);
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}
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void swap_write_unplug(struct swap_iocb *sio);
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int swap_writepage(struct page *page, struct writeback_control *wbc);
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void __swap_writepage(struct page *page, struct writeback_control *wbc);
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/* linux/mm/swap_state.c */
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/* One swap address space for each 64M swap space */
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#define SWAP_ADDRESS_SPACE_SHIFT 14
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#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
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extern struct address_space *swapper_spaces[];
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#define swap_address_space(entry) \
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(&swapper_spaces[swp_type(entry)][swp_offset(entry) \
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>> SWAP_ADDRESS_SPACE_SHIFT])
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void show_swap_cache_info(void);
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bool add_to_swap(struct folio *folio);
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void *get_shadow_from_swap_cache(swp_entry_t entry);
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int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
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gfp_t gfp, void **shadowp);
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void __delete_from_swap_cache(struct folio *folio,
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swp_entry_t entry, void *shadow);
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void delete_from_swap_cache(struct folio *folio);
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void clear_shadow_from_swap_cache(int type, unsigned long begin,
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unsigned long end);
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struct folio *swap_cache_get_folio(swp_entry_t entry,
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struct vm_area_struct *vma, unsigned long addr);
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struct folio *filemap_get_incore_folio(struct address_space *mapping,
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pgoff_t index);
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struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
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struct vm_area_struct *vma,
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unsigned long addr,
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struct swap_iocb **plug);
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struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
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struct vm_area_struct *vma,
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unsigned long addr,
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bool *new_page_allocated);
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struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
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struct vm_fault *vmf);
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struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
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struct vm_fault *vmf);
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static inline unsigned int folio_swap_flags(struct folio *folio)
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{
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return page_swap_info(&folio->page)->flags;
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}
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#else /* CONFIG_SWAP */
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struct swap_iocb;
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static inline void swap_readpage(struct page *page, bool do_poll,
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struct swap_iocb **plug)
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{
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}
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static inline void swap_write_unplug(struct swap_iocb *sio)
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{
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}
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static inline struct address_space *swap_address_space(swp_entry_t entry)
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{
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return NULL;
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}
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static inline void show_swap_cache_info(void)
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{
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}
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static inline struct page *swap_cluster_readahead(swp_entry_t entry,
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gfp_t gfp_mask, struct vm_fault *vmf)
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{
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return NULL;
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}
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static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
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struct vm_fault *vmf)
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{
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return NULL;
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}
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static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
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{
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return 0;
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}
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static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
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struct vm_area_struct *vma, unsigned long addr)
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{
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return NULL;
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}
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static inline
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struct folio *filemap_get_incore_folio(struct address_space *mapping,
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pgoff_t index)
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{
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return filemap_get_folio(mapping, index);
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}
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static inline bool add_to_swap(struct folio *folio)
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{
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return false;
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}
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static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
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{
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return NULL;
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}
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static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
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gfp_t gfp_mask, void **shadowp)
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{
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return -1;
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}
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static inline void __delete_from_swap_cache(struct folio *folio,
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swp_entry_t entry, void *shadow)
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{
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}
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static inline void delete_from_swap_cache(struct folio *folio)
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{
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}
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static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
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unsigned long end)
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{
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}
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static inline unsigned int folio_swap_flags(struct folio *folio)
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{
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return 0;
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}
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#endif /* CONFIG_SWAP */
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#endif /* _MM_SWAP_H */
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