ddc1a5cbc0
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 <hughd@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun heo <tj@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Domenico Cerasuolo <mimmocerasuolo@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
149 lines
3.9 KiB
C
149 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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struct mempolicy;
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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 mempolicy *mpol, pgoff_t ilx,
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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 mempolicy *mpol, pgoff_t ilx);
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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 mempolicy *mpol, pgoff_t ilx)
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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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