From: Minchan Kim <minc...@kernel.org> This patch makes do_swap_page() not need to be aware of two different swap readahead algorithms. Just unify cluster-based and vma-based readahead function call.
Link: http://lkml.kernel.org/r/1509520520-32367-3-git-send-email-minc...@kernel.org Signed-off-by: Minchan Kim <minc...@kernel.org> Cc: Hugh Dickins <hu...@google.com> Cc: Huang Ying <ying.hu...@intel.com> Signed-off-by: Minchan Kim <minc...@kernel.org> --- include/linux/swap.h | 27 ++++++++----------------- mm/memory.c | 11 ++++------ mm/shmem.c | 5 ++++- mm/swap_state.c | 48 ++++++++++++++++++++++++++++++++++---------- 4 files changed, 53 insertions(+), 38 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index fa92177d863e..2417d288e016 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -400,7 +400,6 @@ int generic_swapfile_activate(struct swap_info_struct *, struct file *, #define SWAP_ADDRESS_SPACE_SHIFT 14 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) extern struct address_space *swapper_spaces[]; -extern bool swap_vma_readahead; #define swap_address_space(entry) \ (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ >> SWAP_ADDRESS_SPACE_SHIFT]) @@ -422,10 +421,10 @@ extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, struct vm_area_struct *vma, unsigned long addr, bool *new_page_allocated); -extern struct page *swapin_readahead(swp_entry_t, gfp_t, - struct vm_area_struct *vma, unsigned long addr); -extern struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask, - struct vm_fault *vmf); +extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, + struct vm_fault *vmf); +extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, + struct vm_fault *vmf); /* linux/mm/swapfile.c */ extern atomic_long_t nr_swap_pages; @@ -433,11 +432,6 @@ extern long total_swap_pages; extern atomic_t nr_rotate_swap; extern bool has_usable_swap(void); -static inline bool swap_use_vma_readahead(void) -{ - return READ_ONCE(swap_vma_readahead) && !atomic_read(&nr_rotate_swap); -} - /* Swap 50% full? Release swapcache more aggressively.. */ static inline bool vm_swap_full(void) { @@ -533,19 +527,14 @@ static inline void put_swap_page(struct page *page, swp_entry_t swp) { } -static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, - struct vm_area_struct *vma, unsigned long addr) +static inline struct page *swap_cluster_readahead(swp_entry_t entry, + gfp_t gfp_mask, struct vm_fault *vmf) { return NULL; } -static inline bool swap_use_vma_readahead(void) -{ - return false; -} - -static inline struct page *do_swap_page_readahead(swp_entry_t fentry, - gfp_t gfp_mask, struct vm_fault *vmf) +static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, + struct vm_fault *vmf) { return NULL; } diff --git a/mm/memory.c b/mm/memory.c index 5b6e29d927c8..394078c97a98 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2927,7 +2927,8 @@ int do_swap_page(struct vm_fault *vmf) if (si->flags & SWP_SYNCHRONOUS_IO && __swap_count(si, entry) == 1) { /* skip swapcache */ - page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address); + page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, + vmf->address); if (page) { __SetPageLocked(page); __SetPageSwapBacked(page); @@ -2936,12 +2937,8 @@ int do_swap_page(struct vm_fault *vmf) swap_readpage(page, true); } } else { - if (swap_use_vma_readahead()) - page = do_swap_page_readahead(entry, - GFP_HIGHUSER_MOVABLE, vmf); - else - page = swapin_readahead(entry, - GFP_HIGHUSER_MOVABLE, vma, vmf->address); + page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, + vmf); swapcache = page; } diff --git a/mm/shmem.c b/mm/shmem.c index 1907688b75ee..e493c5095b5f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1413,9 +1413,12 @@ static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, { struct vm_area_struct pvma; struct page *page; + struct vm_fault vmf; shmem_pseudo_vma_init(&pvma, info, index); - page = swapin_readahead(swap, gfp, &pvma, 0); + vmf.vma = &pvma; + vmf.address = 0; + page = swap_cluster_readahead(swap, gfp, &vmf); shmem_pseudo_vma_destroy(&pvma); return page; diff --git a/mm/swap_state.c b/mm/swap_state.c index c56cce64b2c3..0b8ae361981f 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -38,7 +38,7 @@ static const struct address_space_operations swap_aops = { struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly; static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly; -bool swap_vma_readahead __read_mostly = true; +bool enable_vma_readahead __read_mostly = true; #define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2) #define SWAP_RA_HITS_MASK ((1UL << SWAP_RA_WIN_SHIFT) - 1) @@ -322,6 +322,11 @@ void free_pages_and_swap_cache(struct page **pages, int nr) release_pages(pagep, nr); } +static inline bool swap_use_vma_readahead(void) +{ + return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap); +} + /* * Lookup a swap entry in the swap cache. A found page will be returned * unlocked and with its refcount incremented - we rely on the kernel @@ -539,11 +544,10 @@ static unsigned long swapin_nr_pages(unsigned long offset) } /** - * swapin_readahead - swap in pages in hope we need them soon + * swap_cluster_readahead - swap in pages in hope we need them soon * @entry: swap entry of this memory * @gfp_mask: memory allocation flags - * @vma: user vma this address belongs to - * @addr: target address for mempolicy + * @vmf: fault information * * Returns the struct page for entry and addr, after queueing swapin. * @@ -555,10 +559,10 @@ static unsigned long swapin_nr_pages(unsigned long offset) * This has been extended to use the NUMA policies from the mm triggering * the readahead. * - * Caller must hold down_read on the vma->vm_mm if vma is not NULL. + * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL. */ -struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, - struct vm_area_struct *vma, unsigned long addr) +struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, + struct vm_fault *vmf) { struct page *page; unsigned long entry_offset = swp_offset(entry); @@ -568,6 +572,8 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, struct swap_info_struct *si = swp_swap_info(entry); struct blk_plug plug; bool do_poll = true, page_allocated; + struct vm_area_struct *vma = vmf->vma; + unsigned long addr = vmf->address; mask = swapin_nr_pages(offset) - 1; if (!mask) @@ -723,7 +729,7 @@ static void swap_ra_info(struct vm_fault *vmf, pte_unmap(orig_pte); } -struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask, +struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, struct vm_fault *vmf) { struct blk_plug plug; @@ -771,20 +777,40 @@ struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask, ra_info.win == 1); } +/** + * swapin_readahead - swap in pages in hope we need them soon + * @entry: swap entry of this memory + * @gfp_mask: memory allocation flags + * @vmf: fault information + * + * Returns the struct page for entry and addr, after queueing swapin. + * + * It's a main entry function for swap readahead. By the configuration, + * it will read ahead blocks by cluster-based(ie, physical disk based) + * or vma-based(ie, virtual address based on faulty address) readahead. + */ +struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, + struct vm_fault *vmf) +{ + return swap_use_vma_readahead() ? + swap_vma_readahead(entry, gfp_mask, vmf) : + swap_cluster_readahead(entry, gfp_mask, vmf); +} + #ifdef CONFIG_SYSFS static ssize_t vma_ra_enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { - return sprintf(buf, "%s\n", swap_vma_readahead ? "true" : "false"); + return sprintf(buf, "%s\n", enable_vma_readahead ? "true" : "false"); } static ssize_t vma_ra_enabled_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { if (!strncmp(buf, "true", 4) || !strncmp(buf, "1", 1)) - swap_vma_readahead = true; + enable_vma_readahead = true; else if (!strncmp(buf, "false", 5) || !strncmp(buf, "0", 1)) - swap_vma_readahead = false; + enable_vma_readahead = false; else return -EINVAL; -- 2.16.1.291.g4437f3f132-goog
