mm: swap: unify cluster-based and vma-based swap readahead

[uclinux-h8/linux.git] / mm / swap_state.c

diff --git a/mm/swap_state.c b/mm/swap_state.c
index db5da2b..b97da97 100644 (file)
--- 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
@@ -544,11 +549,10 @@ 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.
  *
@@ -560,10 +564,10 @@ 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);
@@ -573,6 +577,8 @@ 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)
@@ -727,7 +733,7 @@ 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;
@@ -774,20 +780,40 @@ skip:
                                     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;