mm, swap: use page-cluster as max window of VMA based swap readahead

[sfrench/cifs-2.6.git] / mm / swap_state.c

diff --git a/mm/swap_state.c b/mm/swap_state.c
index ed91091d1e68801daa22bd9e2d2a7833233adcfc..05b6803f0cce205ca58410b6932c5af22a6dd7cb 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -39,10 +39,6 @@ struct address_space *swapper_spaces[MAX_SWAPFILES];
 static unsigned int nr_swapper_spaces[MAX_SWAPFILES];
 bool swap_vma_readahead = true;
 
-#define SWAP_RA_MAX_ORDER_DEFAULT      3
-
-static int swap_ra_max_order = SWAP_RA_MAX_ORDER_DEFAULT;
-
 #define SWAP_RA_WIN_SHIFT      (PAGE_SHIFT / 2)
 #define SWAP_RA_HITS_MASK      ((1UL << SWAP_RA_WIN_SHIFT) - 1)
 #define SWAP_RA_HITS_MAX       SWAP_RA_HITS_MASK
@@ -664,6 +660,13 @@ struct page *swap_readahead_detect(struct vm_fault *vmf,
        pte_t *tpte;
 #endif
 
+       max_win = 1 << min_t(unsigned int, READ_ONCE(page_cluster),
+                            SWAP_RA_ORDER_CEILING);
+       if (max_win == 1) {
+               swap_ra->win = 1;
+               return NULL;
+       }
+
        faddr = vmf->address;
        entry = pte_to_swp_entry(vmf->orig_pte);
        if ((unlikely(non_swap_entry(entry))))
@@ -672,12 +675,6 @@ struct page *swap_readahead_detect(struct vm_fault *vmf,
        if (page)
                return page;
 
-       max_win = 1 << READ_ONCE(swap_ra_max_order);
-       if (max_win == 1) {
-               swap_ra->win = 1;
-               return NULL;
-       }
-
        fpfn = PFN_DOWN(faddr);
        swap_ra_info = GET_SWAP_RA_VAL(vma);
        pfn = PFN_DOWN(SWAP_RA_ADDR(swap_ra_info));
@@ -786,32 +783,8 @@ static struct kobj_attribute vma_ra_enabled_attr =
        __ATTR(vma_ra_enabled, 0644, vma_ra_enabled_show,
               vma_ra_enabled_store);
 
-static ssize_t vma_ra_max_order_show(struct kobject *kobj,
-                                    struct kobj_attribute *attr, char *buf)
-{
-       return sprintf(buf, "%d\n", swap_ra_max_order);
-}
-static ssize_t vma_ra_max_order_store(struct kobject *kobj,
-                                     struct kobj_attribute *attr,
-                                     const char *buf, size_t count)
-{
-       int err, v;
-
-       err = kstrtoint(buf, 10, &v);
-       if (err || v > SWAP_RA_ORDER_CEILING || v <= 0)
-               return -EINVAL;
-
-       swap_ra_max_order = v;
-
-       return count;
-}
-static struct kobj_attribute vma_ra_max_order_attr =
-       __ATTR(vma_ra_max_order, 0644, vma_ra_max_order_show,
-              vma_ra_max_order_store);
-
 static struct attribute *swap_attrs[] = {
        &vma_ra_enabled_attr.attr,
-       &vma_ra_max_order_attr.attr,
        NULL,
 };