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authorMinchan Kim <minchan@kernel.org>2018-04-06 01:23:42 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-06 06:36:25 +0200
commite9e9b7ecee4a139a6fbe2e15ef224ca6b6c47d57 (patch)
tree179430c7efc50a0da618934d117b152258e82353 /mm
parentmm: swap: clean up swap readahead (diff)
downloadlinux-e9e9b7ecee4a139a6fbe2e15ef224ca6b6c47d57.tar.xz
linux-e9e9b7ecee4a139a6fbe2e15ef224ca6b6c47d57.zip
mm: swap: unify cluster-based and vma-based swap readahead
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-minchan@kernel.org Link: http://lkml.kernel.org/r/20180220085249.151400-3-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c11
-rw-r--r--mm/shmem.c5
-rw-r--r--mm/swap_state.c48
3 files changed, 45 insertions, 19 deletions
diff --git a/mm/memory.c b/mm/memory.c
index bc1ccff79538..01f5464e0fd2 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 b85919243399..4424fc0c33aa 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1422,9 +1422,12 @@ 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 db5da2baafb1..b97da97b6846 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
@@ -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;