[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/mm/swap_state.c b/ap/os/linux/linux-3.4.x/mm/swap_state.c
new file mode 100644
index 0000000..6c5cf85
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/mm/swap_state.c
@@ -0,0 +1,416 @@
+/*
+ * linux/mm/swap_state.c
+ *
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ * Swap reorganised 29.12.95, Stephen Tweedie
+ *
+ * Rewritten to use page cache, (C) 1998 Stephen Tweedie
+ */
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/kernel_stat.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/backing-dev.h>
+#include <linux/pagevec.h>
+#include <linux/migrate.h>
+#include <linux/page_cgroup.h>
+
+#include <asm/pgtable.h>
+
+/*
+ * swapper_space is a fiction, retained to simplify the path through
+ * vmscan's shrink_page_list.
+ */
+static const struct address_space_operations swap_aops = {
+ .writepage = swap_writepage,
+ .set_page_dirty = __set_page_dirty_no_writeback,
+ .migratepage = migrate_page,
+};
+
+static struct backing_dev_info swap_backing_dev_info = {
+ .name = "swap",
+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
+};
+
+struct address_space swapper_space = {
+ .page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
+ .tree_lock = __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock),
+ .a_ops = &swap_aops,
+ .i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
+ .backing_dev_info = &swap_backing_dev_info,
+};
+
+#define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0)
+
+static struct {
+ unsigned long add_total;
+ unsigned long del_total;
+ unsigned long find_success;
+ unsigned long find_total;
+} swap_cache_info;
+
+void show_swap_cache_info(void)
+{
+ printk("%lu pages in swap cache\n", total_swapcache_pages);
+ printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n",
+ swap_cache_info.add_total, swap_cache_info.del_total,
+ swap_cache_info.find_success, swap_cache_info.find_total);
+ printk("Free swap = %ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
+ printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));
+}
+
+/*
+ * __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
+ * but sets SwapCache flag and private instead of mapping and index.
+ */
+static int __add_to_swap_cache(struct page *page, swp_entry_t entry)
+{
+ int error;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(PageSwapCache(page));
+ VM_BUG_ON(!PageSwapBacked(page));
+
+ page_cache_get(page);
+ SetPageSwapCache(page);
+ set_page_private(page, entry.val);
+
+ spin_lock_irq(&swapper_space.tree_lock);
+ error = radix_tree_insert(&swapper_space.page_tree, entry.val, page);
+ if (likely(!error)) {
+ total_swapcache_pages++;
+#ifndef CONFIG_LIMIT_PAGE_CACHE
+ __inc_zone_page_state(page, NR_FILE_PAGES);
+#endif
+ INC_CACHE_INFO(add_total);
+ }
+ spin_unlock_irq(&swapper_space.tree_lock);
+
+ if (unlikely(error)) {
+ /*
+ * Only the context which have set SWAP_HAS_CACHE flag
+ * would call add_to_swap_cache().
+ * So add_to_swap_cache() doesn't returns -EEXIST.
+ */
+ VM_BUG_ON(error == -EEXIST);
+ set_page_private(page, 0UL);
+ ClearPageSwapCache(page);
+ page_cache_release(page);
+ }
+
+ return error;
+}
+
+
+int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
+{
+ int error;
+
+ error = radix_tree_preload(gfp_mask);
+ if (!error) {
+ error = __add_to_swap_cache(page, entry);
+ radix_tree_preload_end();
+ }
+ return error;
+}
+
+/*
+ * This must be called only on pages that have
+ * been verified to be in the swap cache.
+ */
+void __delete_from_swap_cache(struct page *page)
+{
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageSwapCache(page));
+ VM_BUG_ON(PageWriteback(page));
+
+ radix_tree_delete(&swapper_space.page_tree, page_private(page));
+ set_page_private(page, 0);
+ ClearPageSwapCache(page);
+ total_swapcache_pages--;
+#ifndef CONFIG_LIMIT_PAGE_CACHE
+ __dec_zone_page_state(page, NR_FILE_PAGES);
+#endif
+ INC_CACHE_INFO(del_total);
+}
+
+/**
+ * add_to_swap - allocate swap space for a page
+ * @page: page we want to move to swap
+ *
+ * Allocate swap space for the page and add the page to the
+ * swap cache. Caller needs to hold the page lock.
+ */
+int add_to_swap(struct page *page)
+{
+ swp_entry_t entry;
+ int err;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageUptodate(page));
+
+ entry = get_swap_page();
+ if (!entry.val)
+ return 0;
+
+ if (unlikely(PageTransHuge(page)))
+ if (unlikely(split_huge_page(page))) {
+ swapcache_free(entry, NULL);
+ return 0;
+ }
+
+ /*
+ * Radix-tree node allocations from PF_MEMALLOC contexts could
+ * completely exhaust the page allocator. __GFP_NOMEMALLOC
+ * stops emergency reserves from being allocated.
+ *
+ * TODO: this could cause a theoretical memory reclaim
+ * deadlock in the swap out path.
+ */
+ /*
+ * Add it to the swap cache and mark it dirty
+ */
+ err = add_to_swap_cache(page, entry,
+ __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN);
+
+ if (!err) { /* Success */
+ SetPageDirty(page);
+ return 1;
+ } else { /* -ENOMEM radix-tree allocation failure */
+ /*
+ * add_to_swap_cache() doesn't return -EEXIST, so we can safely
+ * clear SWAP_HAS_CACHE flag.
+ */
+ swapcache_free(entry, NULL);
+ return 0;
+ }
+}
+
+/*
+ * This must be called only on pages that have
+ * been verified to be in the swap cache and locked.
+ * It will never put the page into the free list,
+ * the caller has a reference on the page.
+ */
+void delete_from_swap_cache(struct page *page)
+{
+ swp_entry_t entry;
+
+ entry.val = page_private(page);
+
+ spin_lock_irq(&swapper_space.tree_lock);
+ __delete_from_swap_cache(page);
+ spin_unlock_irq(&swapper_space.tree_lock);
+
+ swapcache_free(entry, page);
+ page_cache_release(page);
+}
+
+/*
+ * If we are the only user, then try to free up the swap cache.
+ *
+ * Its ok to check for PageSwapCache without the page lock
+ * here because we are going to recheck again inside
+ * try_to_free_swap() _with_ the lock.
+ * - Marcelo
+ */
+static inline void free_swap_cache(struct page *page)
+{
+ if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) {
+ try_to_free_swap(page);
+ unlock_page(page);
+ }
+}
+
+/*
+ * Perform a free_page(), also freeing any swap cache associated with
+ * this page if it is the last user of the page.
+ */
+void free_page_and_swap_cache(struct page *page)
+{
+ free_swap_cache(page);
+ page_cache_release(page);
+}
+
+/*
+ * Passed an array of pages, drop them all from swapcache and then release
+ * them. They are removed from the LRU and freed if this is their last use.
+ */
+void free_pages_and_swap_cache(struct page **pages, int nr)
+{
+ struct page **pagep = pages;
+
+ lru_add_drain();
+ while (nr) {
+ int todo = min(nr, PAGEVEC_SIZE);
+ int i;
+
+ for (i = 0; i < todo; i++)
+ free_swap_cache(pagep[i]);
+ release_pages(pagep, todo, 0);
+ pagep += todo;
+ nr -= todo;
+ }
+}
+
+/*
+ * 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
+ * lock getting page table operations atomic even if we drop the page
+ * lock before returning.
+ */
+struct page * lookup_swap_cache(swp_entry_t entry)
+{
+ struct page *page;
+
+ page = find_get_page(&swapper_space, entry.val);
+
+ if (page)
+ INC_CACHE_INFO(find_success);
+
+ INC_CACHE_INFO(find_total);
+ return page;
+}
+
+/*
+ * Locate a page of swap in physical memory, reserving swap cache space
+ * and reading the disk if it is not already cached.
+ * A failure return means that either the page allocation failed or that
+ * the swap entry is no longer in use.
+ */
+struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ struct page *found_page, *new_page = NULL;
+ int err;
+
+ do {
+ /*
+ * First check the swap cache. Since this is normally
+ * called after lookup_swap_cache() failed, re-calling
+ * that would confuse statistics.
+ */
+ found_page = find_get_page(&swapper_space, entry.val);
+ if (found_page)
+ break;
+
+ /*
+ * Get a new page to read into from swap.
+ */
+ if (!new_page) {
+ new_page = alloc_page_vma(gfp_mask, vma, addr);
+ if (!new_page)
+ break; /* Out of memory */
+ }
+
+ /*
+ * call radix_tree_preload() while we can wait.
+ */
+ err = radix_tree_preload(gfp_mask & GFP_KERNEL);
+ if (err)
+ break;
+
+ /*
+ * Swap entry may have been freed since our caller observed it.
+ */
+ err = swapcache_prepare(entry);
+ if (err == -EEXIST) {
+ radix_tree_preload_end();
+ /*
+ * We might race against get_swap_page() and stumble
+ * across a SWAP_HAS_CACHE swap_map entry whose page
+ * has not been brought into the swapcache yet, while
+ * the other end is scheduled away waiting on discard
+ * I/O completion at scan_swap_map().
+ *
+ * In order to avoid turning this transitory state
+ * into a permanent loop around this -EEXIST case
+ * if !CONFIG_PREEMPT and the I/O completion happens
+ * to be waiting on the CPU waitqueue where we are now
+ * busy looping, we just conditionally invoke the
+ * scheduler here, if there are some more important
+ * tasks to run.
+ */
+ cond_resched();
+ continue;
+ }
+ if (err) { /* swp entry is obsolete ? */
+ radix_tree_preload_end();
+ break;
+ }
+
+ /* May fail (-ENOMEM) if radix-tree node allocation failed. */
+ __set_page_locked(new_page);
+ SetPageSwapBacked(new_page);
+ err = __add_to_swap_cache(new_page, entry);
+ if (likely(!err)) {
+ radix_tree_preload_end();
+ /*
+ * Initiate read into locked page and return.
+ */
+ lru_cache_add_anon(new_page);
+ swap_readpage(new_page);
+ return new_page;
+ }
+ radix_tree_preload_end();
+ ClearPageSwapBacked(new_page);
+ __clear_page_locked(new_page);
+ /*
+ * add_to_swap_cache() doesn't return -EEXIST, so we can safely
+ * clear SWAP_HAS_CACHE flag.
+ */
+ swapcache_free(entry, NULL);
+ } while (err != -ENOMEM);
+
+ if (new_page)
+ page_cache_release(new_page);
+ return found_page;
+}
+
+/**
+ * swapin_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
+ *
+ * Returns the struct page for entry and addr, after queueing swapin.
+ *
+ * Primitive swap readahead code. We simply read an aligned block of
+ * (1 << page_cluster) entries in the swap area. This method is chosen
+ * because it doesn't cost us any seek time. We also make sure to queue
+ * the 'original' request together with the readahead ones...
+ *
+ * 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.
+ */
+struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ struct page *page;
+ unsigned long offset = swp_offset(entry);
+ unsigned long start_offset, end_offset;
+ unsigned long mask = (1UL << page_cluster) - 1;
+
+ /* Read a page_cluster sized and aligned cluster around offset. */
+ start_offset = offset & ~mask;
+ end_offset = offset | mask;
+ if (!start_offset) /* First page is swap header. */
+ start_offset++;
+
+ for (offset = start_offset; offset <= end_offset ; offset++) {
+ /* Ok, do the async read-ahead now */
+ page = read_swap_cache_async(swp_entry(swp_type(entry), offset),
+ gfp_mask, vma, addr);
+ if (!page)
+ continue;
+ page_cache_release(page);
+ }
+ lru_add_drain(); /* Push any new pages onto the LRU now */
+ return read_swap_cache_async(entry, gfp_mask, vma, addr);
+}