Exemplo n.º 1
0
Buddy::Buddy (mword phys, mword virt, mword f_addr, size_t size)
{
    // Compute maximum aligned block size
    unsigned long bit = bit_scan_reverse (size);

    // Compute maximum aligned physical block address (base)
    base = phys_to_virt (align_up (phys, 1ul << bit));

    // Convert block size to page order
    order = bit + 1 - PAGE_BITS;

    trace (TRACE_MEMORY, "POOL: %#010lx-%#010lx O:%lu",
           phys,
           phys + size,
           order);

    // Allocate block-list heads
    size -= order * sizeof *head;
    head = reinterpret_cast<Block *>(virt + size);

    // Allocate block-index storage
    size -= size / (PAGE_SIZE + sizeof *index) * sizeof *index;
    size &= ~PAGE_MASK;
    min_idx = page_to_index (virt);
    max_idx = page_to_index (virt + size);
    index = reinterpret_cast<Block *>(virt + size) - min_idx;

    for (unsigned i = 0; i < order; i++)
        head[i].next = head[i].prev = head + i;

    for (mword i = f_addr; i < virt + size; i += PAGE_SIZE)
        free (i);
}
Exemplo n.º 2
0
/*
 * Free physically contiguous memory region.
 * @param virt     Linear block base address
 */
void Buddy::free (mword virt)
{
    signed long idx = page_to_index (virt);

    // Ensure virt is within allocator range
    assert (idx >= min_idx && idx < max_idx);

    Block *block = index_to_block (idx);

    // Ensure block is marked as used
    assert (block->tag == Block::Used);

    // Ensure corresponding physical block is order-aligned
    assert ((virt_to_phys (virt) & ((1ul << (block->ord + PAGE_BITS)) - 1)) == 0);

    Lock_guard <Spinlock> guard (lock);

    unsigned short ord;
    for (ord = block->ord; ord < order - 1; ord++) {

        // Compute block index and corresponding buddy index
        signed long block_idx = block_to_index (block);
        signed long buddy_idx = block_idx ^ (1ul << ord);

        // Buddy outside mempool
        if (buddy_idx < min_idx || buddy_idx >= max_idx)
            break;

        Block *buddy = index_to_block (buddy_idx);

        // Buddy in use or fragmented
        if (buddy->tag == Block::Used || buddy->ord != ord)
            break;

        // Dequeue buddy from block list
        buddy->prev->next = buddy->next;
        buddy->next->prev = buddy->prev;

        // Merge block with buddy
        if (buddy < block)
            block = buddy;
    }

    block->ord = ord;
    block->tag = Block::Free;

    // Enqueue final-size block
    Block *h = head + ord;
    block->prev = h;
    block->next = h->next;
    block->next->prev = h->next = block;
}
Exemplo n.º 3
0
int bio_add_page(bio_t *bio, struct page *page, unsigned int rw)
{
    struct bio_vec *bv = bio->bi_vec;
    bv = &bio->bi_vec[bio->bi_idex++];
    bv->bv_page = page;
    bio->bi_idex++;
    bio->bi_size += PAGE_SIZE;
    bio->bi_rw = rw ;
    bio->bi_front_nr = page_to_index(page);
    bio->bi_back_nr = bio->bi_front_nr;

    return 0;
}
Exemplo n.º 4
0
/**
 * invalidate_inode_pages2_range - remove range of pages from an address_space
 * @mapping: the address_space
 * @start: the page offset 'from' which to invalidate
 * @end: the page offset 'to' which to invalidate (inclusive)
 *
 * Any pages which are found to be mapped into pagetables are unmapped prior to
 * invalidation.
 *
 * Returns -EBUSY if any pages could not be invalidated.
 */
int invalidate_inode_pages2_range(struct address_space *mapping,
				  pgoff_t start, pgoff_t end)
{
	pgoff_t indices[PAGEVEC_SIZE];
	struct pagevec pvec;
	pgoff_t index;
	int i;
	int ret = 0;
	int ret2 = 0;
	int did_range_unmap = 0;

	cleancache_invalidate_inode(mapping);
	pagevec_init(&pvec, 0);
	index = start;
	while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
			indices)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			/* We rely upon deletion not changing page->index */
			index = indices[i];
			if (index > end)
				break;

			if (radix_tree_exceptional_entry(page)) {
				clear_exceptional_entry(mapping, index, page);
				continue;
			}

			lock_page(page);
			WARN_ON(page_to_index(page) != index);
			if (page->mapping != mapping) {
				unlock_page(page);
				continue;
			}
			wait_on_page_writeback(page);
			if (page_mapped(page)) {
				if (!did_range_unmap) {
					/*
					 * Zap the rest of the file in one hit.
					 */
					unmap_mapping_range(mapping,
					   (loff_t)index << PAGE_SHIFT,
					   (loff_t)(1 + end - index)
							 << PAGE_SHIFT,
							 0);
					did_range_unmap = 1;
				} else {
					/*
					 * Just zap this page
					 */
					unmap_mapping_range(mapping,
					   (loff_t)index << PAGE_SHIFT,
					   PAGE_SIZE, 0);
				}
			}
			BUG_ON(page_mapped(page));
			ret2 = do_launder_page(mapping, page);
			if (ret2 == 0) {
				if (!invalidate_complete_page2(mapping, page))
					ret2 = -EBUSY;
			}
			if (ret2 < 0)
				ret = ret2;
			unlock_page(page);
		}
		pagevec_remove_exceptionals(&pvec);
		pagevec_release(&pvec);
		cond_resched();
		index++;
	}
	cleancache_invalidate_inode(mapping);
	return ret;
}
Exemplo n.º 5
0
/**
 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
 * @mapping: the address_space which holds the pages to invalidate
 * @start: the offset 'from' which to invalidate
 * @end: the offset 'to' which to invalidate (inclusive)
 *
 * This function only removes the unlocked pages, if you want to
 * remove all the pages of one inode, you must call truncate_inode_pages.
 *
 * invalidate_mapping_pages() will not block on IO activity. It will not
 * invalidate pages which are dirty, locked, under writeback or mapped into
 * pagetables.
 */
unsigned long invalidate_mapping_pages(struct address_space *mapping,
		pgoff_t start, pgoff_t end)
{
	pgoff_t indices[PAGEVEC_SIZE];
	struct pagevec pvec;
	pgoff_t index = start;
	unsigned long ret;
	unsigned long count = 0;
	int i;

	pagevec_init(&pvec, 0);
	while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
			indices)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			/* We rely upon deletion not changing page->index */
			index = indices[i];
			if (index > end)
				break;

			if (radix_tree_exceptional_entry(page)) {
				clear_exceptional_entry(mapping, index, page);
				continue;
			}

			if (!trylock_page(page))
				continue;

			WARN_ON(page_to_index(page) != index);

			/* Middle of THP: skip */
			if (PageTransTail(page)) {
				unlock_page(page);
				continue;
			} else if (PageTransHuge(page)) {
				index += HPAGE_PMD_NR - 1;
				i += HPAGE_PMD_NR - 1;
				/* 'end' is in the middle of THP */
				if (index ==  round_down(end, HPAGE_PMD_NR))
					continue;
			}

			ret = invalidate_inode_page(page);
			unlock_page(page);
			/*
			 * Invalidation is a hint that the page is no longer
			 * of interest and try to speed up its reclaim.
			 */
			if (!ret)
				deactivate_file_page(page);
			count += ret;
		}
		pagevec_remove_exceptionals(&pvec);
		pagevec_release(&pvec);
		cond_resched();
		index++;
	}
	return count;
}
Exemplo n.º 6
0
/**
 * truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets
 * @mapping: mapping to truncate
 * @lstart: offset from which to truncate
 * @lend: offset to which to truncate (inclusive)
 *
 * Truncate the page cache, removing the pages that are between
 * specified offsets (and zeroing out partial pages
 * if lstart or lend + 1 is not page aligned).
 *
 * Truncate takes two passes - the first pass is nonblocking.  It will not
 * block on page locks and it will not block on writeback.  The second pass
 * will wait.  This is to prevent as much IO as possible in the affected region.
 * The first pass will remove most pages, so the search cost of the second pass
 * is low.
 *
 * We pass down the cache-hot hint to the page freeing code.  Even if the
 * mapping is large, it is probably the case that the final pages are the most
 * recently touched, and freeing happens in ascending file offset order.
 *
 * Note that since ->invalidatepage() accepts range to invalidate
 * truncate_inode_pages_range is able to handle cases where lend + 1 is not
 * page aligned properly.
 */
void truncate_inode_pages_range(struct address_space *mapping,
				loff_t lstart, loff_t lend)
{
	pgoff_t		start;		/* inclusive */
	pgoff_t		end;		/* exclusive */
	unsigned int	partial_start;	/* inclusive */
	unsigned int	partial_end;	/* exclusive */
	struct pagevec	pvec;
	pgoff_t		indices[PAGEVEC_SIZE];
	pgoff_t		index;
	int		i;

	cleancache_invalidate_inode(mapping);
	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
		return;

	/* Offsets within partial pages */
	partial_start = lstart & (PAGE_SIZE - 1);
	partial_end = (lend + 1) & (PAGE_SIZE - 1);

	/*
	 * 'start' and 'end' always covers the range of pages to be fully
	 * truncated. Partial pages are covered with 'partial_start' at the
	 * start of the range and 'partial_end' at the end of the range.
	 * Note that 'end' is exclusive while 'lend' is inclusive.
	 */
	start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (lend == -1)
		/*
		 * lend == -1 indicates end-of-file so we have to set 'end'
		 * to the highest possible pgoff_t and since the type is
		 * unsigned we're using -1.
		 */
		end = -1;
	else
		end = (lend + 1) >> PAGE_SHIFT;

	pagevec_init(&pvec, 0);
	index = start;
	while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
			min(end - index, (pgoff_t)PAGEVEC_SIZE),
			indices)) {
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			/* We rely upon deletion not changing page->index */
			index = indices[i];
			if (index >= end)
				break;

			if (radix_tree_exceptional_entry(page)) {
				clear_exceptional_entry(mapping, index, page);
				continue;
			}

			if (!trylock_page(page))
				continue;
			WARN_ON(page_to_index(page) != index);
			if (PageWriteback(page)) {
				unlock_page(page);
				continue;
			}
			truncate_inode_page(mapping, page);
			unlock_page(page);
		}
		pagevec_remove_exceptionals(&pvec);
		pagevec_release(&pvec);
		cond_resched();
		index++;
	}

	if (partial_start) {
		struct page *page = find_lock_page(mapping, start - 1);
		if (page) {
			unsigned int top = PAGE_SIZE;
			if (start > end) {
				/* Truncation within a single page */
				top = partial_end;
				partial_end = 0;
			}
			wait_on_page_writeback(page);
			zero_user_segment(page, partial_start, top);
			cleancache_invalidate_page(mapping, page);
			if (page_has_private(page))
				do_invalidatepage(page, partial_start,
						  top - partial_start);
			unlock_page(page);
			put_page(page);
		}
	}
	if (partial_end) {
		struct page *page = find_lock_page(mapping, end);
		if (page) {
			wait_on_page_writeback(page);
			zero_user_segment(page, 0, partial_end);
			cleancache_invalidate_page(mapping, page);
			if (page_has_private(page))
				do_invalidatepage(page, 0,
						  partial_end);
			unlock_page(page);
			put_page(page);
		}
	}
	/*
	 * If the truncation happened within a single page no pages
	 * will be released, just zeroed, so we can bail out now.
	 */
	if (start >= end)
		return;

	index = start;
	for ( ; ; ) {
		cond_resched();
		if (!pagevec_lookup_entries(&pvec, mapping, index,
			min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) {
			/* If all gone from start onwards, we're done */
			if (index == start)
				break;
			/* Otherwise restart to make sure all gone */
			index = start;
			continue;
		}
		if (index == start && indices[0] >= end) {
			/* All gone out of hole to be punched, we're done */
			pagevec_remove_exceptionals(&pvec);
			pagevec_release(&pvec);
			break;
		}
		for (i = 0; i < pagevec_count(&pvec); i++) {
			struct page *page = pvec.pages[i];

			/* We rely upon deletion not changing page->index */
			index = indices[i];
			if (index >= end) {
				/* Restart punch to make sure all gone */
				index = start - 1;
				break;
			}

			if (radix_tree_exceptional_entry(page)) {
				clear_exceptional_entry(mapping, index, page);
				continue;
			}

			lock_page(page);
			WARN_ON(page_to_index(page) != index);
			wait_on_page_writeback(page);
			truncate_inode_page(mapping, page);
			unlock_page(page);
		}
		pagevec_remove_exceptionals(&pvec);
		pagevec_release(&pvec);
		index++;
	}
	cleancache_invalidate_inode(mapping);
}
Exemplo n.º 7
0
 void mem_pool::mem_pool_impl::free_page(const char *page)
 {
   assert(page != 0);
   int index = page_to_index(page);
   free_page(index);
 }