* We make sure that the background writeout level is below the adjusted
* clamping level.
*/
+
+static unsigned long highmem_dirtyable_memory(unsigned long total)
+{
+#ifdef CONFIG_HIGHMEM
+ int node;
+ unsigned long x = 0;
+
+ for_each_online_node(node) {
+ struct zone *z =
+ &NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
+
+ x += zone_page_state(z, NR_FREE_PAGES)
+ + zone_page_state(z, NR_INACTIVE)
+ + zone_page_state(z, NR_ACTIVE);
+ }
+ /*
+ * Make sure that the number of highmem pages is never larger
+ * than the number of the total dirtyable memory. This can only
+ * occur in very strange VM situations but we want to make sure
+ * that this does not occur.
+ */
+ return min(x, total);
+#else
+ return 0;
+#endif
+}
+
+static unsigned long determine_dirtyable_memory(void)
+{
+ unsigned long x;
+
+ x = global_page_state(NR_FREE_PAGES)
+ + global_page_state(NR_INACTIVE)
+ + global_page_state(NR_ACTIVE);
+ x -= highmem_dirtyable_memory(x);
+ return x + 1; /* Ensure that we never return 0 */
+}
+
static void
get_dirty_limits(long *pbackground, long *pdirty,
struct address_space *mapping)
int unmapped_ratio;
long background;
long dirty;
- unsigned long available_memory = vm_total_pages;
+ unsigned long available_memory = determine_dirtyable_memory();
struct task_struct *tsk;
-#ifdef CONFIG_HIGHMEM
- /*
- * We always exclude high memory from our count.
- */
- available_memory -= totalhigh_pages;
-#endif
-
-
unmapped_ratio = 100 - ((global_page_state(NR_FILE_MAPPED) +
global_page_state(NR_ANON_PAGES)) * 100) /
- vm_total_pages;
+ available_memory;
dirty_ratio = vm_dirty_ratio;
if (dirty_ratio > unmapped_ratio / 2)
* sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
*/
int dirty_writeback_centisecs_handler(ctl_table *table, int write,
- struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
+ struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
proc_dointvec_userhz_jiffies(table, write, file, buffer, length, ppos);
- if (dirty_writeback_interval) {
- mod_timer(&wb_timer,
- jiffies + dirty_writeback_interval);
- } else {
+ if (dirty_writeback_interval)
+ mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
+ else
del_timer(&wb_timer);
- }
return 0;
}
}
/**
- * generic_writepages - walk the list of dirty pages of the given address space and writepage() all of them.
+ * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
* @mapping: address space structure to write
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
+ * @writepage: function called for each page
+ * @data: data passed to writepage function
*
- * This is a library function, which implements the writepages()
- * address_space_operation.
- *
- * If a page is already under I/O, generic_writepages() skips it, even
+ * If a page is already under I/O, write_cache_pages() skips it, even
* if it's dirty. This is desirable behaviour for memory-cleaning writeback,
* but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
* and msync() need to guarantee that all the data which was dirty at the time
* the call was made get new I/O started against them. If wbc->sync_mode is
* WB_SYNC_ALL then we were called for data integrity and we must wait for
* existing IO to complete.
- *
- * Derived from mpage_writepages() - if you fix this you should check that
- * also!
*/
-int generic_writepages(struct address_space *mapping,
- struct writeback_control *wbc)
+int write_cache_pages(struct address_space *mapping,
+ struct writeback_control *wbc, writepage_t writepage,
+ void *data)
{
struct backing_dev_info *bdi = mapping->backing_dev_info;
int ret = 0;
int done = 0;
- int (*writepage)(struct page *page, struct writeback_control *wbc);
struct pagevec pvec;
int nr_pages;
pgoff_t index;
return 0;
}
- writepage = mapping->a_ops->writepage;
-
- /* deal with chardevs and other special file */
- if (!writepage)
- return 0;
-
pagevec_init(&pvec, 0);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
continue;
}
- ret = (*writepage)(page, wbc);
- if (ret) {
- if (ret == -ENOSPC)
- set_bit(AS_ENOSPC, &mapping->flags);
- else
- set_bit(AS_EIO, &mapping->flags);
- }
+ ret = (*writepage)(page, wbc, data);
if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE))
unlock_page(page);
mapping->writeback_index = index;
return ret;
}
+EXPORT_SYMBOL(write_cache_pages);
+
+/*
+ * Function used by generic_writepages to call the real writepage
+ * function and set the mapping flags on error
+ */
+static int __writepage(struct page *page, struct writeback_control *wbc,
+ void *data)
+{
+ struct address_space *mapping = data;
+ int ret = mapping->a_ops->writepage(page, wbc);
+ mapping_set_error(mapping, ret);
+ return ret;
+}
+
+/**
+ * generic_writepages - walk the list of dirty pages of the given address space and writepage() all of them.
+ * @mapping: address space structure to write
+ * @wbc: subtract the number of written pages from *@wbc->nr_to_write
+ *
+ * This is a library function, which implements the writepages()
+ * address_space_operation.
+ */
+int generic_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ /* deal with chardevs and other special file */
+ if (!mapping->a_ops->writepage)
+ return 0;
+
+ return write_cache_pages(mapping, wbc, __writepage, mapping);
+}
EXPORT_SYMBOL(generic_writepages);
mapping2 = page_mapping(page);
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
+ WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
if (mapping_cap_account_dirty(mapping)) {
__inc_zone_page_state(page, NR_FILE_DIRTY);
task_io_account_write(PAGE_CACHE_SIZE);
{
struct address_space *mapping = page_mapping(page);
+ BUG_ON(!PageLocked(page));
+
+ ClearPageReclaim(page);
if (mapping && mapping_cap_account_dirty(mapping)) {
/*
* Yes, Virginia, this is indeed insane.
* We basically use the page "master dirty bit"
* as a serialization point for all the different
* threads doing their things.
- *
- * FIXME! We still have a race here: if somebody
- * adds the page back to the page tables in
- * between the "page_mkclean()" and the "TestClearPageDirty()",
- * we might have it mapped without the dirty bit set.
*/
if (page_mkclean(page))
set_page_dirty(page);
+ /*
+ * We carefully synchronise fault handlers against
+ * installing a dirty pte and marking the page dirty
+ * at this point. We do this by having them hold the
+ * page lock at some point after installing their
+ * pte, but before marking the page dirty.
+ * Pages are always locked coming in here, so we get
+ * the desired exclusion. See mm/memory.c:do_wp_page()
+ * for more comments.
+ */
if (TestClearPageDirty(page)) {
dec_zone_page_state(page, NR_FILE_DIRTY);
return 1;
} else {
ret = TestClearPageWriteback(page);
}
+ if (ret)
+ dec_zone_page_state(page, NR_WRITEBACK);
return ret;
}
} else {
ret = TestSetPageWriteback(page);
}
+ if (!ret)
+ inc_zone_page_state(page, NR_WRITEBACK);
return ret;
}
git.openpandora.org / pandora-kernel.git / blobdiff