* Contains functions related to writing back dirty pages at the
* address_space level.
*
- * 10Apr2002 akpm@zip.com.au
+ * 10Apr2002 Andrew Morton
* Initial version
*/
int dirty_background_ratio = 5;
/*
+ * dirty_background_bytes starts at 0 (disabled) so that it is a function of
+ * dirty_background_ratio * the amount of dirtyable memory
+ */
+unsigned long dirty_background_bytes;
+
+/*
* free highmem will not be subtracted from the total free memory
* for calculating free ratios if vm_highmem_is_dirtyable is true
*/
int vm_dirty_ratio = 10;
/*
+ * vm_dirty_bytes starts at 0 (disabled) so that it is a function of
+ * vm_dirty_ratio * the amount of dirtyable memory
+ */
+unsigned long vm_dirty_bytes;
+
+/*
* The interval between `kupdate'-style writebacks, in jiffies
*/
int dirty_writeback_interval = 5 * HZ;
static struct prop_descriptor vm_completions;
static struct prop_descriptor vm_dirties;
-static unsigned long determine_dirtyable_memory(void);
-
/*
* couple the period to the dirty_ratio:
*
{
unsigned long dirty_total;
- dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) / 100;
+ if (vm_dirty_bytes)
+ dirty_total = vm_dirty_bytes / PAGE_SIZE;
+ else
+ dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
+ 100;
return 2 + ilog2(dirty_total - 1);
}
/*
- * update the period when the dirty ratio changes.
+ * update the period when the dirty threshold changes.
*/
+static void update_completion_period(void)
+{
+ int shift = calc_period_shift();
+ prop_change_shift(&vm_completions, shift);
+ prop_change_shift(&vm_dirties, shift);
+}
+
+int dirty_background_ratio_handler(struct ctl_table *table, int write,
+ struct file *filp, void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+ if (ret == 0 && write)
+ dirty_background_bytes = 0;
+ return ret;
+}
+
+int dirty_background_bytes_handler(struct ctl_table *table, int write,
+ struct file *filp, void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+ if (ret == 0 && write)
+ dirty_background_ratio = 0;
+ return ret;
+}
+
int dirty_ratio_handler(struct ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int old_ratio = vm_dirty_ratio;
- int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+ int ret;
+
+ ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
if (ret == 0 && write && vm_dirty_ratio != old_ratio) {
- int shift = calc_period_shift();
- prop_change_shift(&vm_completions, shift);
- prop_change_shift(&vm_dirties, shift);
+ update_completion_period();
+ vm_dirty_bytes = 0;
+ }
+ return ret;
+}
+
+
+int dirty_bytes_handler(struct ctl_table *table, int write,
+ struct file *filp, void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ unsigned long old_bytes = vm_dirty_bytes;
+ int ret;
+
+ ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+ if (ret == 0 && write && vm_dirty_bytes != old_bytes) {
+ update_completion_period();
+ vm_dirty_ratio = 0;
}
return ret;
}
bdi->max_prop_frac);
}
-static inline void task_dirty_inc(struct task_struct *tsk)
+void bdi_writeout_inc(struct backing_dev_info *bdi)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __bdi_writeout_inc(bdi);
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(bdi_writeout_inc);
+
+void task_dirty_inc(struct task_struct *tsk)
{
prop_inc_single(&vm_dirties, &tsk->dirties);
}
avail_dirty = dirty -
(global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_WRITEBACK) +
- global_page_state(NR_UNSTABLE_NFS));
+ global_page_state(NR_UNSTABLE_NFS) +
+ global_page_state(NR_WRITEBACK_TEMP));
if (avail_dirty < 0)
avail_dirty = 0;
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);
+ x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
}
/*
* Make sure that the number of highmem pages is never larger
#endif
}
-static unsigned long determine_dirtyable_memory(void)
+/**
+ * determine_dirtyable_memory - amount of memory that may be used
+ *
+ * Returns the numebr of pages that can currently be freed and used
+ * by the kernel for direct mappings.
+ */
+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 = global_page_state(NR_FREE_PAGES) + global_lru_pages();
if (!vm_highmem_is_dirtyable)
x -= highmem_dirtyable_memory(x);
}
void
-get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
- struct backing_dev_info *bdi)
+get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
+ unsigned long *pbdi_dirty, struct backing_dev_info *bdi)
{
- int background_ratio; /* Percentages */
- int dirty_ratio;
- long background;
- long dirty;
+ unsigned long background;
+ unsigned long dirty;
unsigned long available_memory = determine_dirtyable_memory();
struct task_struct *tsk;
- dirty_ratio = vm_dirty_ratio;
- if (dirty_ratio < 5)
- dirty_ratio = 5;
+ if (vm_dirty_bytes)
+ dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
+ else {
+ int dirty_ratio;
- background_ratio = dirty_background_ratio;
- if (background_ratio >= dirty_ratio)
- background_ratio = dirty_ratio / 2;
+ dirty_ratio = vm_dirty_ratio;
+ if (dirty_ratio < 5)
+ dirty_ratio = 5;
+ dirty = (dirty_ratio * available_memory) / 100;
+ }
+
+ if (dirty_background_bytes)
+ background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
+ else
+ background = (dirty_background_ratio * available_memory) / 100;
- background = (background_ratio * available_memory) / 100;
- dirty = (dirty_ratio * available_memory) / 100;
+ if (background >= dirty)
+ background = dirty / 2;
tsk = current;
if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) {
background += background / 4;
{
long nr_reclaimable, bdi_nr_reclaimable;
long nr_writeback, bdi_nr_writeback;
- long background_thresh;
- long dirty_thresh;
- long bdi_thresh;
+ unsigned long background_thresh;
+ unsigned long dirty_thresh;
+ unsigned long bdi_thresh;
unsigned long pages_written = 0;
unsigned long write_chunk = sync_writeback_pages();
void throttle_vm_writeout(gfp_t gfp_mask)
{
- long background_thresh;
- long dirty_thresh;
+ unsigned long background_thresh;
+ unsigned long dirty_thresh;
for ( ; ; ) {
get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
};
for ( ; ; ) {
- long background_thresh;
- long dirty_thresh;
+ unsigned long background_thresh;
+ unsigned long dirty_thresh;
get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
if (global_page_state(NR_FILE_DIRTY) +
int done = 0;
struct pagevec pvec;
int nr_pages;
+ pgoff_t uninitialized_var(writeback_index);
pgoff_t index;
pgoff_t end; /* Inclusive */
- int scanned = 0;
+ pgoff_t done_index;
+ int cycled;
int range_whole = 0;
+ long nr_to_write = wbc->nr_to_write;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
pagevec_init(&pvec, 0);
if (wbc->range_cyclic) {
- index = mapping->writeback_index; /* Start from prev offset */
+ writeback_index = mapping->writeback_index; /* prev offset */
+ index = writeback_index;
+ if (index == 0)
+ cycled = 1;
+ else
+ cycled = 0;
end = -1;
} else {
index = wbc->range_start >> PAGE_CACHE_SHIFT;
end = wbc->range_end >> PAGE_CACHE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
- scanned = 1;
+ cycled = 1; /* ignore range_cyclic tests */
}
retry:
- while (!done && (index <= end) &&
- (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
- PAGECACHE_TAG_DIRTY,
- min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
- unsigned i;
+ done_index = index;
+ while (!done && (index <= end)) {
+ int i;
+
+ nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
+ if (nr_pages == 0)
+ break;
- scanned = 1;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
/*
- * At this point we hold neither mapping->tree_lock nor
- * lock on the page itself: the page may be truncated or
- * invalidated (changing page->mapping to NULL), or even
- * swizzled back from swapper_space to tmpfs file
- * mapping
+ * At this point, the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or
+ * even swizzled back from swapper_space to tmpfs file
+ * mapping. However, page->index will not change
+ * because we have a reference on the page.
*/
+ if (page->index > end) {
+ /*
+ * can't be range_cyclic (1st pass) because
+ * end == -1 in that case.
+ */
+ done = 1;
+ break;
+ }
+
+ done_index = page->index + 1;
+
lock_page(page);
+ /*
+ * Page truncated or invalidated. We can freely skip it
+ * then, even for data integrity operations: the page
+ * has disappeared concurrently, so there could be no
+ * real expectation of this data interity operation
+ * even if there is now a new, dirty page at the same
+ * pagecache address.
+ */
if (unlikely(page->mapping != mapping)) {
+continue_unlock:
unlock_page(page);
continue;
}
- if (!wbc->range_cyclic && page->index > end) {
- done = 1;
- unlock_page(page);
- continue;
+ if (!PageDirty(page)) {
+ /* someone wrote it for us */
+ goto continue_unlock;
}
- if (wbc->sync_mode != WB_SYNC_NONE)
- wait_on_page_writeback(page);
-
- if (PageWriteback(page) ||
- !clear_page_dirty_for_io(page)) {
- unlock_page(page);
- continue;
+ if (PageWriteback(page)) {
+ if (wbc->sync_mode != WB_SYNC_NONE)
+ wait_on_page_writeback(page);
+ else
+ goto continue_unlock;
}
- ret = (*writepage)(page, wbc, data);
+ BUG_ON(PageWriteback(page));
+ if (!clear_page_dirty_for_io(page))
+ goto continue_unlock;
- if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
- unlock_page(page);
- ret = 0;
+ ret = (*writepage)(page, wbc, data);
+ if (unlikely(ret)) {
+ if (ret == AOP_WRITEPAGE_ACTIVATE) {
+ unlock_page(page);
+ ret = 0;
+ } else {
+ /*
+ * done_index is set past this page,
+ * so media errors will not choke
+ * background writeout for the entire
+ * file. This has consequences for
+ * range_cyclic semantics (ie. it may
+ * not be suitable for data integrity
+ * writeout).
+ */
+ done = 1;
+ break;
+ }
+ }
+
+ if (nr_to_write > 0) {
+ nr_to_write--;
+ if (nr_to_write == 0 &&
+ wbc->sync_mode == WB_SYNC_NONE) {
+ /*
+ * We stop writing back only if we are
+ * not doing integrity sync. In case of
+ * integrity sync we have to keep going
+ * because someone may be concurrently
+ * dirtying pages, and we might have
+ * synced a lot of newly appeared dirty
+ * pages, but have not synced all of the
+ * old dirty pages.
+ */
+ done = 1;
+ break;
+ }
}
- if (ret || (--(wbc->nr_to_write) <= 0))
- done = 1;
+
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
done = 1;
+ break;
}
}
pagevec_release(&pvec);
cond_resched();
}
- if (!scanned && !done) {
+ if (!cycled && !done) {
/*
+ * range_cyclic:
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
- scanned = 1;
+ cycled = 1;
index = 0;
+ end = writeback_index - 1;
goto retry;
}
- if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
- mapping->writeback_index = index;
+ if (!wbc->no_nrwrite_index_update) {
+ if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
+ mapping->writeback_index = done_index;
+ wbc->nr_to_write = nr_to_write;
+ }
+
return ret;
}
EXPORT_SYMBOL(write_cache_pages);
if (!mapping)
return 1;
- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
mapping2 = page_mapping(page);
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
__inc_zone_page_state(page, NR_FILE_DIRTY);
__inc_bdi_stat(mapping->backing_dev_info,
BDI_RECLAIMABLE);
+ task_dirty_inc(current);
task_io_account_write(PAGE_CACHE_SIZE);
}
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
if (mapping->host) {
/* !PageAnon && !swapper_space */
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
* If the mapping doesn't provide a set_page_dirty a_op, then
* just fall through and assume that it wants buffer_heads.
*/
-static int __set_page_dirty(struct page *page)
+int set_page_dirty(struct page *page)
{
struct address_space *mapping = page_mapping(page);
}
return 0;
}
-
-int set_page_dirty(struct page *page)
-{
- int ret = __set_page_dirty(page);
- if (ret)
- task_dirty_inc(current);
- return ret;
-}
EXPORT_SYMBOL(set_page_dirty);
/*
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;
- write_lock_irqsave(&mapping->tree_lock, flags);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
ret = TestClearPageWriteback(page);
if (ret) {
radix_tree_tag_clear(&mapping->page_tree,
__bdi_writeout_inc(bdi);
}
}
- write_unlock_irqrestore(&mapping->tree_lock, flags);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
ret = TestClearPageWriteback(page);
}
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;
- write_lock_irqsave(&mapping->tree_lock, flags);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
ret = TestSetPageWriteback(page);
if (!ret) {
radix_tree_tag_set(&mapping->page_tree,
radix_tree_tag_clear(&mapping->page_tree,
page_index(page),
PAGECACHE_TAG_DIRTY);
- write_unlock_irqrestore(&mapping->tree_lock, flags);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
ret = TestSetPageWriteback(page);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff