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-rw-r--r--mm/page-writeback.c160
1 files changed, 147 insertions, 13 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 555752907dc3..c0d4ce144dec 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -30,6 +30,8 @@
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
+#include <linux/buffer_head.h>
+#include <linux/pagevec.h>
/*
* The maximum number of pages to writeout in a single bdflush/kupdate
@@ -46,7 +48,6 @@
*/
static long ratelimit_pages = 32;
-static long total_pages; /* The total number of pages in the machine. */
static int dirty_exceeded __cacheline_aligned_in_smp; /* Dirty mem may be over limit */
/*
@@ -126,7 +127,7 @@ get_dirty_limits(long *pbackground, long *pdirty,
int unmapped_ratio;
long background;
long dirty;
- unsigned long available_memory = total_pages;
+ unsigned long available_memory = vm_total_pages;
struct task_struct *tsk;
#ifdef CONFIG_HIGHMEM
@@ -141,7 +142,7 @@ get_dirty_limits(long *pbackground, long *pdirty,
unmapped_ratio = 100 - ((global_page_state(NR_FILE_MAPPED) +
global_page_state(NR_ANON_PAGES)) * 100) /
- total_pages;
+ vm_total_pages;
dirty_ratio = vm_dirty_ratio;
if (dirty_ratio > unmapped_ratio / 2)
@@ -502,9 +503,9 @@ void laptop_sync_completion(void)
* will write six megabyte chunks, max.
*/
-static void set_ratelimit(void)
+void writeback_set_ratelimit(void)
{
- ratelimit_pages = total_pages / (num_online_cpus() * 32);
+ ratelimit_pages = vm_total_pages / (num_online_cpus() * 32);
if (ratelimit_pages < 16)
ratelimit_pages = 16;
if (ratelimit_pages * PAGE_CACHE_SIZE > 4096 * 1024)
@@ -514,7 +515,7 @@ static void set_ratelimit(void)
static int __cpuinit
ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
{
- set_ratelimit();
+ writeback_set_ratelimit();
return 0;
}
@@ -533,9 +534,7 @@ void __init page_writeback_init(void)
long buffer_pages = nr_free_buffer_pages();
long correction;
- total_pages = nr_free_pagecache_pages();
-
- correction = (100 * 4 * buffer_pages) / total_pages;
+ correction = (100 * 4 * buffer_pages) / vm_total_pages;
if (correction < 100) {
dirty_background_ratio *= correction;
@@ -549,10 +548,143 @@ void __init page_writeback_init(void)
vm_dirty_ratio = 1;
}
mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
- set_ratelimit();
+ writeback_set_ratelimit();
register_cpu_notifier(&ratelimit_nb);
}
+/**
+ * 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.
+ *
+ * If a page is already under I/O, generic_writepages() 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)
+{
+ 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;
+ pgoff_t end; /* Inclusive */
+ int scanned = 0;
+ int range_whole = 0;
+
+ if (wbc->nonblocking && bdi_write_congested(bdi)) {
+ wbc->encountered_congestion = 1;
+ 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 */
+ 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;
+ }
+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;
+
+ 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
+ */
+ lock_page(page);
+
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ continue;
+ }
+
+ if (!wbc->range_cyclic && page->index > end) {
+ done = 1;
+ unlock_page(page);
+ continue;
+ }
+
+ 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;
+ }
+
+ ret = (*writepage)(page, wbc);
+ if (ret) {
+ if (ret == -ENOSPC)
+ set_bit(AS_ENOSPC, &mapping->flags);
+ else
+ set_bit(AS_EIO, &mapping->flags);
+ }
+
+ if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE))
+ unlock_page(page);
+ if (ret || (--(wbc->nr_to_write) <= 0))
+ done = 1;
+ if (wbc->nonblocking && bdi_write_congested(bdi)) {
+ wbc->encountered_congestion = 1;
+ done = 1;
+ }
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+ if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+ mapping->writeback_index = index;
+ return ret;
+}
+
+EXPORT_SYMBOL(generic_writepages);
+
int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
int ret;
@@ -675,9 +807,11 @@ int fastcall set_page_dirty(struct page *page)
if (likely(mapping)) {
int (*spd)(struct page *) = mapping->a_ops->set_page_dirty;
- if (spd)
- return (*spd)(page);
- return __set_page_dirty_buffers(page);
+#ifdef CONFIG_BLOCK
+ if (!spd)
+ spd = __set_page_dirty_buffers;
+#endif
+ return (*spd)(page);
}
if (!PageDirty(page)) {
if (!TestSetPageDirty(page))