/*
- * mm/page-writeback.c.
+ * mm/page-writeback.c
*
* Copyright (C) 2002, Linus Torvalds.
*
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
#include <linux/mpage.h>
+#include <linux/rmap.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#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
*/
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 */
/*
static void background_writeout(unsigned long _min_pages);
-struct writeback_state
-{
- unsigned long nr_dirty;
- unsigned long nr_unstable;
- unsigned long nr_mapped;
- unsigned long nr_writeback;
-};
-
-static void get_writeback_state(struct writeback_state *wbs)
-{
- wbs->nr_dirty = read_page_state(nr_dirty);
- wbs->nr_unstable = read_page_state(nr_unstable);
- wbs->nr_mapped = global_page_state(NR_FILE_MAPPED);
- wbs->nr_writeback = read_page_state(nr_writeback);
-}
-
/*
* Work out the current dirty-memory clamping and background writeout
* thresholds.
* clamping level.
*/
static void
-get_dirty_limits(struct writeback_state *wbs, long *pbackground, long *pdirty,
- struct address_space *mapping)
+get_dirty_limits(long *pbackground, long *pdirty,
+ struct address_space *mapping)
{
int background_ratio; /* Percentages */
int dirty_ratio;
int unmapped_ratio;
long background;
long dirty;
- unsigned long available_memory = total_pages;
+ unsigned long available_memory = vm_total_pages;
struct task_struct *tsk;
- get_writeback_state(wbs);
-
#ifdef CONFIG_HIGHMEM
/*
* If this mapping can only allocate from low memory,
#endif
- unmapped_ratio = 100 - (wbs->nr_mapped * 100) / total_pages;
+ unmapped_ratio = 100 - ((global_page_state(NR_FILE_MAPPED) +
+ global_page_state(NR_ANON_PAGES)) * 100) /
+ vm_total_pages;
dirty_ratio = vm_dirty_ratio;
if (dirty_ratio > unmapped_ratio / 2)
*/
static void balance_dirty_pages(struct address_space *mapping)
{
- struct writeback_state wbs;
long nr_reclaimable;
long background_thresh;
long dirty_thresh;
.range_cyclic = 1,
};
- get_dirty_limits(&wbs, &background_thresh,
- &dirty_thresh, mapping);
- nr_reclaimable = wbs.nr_dirty + wbs.nr_unstable;
- if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
- break;
+ get_dirty_limits(&background_thresh, &dirty_thresh, mapping);
+ nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS);
+ if (nr_reclaimable + global_page_state(NR_WRITEBACK) <=
+ dirty_thresh)
+ break;
if (!dirty_exceeded)
dirty_exceeded = 1;
*/
if (nr_reclaimable) {
writeback_inodes(&wbc);
- get_dirty_limits(&wbs, &background_thresh,
- &dirty_thresh, mapping);
- nr_reclaimable = wbs.nr_dirty + wbs.nr_unstable;
- if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
- break;
+ get_dirty_limits(&background_thresh,
+ &dirty_thresh, mapping);
+ nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS);
+ if (nr_reclaimable +
+ global_page_state(NR_WRITEBACK)
+ <= dirty_thresh)
+ break;
pages_written += write_chunk - wbc.nr_to_write;
if (pages_written >= write_chunk)
break; /* We've done our duty */
blk_congestion_wait(WRITE, HZ/10);
}
- if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh && dirty_exceeded)
- dirty_exceeded = 0;
+ if (nr_reclaimable + global_page_state(NR_WRITEBACK)
+ <= dirty_thresh && dirty_exceeded)
+ dirty_exceeded = 0;
if (writeback_in_progress(bdi))
return; /* pdflush is already working this queue */
pdflush_operation(background_writeout, 0);
}
+void set_page_dirty_balance(struct page *page)
+{
+ if (set_page_dirty(page)) {
+ struct address_space *mapping = page_mapping(page);
+
+ if (mapping)
+ balance_dirty_pages_ratelimited(mapping);
+ }
+}
+
/**
* balance_dirty_pages_ratelimited_nr - balance dirty memory state
* @mapping: address_space which was dirtied
void throttle_vm_writeout(void)
{
- struct writeback_state wbs;
long background_thresh;
long dirty_thresh;
for ( ; ; ) {
- get_dirty_limits(&wbs, &background_thresh, &dirty_thresh, NULL);
+ get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
/*
* Boost the allowable dirty threshold a bit for page
*/
dirty_thresh += dirty_thresh / 10; /* wheeee... */
- if (wbs.nr_unstable + wbs.nr_writeback <= dirty_thresh)
- break;
+ if (global_page_state(NR_UNSTABLE_NFS) +
+ global_page_state(NR_WRITEBACK) <= dirty_thresh)
+ break;
blk_congestion_wait(WRITE, HZ/10);
}
}
};
for ( ; ; ) {
- struct writeback_state wbs;
long background_thresh;
long dirty_thresh;
- get_dirty_limits(&wbs, &background_thresh, &dirty_thresh, NULL);
- if (wbs.nr_dirty + wbs.nr_unstable < background_thresh
+ get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
+ if (global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS) < background_thresh
&& min_pages <= 0)
break;
wbc.encountered_congestion = 0;
*/
int wakeup_pdflush(long nr_pages)
{
- if (nr_pages == 0) {
- struct writeback_state wbs;
-
- get_writeback_state(&wbs);
- nr_pages = wbs.nr_dirty + wbs.nr_unstable;
- }
+ if (nr_pages == 0)
+ nr_pages = global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS);
return pdflush_operation(background_writeout, nr_pages);
}
unsigned long start_jif;
unsigned long next_jif;
long nr_to_write;
- struct writeback_state wbs;
struct writeback_control wbc = {
.bdi = NULL,
.sync_mode = WB_SYNC_NONE,
sync_supers();
- get_writeback_state(&wbs);
oldest_jif = jiffies - dirty_expire_interval;
start_jif = jiffies;
next_jif = start_jif + dirty_writeback_interval;
- nr_to_write = wbs.nr_dirty + wbs.nr_unstable +
+ nr_to_write = global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS) +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
while (nr_to_write > 0) {
wbc.encountered_congestion = 0;
* 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)
static int __cpuinit
ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
{
- set_ratelimit();
+ writeback_set_ratelimit();
return 0;
}
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;
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;
return 0;
wbc->for_writepages = 1;
if (mapping->a_ops->writepages)
- ret = mapping->a_ops->writepages(mapping, wbc);
+ ret = mapping->a_ops->writepages(mapping, wbc);
else
ret = generic_writepages(mapping, wbc);
wbc->for_writepages = 0;
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
if (mapping_cap_account_dirty(mapping))
- inc_page_state(nr_dirty);
+ __inc_zone_page_state(page,
+ NR_FILE_DIRTY);
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
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))
{
int ret;
- lock_page(page);
+ lock_page_nosync(page);
ret = set_page_dirty(page);
unlock_page(page);
return ret;
page_index(page),
PAGECACHE_TAG_DIRTY);
write_unlock_irqrestore(&mapping->tree_lock, flags);
- if (mapping_cap_account_dirty(mapping))
- dec_page_state(nr_dirty);
+ /*
+ * We can continue to use `mapping' here because the
+ * page is locked, which pins the address_space
+ */
+ if (mapping_cap_account_dirty(mapping)) {
+ page_mkclean(page);
+ dec_zone_page_state(page, NR_FILE_DIRTY);
+ }
return 1;
}
write_unlock_irqrestore(&mapping->tree_lock, flags);
if (mapping) {
if (TestClearPageDirty(page)) {
- if (mapping_cap_account_dirty(mapping))
- dec_page_state(nr_dirty);
+ if (mapping_cap_account_dirty(mapping)) {
+ page_mkclean(page);
+ dec_zone_page_state(page, NR_FILE_DIRTY);
+ }
return 1;
}
return 0;
}
EXPORT_SYMBOL(test_set_page_writeback);
+/*
+ * Wakes up tasks that are being throttled due to writeback congestion
+ */
+void writeback_congestion_end(void)
+{
+ blk_congestion_end(WRITE);
+}
+EXPORT_SYMBOL(writeback_congestion_end);
+
/*
* Return true if any of the pages in the mapping are marged with the
* passed tag.
git.samba.org / sfrench / cifs-2.6.git / blobdiff