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-rw-r--r--fs/ext4/ext4.h1
-rw-r--r--fs/ext4/inode.c105
-rw-r--r--fs/ext4/super.c3
-rw-r--r--include/trace/events/ext4.h14
4 files changed, 107 insertions, 16 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e227eea..a58438e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -942,6 +942,7 @@ struct ext4_sb_info {
unsigned int s_mb_stats;
unsigned int s_mb_order2_reqs;
unsigned int s_mb_group_prealloc;
+ unsigned int s_max_writeback_mb_bump;
/* where last allocation was done - for stream allocation */
unsigned long s_mb_last_group;
unsigned long s_mb_last_start;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5fb72a9..20e2d70 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1145,6 +1145,64 @@ static int check_block_validity(struct inode *inode, const char *msg,
}
/*
+ * Return the number of dirty pages in the given inode starting at
+ * page frame idx.
+ */
+static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
+ unsigned int max_pages)
+{
+ struct address_space *mapping = inode->i_mapping;
+ pgoff_t index;
+ struct pagevec pvec;
+ pgoff_t num = 0;
+ int i, nr_pages, done = 0;
+
+ if (max_pages == 0)
+ return 0;
+ pagevec_init(&pvec, 0);
+ while (!done) {
+ index = idx;
+ nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ (pgoff_t)PAGEVEC_SIZE);
+ if (nr_pages == 0)
+ break;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+ struct buffer_head *bh, *head;
+
+ lock_page(page);
+ if (unlikely(page->mapping != mapping) ||
+ !PageDirty(page) ||
+ PageWriteback(page) ||
+ page->index != idx) {
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+ head = page_buffers(page);
+ bh = head;
+ do {
+ if (!buffer_delay(bh) &&
+ !buffer_unwritten(bh)) {
+ done = 1;
+ break;
+ }
+ } while ((bh = bh->b_this_page) != head);
+ unlock_page(page);
+ if (done)
+ break;
+ idx++;
+ num++;
+ if (num >= max_pages)
+ break;
+ }
+ pagevec_release(&pvec);
+ }
+ return num;
+}
+
+/*
* The ext4_get_blocks() function tries to look up the requested blocks,
* and returns if the blocks are already mapped.
*
@@ -2743,8 +2801,10 @@ static int ext4_da_writepages(struct address_space *mapping,
int no_nrwrite_index_update;
int pages_written = 0;
long pages_skipped;
+ unsigned int max_pages;
int range_cyclic, cycled = 1, io_done = 0;
- int needed_blocks, ret = 0, nr_to_writebump = 0;
+ int needed_blocks, ret = 0;
+ long desired_nr_to_write, nr_to_writebump = 0;
loff_t range_start = wbc->range_start;
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
@@ -2771,16 +2831,6 @@ static int ext4_da_writepages(struct address_space *mapping,
if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
return -EROFS;
- /*
- * Make sure nr_to_write is >= sbi->s_mb_stream_request
- * This make sure small files blocks are allocated in
- * single attempt. This ensure that small files
- * get less fragmented.
- */
- if (wbc->nr_to_write < sbi->s_mb_stream_request) {
- nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
- wbc->nr_to_write = sbi->s_mb_stream_request;
- }
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
@@ -2795,6 +2845,36 @@ static int ext4_da_writepages(struct address_space *mapping,
} else
index = wbc->range_start >> PAGE_CACHE_SHIFT;
+ /*
+ * This works around two forms of stupidity. The first is in
+ * the writeback code, which caps the maximum number of pages
+ * written to be 1024 pages. This is wrong on multiple
+ * levels; different architectues have a different page size,
+ * which changes the maximum amount of data which gets
+ * written. Secondly, 4 megabytes is way too small. XFS
+ * forces this value to be 16 megabytes by multiplying
+ * nr_to_write parameter by four, and then relies on its
+ * allocator to allocate larger extents to make them
+ * contiguous. Unfortunately this brings us to the second
+ * stupidity, which is that ext4's mballoc code only allocates
+ * at most 2048 blocks. So we force contiguous writes up to
+ * the number of dirty blocks in the inode, or
+ * sbi->max_writeback_mb_bump whichever is smaller.
+ */
+ max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
+ if (!range_cyclic && range_whole)
+ desired_nr_to_write = wbc->nr_to_write * 8;
+ else
+ desired_nr_to_write = ext4_num_dirty_pages(inode, index,
+ max_pages);
+ if (desired_nr_to_write > max_pages)
+ desired_nr_to_write = max_pages;
+
+ if (wbc->nr_to_write < desired_nr_to_write) {
+ nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
+ wbc->nr_to_write = desired_nr_to_write;
+ }
+
mpd.wbc = wbc;
mpd.inode = mapping->host;
@@ -2914,7 +2994,8 @@ retry:
out_writepages:
if (!no_nrwrite_index_update)
wbc->no_nrwrite_index_update = 0;
- wbc->nr_to_write -= nr_to_writebump;
+ if (wbc->nr_to_write > nr_to_writebump)
+ wbc->nr_to_write -= nr_to_writebump;
wbc->range_start = range_start;
trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
return ret;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index df539ba..1681773 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2197,6 +2197,7 @@ EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
+EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
static struct attribute *ext4_attrs[] = {
ATTR_LIST(delayed_allocation_blocks),
@@ -2210,6 +2211,7 @@ static struct attribute *ext4_attrs[] = {
ATTR_LIST(mb_order2_req),
ATTR_LIST(mb_stream_req),
ATTR_LIST(mb_group_prealloc),
+ ATTR_LIST(max_writeback_mb_bump),
NULL,
};
@@ -2679,6 +2681,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
}
sbi->s_stripe = ext4_get_stripe_size(sbi);
+ sbi->s_max_writeback_mb_bump = 128;
/*
* set up enough so that it can read an inode
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index c1bd8f1..7c6bbb7 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -236,6 +236,7 @@ TRACE_EVENT(ext4_da_writepages,
__field( char, for_kupdate )
__field( char, for_reclaim )
__field( char, range_cyclic )
+ __field( pgoff_t, writeback_index )
),
TP_fast_assign(
@@ -249,15 +250,17 @@ TRACE_EVENT(ext4_da_writepages,
__entry->for_kupdate = wbc->for_kupdate;
__entry->for_reclaim = wbc->for_reclaim;
__entry->range_cyclic = wbc->range_cyclic;
+ __entry->writeback_index = inode->i_mapping->writeback_index;
),
- TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d range_cyclic %d",
+ TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d range_cyclic %d writeback_index %lu",
jbd2_dev_to_name(__entry->dev),
(unsigned long) __entry->ino, __entry->nr_to_write,
__entry->pages_skipped, __entry->range_start,
__entry->range_end, __entry->nonblocking,
__entry->for_kupdate, __entry->for_reclaim,
- __entry->range_cyclic)
+ __entry->range_cyclic,
+ (unsigned long) __entry->writeback_index)
);
TRACE_EVENT(ext4_da_write_pages,
@@ -309,6 +312,7 @@ TRACE_EVENT(ext4_da_writepages_result,
__field( char, encountered_congestion )
__field( char, more_io )
__field( char, no_nrwrite_index_update )
+ __field( pgoff_t, writeback_index )
),
TP_fast_assign(
@@ -320,14 +324,16 @@ TRACE_EVENT(ext4_da_writepages_result,
__entry->encountered_congestion = wbc->encountered_congestion;
__entry->more_io = wbc->more_io;
__entry->no_nrwrite_index_update = wbc->no_nrwrite_index_update;
+ __entry->writeback_index = inode->i_mapping->writeback_index;
),
- TP_printk("dev %s ino %lu ret %d pages_written %d pages_skipped %ld congestion %d more_io %d no_nrwrite_index_update %d",
+ TP_printk("dev %s ino %lu ret %d pages_written %d pages_skipped %ld congestion %d more_io %d no_nrwrite_index_update %d writeback_index %lu",
jbd2_dev_to_name(__entry->dev),
(unsigned long) __entry->ino, __entry->ret,
__entry->pages_written, __entry->pages_skipped,
__entry->encountered_congestion, __entry->more_io,
- __entry->no_nrwrite_index_update)
+ __entry->no_nrwrite_index_update,
+ (unsigned long) __entry->writeback_index)
);
TRACE_EVENT(ext4_da_write_begin,
generated by cgit v1.1 at 2024-11-17 02:06:31 +0000