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From: Stefan Roesch <[email protected]>
To: <[email protected]>, <[email protected]>,
	<[email protected]>, <[email protected]>,
	<[email protected]>
Cc: <[email protected]>, <[email protected]>, <[email protected]>
Subject: [RFC PATCH v2 13/16] mm: add balance_dirty_pages_ratelimited_flags() function
Date: Mon, 16 May 2022 09:47:15 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

This adds the function balance_dirty_pages_ratelimited_flags(). It adds
the parameter is_async to balance_dirty_pages_ratelimited(). In case
this is an async write, it will call _balance_diirty_pages() to
determine if write throttling needs to be enabled. If write throttling
is enabled, it retuns -EAGAIN, so the write request can be punted to
the io-uring worker.

The new function is changed to return the sleep time, so callers can
observe if the write has been punted.

For non-async writes the current behavior is maintained.

Signed-off-by: Stefan Roesch <[email protected]>
---
 include/linux/writeback.h |  1 +
 mm/page-writeback.c       | 48 ++++++++++++++++++++++++++-------------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index fec248ab1fec..d589804bb3be 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -373,6 +373,7 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
 
 void wb_update_bandwidth(struct bdi_writeback *wb);
 void balance_dirty_pages_ratelimited(struct address_space *mapping);
+int  balance_dirty_pages_ratelimited_flags(struct address_space *mapping, bool is_async);
 bool wb_over_bg_thresh(struct bdi_writeback *wb);
 
 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index cbb74c0666c6..78f1326f3f20 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1877,28 +1877,17 @@ static DEFINE_PER_CPU(int, bdp_ratelimits);
  */
 DEFINE_PER_CPU(int, dirty_throttle_leaks) = 0;
 
-/**
- * balance_dirty_pages_ratelimited - balance dirty memory state
- * @mapping: address_space which was dirtied
- *
- * Processes which are dirtying memory should call in here once for each page
- * which was newly dirtied.  The function will periodically check the system's
- * dirty state and will initiate writeback if needed.
- *
- * Once we're over the dirty memory limit we decrease the ratelimiting
- * by a lot, to prevent individual processes from overshooting the limit
- * by (ratelimit_pages) each.
- */
-void balance_dirty_pages_ratelimited(struct address_space *mapping)
+int balance_dirty_pages_ratelimited_flags(struct address_space *mapping, bool is_async)
 {
 	struct inode *inode = mapping->host;
 	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	struct bdi_writeback *wb = NULL;
 	int ratelimit;
+	int ret = 0;
 	int *p;
 
 	if (!(bdi->capabilities & BDI_CAP_WRITEBACK))
-		return;
+		return ret;
 
 	if (inode_cgwb_enabled(inode))
 		wb = wb_get_create_current(bdi, GFP_KERNEL);
@@ -1937,10 +1926,37 @@ void balance_dirty_pages_ratelimited(struct address_space *mapping)
 	}
 	preempt_enable();
 
-	if (unlikely(current->nr_dirtied >= ratelimit))
-		balance_dirty_pages(wb, current->nr_dirtied);
+	if (unlikely(current->nr_dirtied >= ratelimit)) {
+		if (is_async) {
+			struct bdp_ctx ctx = { BDP_CTX_INIT(ctx, wb) };
+
+			ret = _balance_dirty_pages(wb, current->nr_dirtied, &ctx);
+			if (ret)
+				ret = -EAGAIN;
+		} else {
+			balance_dirty_pages(wb, current->nr_dirtied);
+		}
+	}
 
 	wb_put(wb);
+	return ret;
+}
+
+/**
+ * balance_dirty_pages_ratelimited - balance dirty memory state
+ * @mapping: address_space which was dirtied
+ *
+ * Processes which are dirtying memory should call in here once for each page
+ * which was newly dirtied.  The function will periodically check the system's
+ * dirty state and will initiate writeback if needed.
+ *
+ * Once we're over the dirty memory limit we decrease the ratelimiting
+ * by a lot, to prevent individual processes from overshooting the limit
+ * by (ratelimit_pages) each.
+ */
+void balance_dirty_pages_ratelimited(struct address_space *mapping)
+{
+	balance_dirty_pages_ratelimited_flags(mapping, false);
 }
 EXPORT_SYMBOL(balance_dirty_pages_ratelimited);
 
-- 
2.30.2


  parent reply	other threads:[~2022-05-16 16:49 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-16 16:47 [RFC PATCH v2 00/16] io-uring/xfs: support async buffered writes Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 01/16] block: add check for async buffered writes to generic_write_checks Stefan Roesch
2022-05-16 23:43   ` Matthew Wilcox
2022-05-18 23:20     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 02/16] iomap: add iomap_page_create_gfp to allocate iomap_pages Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 03/16] iomap: use iomap_page_create_gfp() in __iomap_write_begin Stefan Roesch
2022-05-16 23:58   ` Matthew Wilcox
2022-05-18 23:21     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 04/16] iomap: add async buffered write support Stefan Roesch
2022-05-17 11:14   ` Jan Kara
2022-05-18 23:19     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 05/16] xfs: add iomap " Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 06/16] fs: split off need_remove_file_privs() do_remove_file_privs() Stefan Roesch
2022-05-17 13:18   ` Christian Brauner
2022-05-18 23:25     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 07/16] fs: split off need_file_update_time and do_file_update_time Stefan Roesch
2022-05-17 11:20   ` Jan Kara
2022-05-18 23:21     ` Stefan Roesch
2022-05-17 13:40   ` Christian Brauner
2022-05-18 23:28     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 08/16] fs: add pending file update time flag Stefan Roesch
2022-05-17 11:28   ` Jan Kara
2022-05-17 13:48     ` Christian Brauner
2022-05-18 23:23     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 09/16] xfs: enable async write file modification handling Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 10/16] xfs: add async buffered write support Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 11/16] io_uring: add support for async buffered writes Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 12/16] mm: factor out _balance_dirty_pages() from balance_dirty_pages() Stefan Roesch
2022-05-18 11:07   ` Jan Kara
2022-05-18 23:31     ` Stefan Roesch
2022-05-16 16:47 ` Stefan Roesch [this message]
2022-05-17 20:12   ` [RFC PATCH v2 13/16] mm: add balance_dirty_pages_ratelimited_flags() function Jan Kara
2022-05-18 23:29     ` Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 14/16] iomap: use balance_dirty_pages_ratelimited_flags in iomap_write_iter Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 15/16] io_uring: add tracepoint for short writes Stefan Roesch
2022-05-16 16:47 ` [RFC PATCH v2 16/16] xfs: enable async buffered write support Stefan Roesch

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