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authorYafang Shao <laoar.shao@gmail.com>2019-05-13 17:23:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 09:47:51 -0700
commit19343b5bdd16ad4ae6b845ef829f68b683c4dfb5 (patch)
treef6e36441b6b86ea3e4d499ebc35e3e7c9b6bd203 /mm/page-writeback.c
parent60b62ff7cc4217ac3de76535fa4c1510a798dbcb (diff)
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mm/page-writeback: introduce tracepoint for wait_on_page_writeback()
Recently there have been some hung tasks on our server due to wait_on_page_writeback(), and we want to know the details of this PG_writeback, i.e. this page is writing back to which device. But it is not so convenient to get the details. I think it would be better to introduce a tracepoint for diagnosing the writeback details. Link: http://lkml.kernel.org/r/1556274402-19018-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 9f61dfec6a1f..07656485c0e6 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2808,6 +2808,18 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
}
EXPORT_SYMBOL(__test_set_page_writeback);
+/*
+ * Wait for a page to complete writeback
+ */
+void wait_on_page_writeback(struct page *page)
+{
+ if (PageWriteback(page)) {
+ trace_wait_on_page_writeback(page, page_mapping(page));
+ wait_on_page_bit(page, PG_writeback);
+ }
+}
+EXPORT_SYMBOL_GPL(wait_on_page_writeback);
+
/**
* wait_for_stable_page() - wait for writeback to finish, if necessary.
* @page: The page to wait on.