This patch series aims to eliminate task hangs in mem_cgroup_css_free() caused by calling wb_wait_for_completion(). This is because there may be a large number of writeback tasks in the foreign memcg, involving millions of pages, and the situation is exacerbated by WBT rate limiting—potentially leading to task hangs lasting several hours. Patch 1 is preparatory work and involves no functional changes. Patch 2 implements the automatic release of wb_completion. Patch 3 removes wb_wait_for_completion() from mem_cgroup_css_free(). Julian Sun (3): writeback: Rename wb_writeback_work->auto_free to free_work. writeback: Add wb_writeback_work->free_done memcg: Don't wait writeback completion when release memcg. fs/fs-writeback.c | 22 ++++++++++++++-------- include/linux/backing-dev-defs.h | 6 ++++++ include/linux/memcontrol.h | 2 +- mm/memcontrol.c | 29 ++++++++++++++++++++--------- 4 files changed, 41 insertions(+), 18 deletions(-) -- 2.20.1
