From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: [PATCH] mm: memcontrol: switch to rstat fix Date: Mon, 15 Mar 2021 19:41:00 -0400 Message-ID: <20210315234100.64307-1-hannes@cmpxchg.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=sHh364PFI7gr7Rg7wpaysNQPtI9BiNpDxSsKea0W7pA=; b=KbheRMtg2robQTyXPOEUrlWiONJ6e2isDPkgv9TYBs4HWXHrRdzR9F4j8VM+dTeX2M eabV8ybFsCDihGBWhwgMPDDTOX737BCr06IpzJThWzsqHtEJiT5yZZq3Z89KjreYoS2W 9GMEiDZw38HOxAu7Z1TuHEAcU6cUTzw/i3xPEKKtM4aJJtASYaaboQmNpTbWdtH+uOIs tAPWz2umjmR8R0K+EHsBDPmG35CNquRmgrNIM+onWovfmkuPW6eYCeH4T0Bg0KGQ1Jbo 2m7pNiKU76I12k+7IUBC77cbwWHyrwEwwo1g1QPp8LoL/FS4EHStaALOmG1cd3x7bIUn ms7Q== List-ID: Content-Type: text/plain; charset="us-ascii" To: Andrew Morton Cc: Michal Hocko , Roman Gushchin , Shakeel Butt , Tejun Heo , =?UTF-8?q?Michal=20Koutn=C3=BD?= , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Fix a sleep in atomic section problem: wb_writeback() takes a spinlock and calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular rstat flushing function called from in there does lockbreaking and may sleep. Switch to the atomic variant, cgroup_rstat_irqsafe(). To be consistent with other memcg flush calls, but without adding another memcg wrapper, inline and drop memcg_flush_vmstats() instead. Signed-off-by: Johannes Weiner --- mm/memcontrol.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f7fb12d3c2fc..9091913ec877 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -757,11 +757,6 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) return mz; } -static void memcg_flush_vmstats(struct mem_cgroup *memcg) -{ - cgroup_rstat_flush(memcg->css.cgroup); -} - /** * __mod_memcg_state - update cgroup memory statistics * @memcg: the memory cgroup @@ -1572,7 +1567,7 @@ static char *memory_stat_format(struct mem_cgroup *memcg) * * Current memory state: */ - memcg_flush_vmstats(memcg); + cgroup_rstat_flush(memcg->css.cgroup); for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { u64 size; @@ -3523,7 +3518,7 @@ static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) unsigned long val; if (mem_cgroup_is_root(memcg)) { - memcg_flush_vmstats(memcg); + cgroup_rstat_flush(memcg->css.cgroup); val = memcg_page_state(memcg, NR_FILE_PAGES) + memcg_page_state(memcg, NR_ANON_MAPPED); if (swap) @@ -3925,7 +3920,7 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v) int nid; struct mem_cgroup *memcg = mem_cgroup_from_seq(m); - memcg_flush_vmstats(memcg); + cgroup_rstat_flush(memcg->css.cgroup); for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { seq_printf(m, "%s=%lu", stat->name, @@ -3997,7 +3992,7 @@ static int memcg_stat_show(struct seq_file *m, void *v) BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats)); - memcg_flush_vmstats(memcg); + cgroup_rstat_flush(memcg->css.cgroup); for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; @@ -4500,7 +4495,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); struct mem_cgroup *parent; - memcg_flush_vmstats(memcg); + cgroup_rstat_flush_irqsafe(memcg->css.cgroup); *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY); *pwriteback = memcg_page_state(memcg, NR_WRITEBACK); -- 2.30.1