From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1FADA2222C8 for ; Wed, 21 May 2025 16:57:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747846672; cv=none; b=Fd+euYydd3694M+yD550RMHbVW/uYXlsFY9trgaYpUyL5ufDzTOTnyGSOEdCr6vGd98DziJwDY0SObfGt7jmqQmcdyQQcrmQ/1hKVlMgQAGFIxCzkW1ONxzKC/HOwK3jyUxqC4Na8jDRpOjFaHOqEO8ZILA7mgYyD6OZR5eEqeI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747846672; c=relaxed/simple; bh=Q7uaMjNO/OnzFjanMJiBsHjyfAK6kMzUg2Pm6t20Ozk=; h=Date:To:From:Subject:Message-Id; b=JE3+QQAmJ5zJ2Q2JmFsqsy/HovWuKuSz2DpF/8XNIrTCxfMirPo+VSd97X0JOCn2YnxIUkplRW8JpuawttTJxJaTn5FXQs2fSftNO/gIyqDM6jH61i9HQ7mZTKWUwKhChY6YsFRNn13d6OsxW2lZ+3lqqlR8Dn7cCFJTEtMZ7HI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=jkthCH2X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="jkthCH2X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD201C4CEE7; Wed, 21 May 2025 16:57:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1747846672; bh=Q7uaMjNO/OnzFjanMJiBsHjyfAK6kMzUg2Pm6t20Ozk=; h=Date:To:From:Subject:From; b=jkthCH2Xgk/5Abuf/ua3Tq6G/ye9Nz3SvHeEhE+fE9yRgEbYdaA9d8Ltvw00mTFq7 dKM/Uhn1QqWbR4lCPTSh+S1YZOOsVQ9oP8pVpXkJJOMIGpDkwa3PMJFi2y/YvlhwYa pXa1kPx/6QA1gYSKPBBMZSR62oZ5hhnzeHciJj2g= Date: Wed, 21 May 2025 09:57:51 -0700 To: mm-commits@vger.kernel.org,vbabka@suse.cz,roman.gushchin@linux.dev,muchun.song@linux.dev,mhocko@kernel.org,hannes@cmpxchg.org,bigeasy@linutronix.de,ast@kernel.org,shakeel.butt@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] memcg-objcg-stock-trylock-without-irq-disabling.patch removed from -mm tree Message-Id: <20250521165751.DD201C4CEE7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: memcg: objcg stock trylock without irq disabling has been removed from the -mm tree. Its filename was memcg-objcg-stock-trylock-without-irq-disabling.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Shakeel Butt Subject: memcg: objcg stock trylock without irq disabling Date: Wed, 14 May 2025 11:41:58 -0700 There is no need to disable irqs to use objcg per-cpu stock, so let's just not do that but consume_obj_stock() and refill_obj_stock() will need to use trylock instead to avoid deadlock against irq. One consequence of this change is that the charge request from irq context may take slowpath more often but it should be rare. Link: https://lkml.kernel.org/r/20250514184158.3471331-8-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Acked-by: Vlastimil Babka Cc: Alexei Starovoitov Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Sebastian Andrzej Siewior Signed-off-by: Andrew Morton --- mm/memcontrol.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) --- a/mm/memcontrol.c~memcg-objcg-stock-trylock-without-irq-disabling +++ a/mm/memcontrol.c @@ -1882,18 +1882,17 @@ static void drain_local_memcg_stock(stru static void drain_local_obj_stock(struct work_struct *dummy) { struct obj_stock_pcp *stock; - unsigned long flags; if (WARN_ONCE(!in_task(), "drain in non-task context")) return; - local_lock_irqsave(&obj_stock.lock, flags); + local_lock(&obj_stock.lock); stock = this_cpu_ptr(&obj_stock); drain_obj_stock(stock); clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); - local_unlock_irqrestore(&obj_stock.lock, flags); + local_unlock(&obj_stock.lock); } static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) @@ -2876,10 +2875,10 @@ static bool consume_obj_stock(struct obj struct pglist_data *pgdat, enum node_stat_item idx) { struct obj_stock_pcp *stock; - unsigned long flags; bool ret = false; - local_lock_irqsave(&obj_stock.lock, flags); + if (!local_trylock(&obj_stock.lock)) + return ret; stock = this_cpu_ptr(&obj_stock); if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) { @@ -2890,7 +2889,7 @@ static bool consume_obj_stock(struct obj __account_obj_stock(objcg, stock, nr_bytes, pgdat, idx); } - local_unlock_irqrestore(&obj_stock.lock, flags); + local_unlock(&obj_stock.lock); return ret; } @@ -2979,10 +2978,16 @@ static void refill_obj_stock(struct obj_ enum node_stat_item idx) { struct obj_stock_pcp *stock; - unsigned long flags; unsigned int nr_pages = 0; - local_lock_irqsave(&obj_stock.lock, flags); + if (!local_trylock(&obj_stock.lock)) { + if (pgdat) + mod_objcg_mlstate(objcg, pgdat, idx, nr_bytes); + nr_pages = nr_bytes >> PAGE_SHIFT; + nr_bytes = nr_bytes & (PAGE_SIZE - 1); + atomic_add(nr_bytes, &objcg->nr_charged_bytes); + goto out; + } stock = this_cpu_ptr(&obj_stock); if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */ @@ -3004,8 +3009,8 @@ static void refill_obj_stock(struct obj_ stock->nr_bytes &= (PAGE_SIZE - 1); } - local_unlock_irqrestore(&obj_stock.lock, flags); - + local_unlock(&obj_stock.lock); +out: if (nr_pages) obj_cgroup_uncharge_pages(objcg, nr_pages); } _ Patches currently in -mm which might be from shakeel.butt@linux.dev are memcg-disable-kmem-charging-in-nmi-for-unsupported-arch.patch memcg-nmi-safe-memcg-stats-for-specific-archs.patch memcg-add-nmi-safe-update-for-memcg_kmem.patch memcg-nmi-safe-slab-stats-updates.patch memcg-make-memcg_rstat_updated-nmi-safe.patch