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 715881F4CAB for ; Wed, 14 May 2025 05:59:02 +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=1747202342; cv=none; b=T++4tELjuGL0xdDHgiAYHga+64jBRVB/4om/GRjCJURM3ktOjRa3Zxq2y1XnxPKPyat1I5PFSZ8fmtkrfZMC2d9wBlmcQ94EaQ5ohaZwkfAxBOq5YgmRZ/QqvEyE4S05Gog9mock5Uq9tMd+mER0fDx5eHatZ8bFJgMWZQruBPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747202342; c=relaxed/simple; bh=Ebp9tfHiJR8CsjjQJcc+UMTIQtimua9Rn4/uH74yao0=; h=Date:To:From:Subject:Message-Id; b=MYsfPqJxSK4BkQuqSOx0wZXBzgzCmPZSWZNu4Xv2PJoq/NTzYfSRS01XE86SoKgPR3Bd62cs6ioLJOtIn7EYNVnMU0M1U3lRTQ8VZA4d4JBVu0tnoVGWOhzj+LGyOrU5fIRVfW9Zha511WBPm/Sy2IcwGggGL30MHWzoHPGScfE= 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=KWHkDQHP; 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="KWHkDQHP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5085C4CEE9; Wed, 14 May 2025 05:59:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1747202341; bh=Ebp9tfHiJR8CsjjQJcc+UMTIQtimua9Rn4/uH74yao0=; h=Date:To:From:Subject:From; b=KWHkDQHPULysCOVWYcZzNTpEfdPCHZ7VX/4f7AnysfoI3IBw374XtKPjzP9eflVF1 JXCx1McNdAH10Wa8WiFUjVVzwtKpI/Gq/DR1VwWrRxixXXSzipeuHWpXDSOJsvSclj zw/WXA3Y/I5Lr7iOvsUlvFlM2hjzEsEHVj8FFXNw= Date: Tue, 13 May 2025 22:59:01 -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: + memcg-objcg-stock-trylock-without-irq-disabling.patch added to mm-new branch Message-Id: <20250514055901.D5085C4CEE9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: memcg: objcg stock trylock without irq disabling has been added to the -mm mm-new branch. Its filename is memcg-objcg-stock-trylock-without-irq-disabling.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcg-objcg-stock-trylock-without-irq-disabling.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Shakeel Butt Subject: memcg: objcg stock trylock without irq disabling Date: Tue, 13 May 2025 22:08:13 -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/20250514050813.2526843-8-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-memcg_rstat_updated-re-entrant-safe-against-irqs.patch memcg-move-preempt-disable-to-callers-of-memcg_rstat_updated.patch memcg-make-mod_memcg_state-re-entrant-safe-against-irqs.patch memcg-make-count_memcg_events-re-entrant-safe-against-irqs.patch memcg-make-__mod_memcg_lruvec_state-re-entrant-safe-against-irqs.patch memcg-no-stock-lock-for-cpu-hot-unplug.patch memcg-objcg-stock-trylock-without-irq-disabling.patch