From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BD06641A785 for ; Mon, 27 Jul 2026 17:14:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785172474; cv=none; b=jBxLyQVMOkN8a35bte2ElBkHnDSGMMfqgLLdtEZi0CRK3xfwATBeF1lHRexWr6QOhUMd3B0Quq2+BlEgo2b6ohzU0eB6JBaYDpTNo7o0wnJ3LLzVo450nxGhPRVRNYmA+NowW3sW/ZKGmJ4Awsz/745tikMi5WF+XTImzwvS4cQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785172474; c=relaxed/simple; bh=NceNdXss+IYFUd5WJwy+5Lycac/YVGli4KhPahl9bdU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aiYxHR7DW1sL1lNJlnfijmMKZ6WcI0WtQDz9frk7gmQyXmCoPYFHchSz0d2q1g/QIrFLqe06QD6AfAqa5yyGOHJ5OO6yJhq7KXQbgR24T8eNQzQG/6m++3/4JKFgu5yUO2Y1e2qBzSE0DPqX2NxgE/mj74LZMtBHV7bHqurhfow= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=OFjK3NWG; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="OFjK3NWG" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 185501682; Mon, 27 Jul 2026 10:14:28 -0700 (PDT) Received: from [10.2.212.23] (e121345-lin.cambridge.arm.com [10.2.212.23]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5BC0C3F763; Mon, 27 Jul 2026 10:14:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785172472; bh=NceNdXss+IYFUd5WJwy+5Lycac/YVGli4KhPahl9bdU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=OFjK3NWGki9leejOv6ZADA4vNcgV/vbFQJawCY8MMN3IZA0LOqghAYptHMftmJIPY Xv/gV3NGJksKCztx+Wg7KgLSeSADS4vwu2Wzz+b/zbMmWwBg8bduFvi3r+smOPFChq EYsNujXCIC/Sd+9pUtgc17mi/wIqC+Fsjoyb5kfY= Message-ID: <9ca5da69-50da-4583-97ae-986b90b5ef16@arm.com> Date: Mon, 27 Jul 2026 18:14:29 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] iommu/iova: Move CPU magazine init to first insert To: Logan Odell , joro@8bytes.org, will@kernel.org Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, mclapinski@google.com, skhawaja@google.com References: <20260727155720.2692587-1-loganodell@google.com> Content-Language: en-GB From: Robin Murphy In-Reply-To: <20260727155720.2692587-1-loganodell@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 27/07/2026 4:57 pm, Logan Odell wrote: > A large amount of memory may be allocated for these magazines on > machines with a lot of IOMMU groups and CPU cores. Not all may be used > as some devices may be unused or be bound to drivers that do not use the > DMA-API. Furthermore, some drivers may not use all levels or CPUs. > > Move the initialization of the loaded and prev magazines for each CPU on > the first attempt to try to insert a freed IOVA to them. > > Signed-off-by: Logan Odell > Signed-off-by: Michal Clapinski > --- > v2: only rebase > v3: Combine the initilaization logic with new magazine logic in __iova_rcache_insert LGTM, Reviewed-by: Robin Murphy Although as a process nit, since you've now taken back custody of the patch to make this update, technically you should either add your sign-off a second time after Michal's, or perhaps more neatly, give Michal a Co-developed-by and swap the sign-offs[1]. Thanks, Robin. [1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by > --- > > Change-Id: I987b6dfb2b1125d8da8618fff540f315b99bad13 > --- > drivers/iommu/iova.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 021daf6528de..82d52eb12e4c 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -621,6 +621,9 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad) > unsigned long flags; > int i; > > + if (!mag) > + return; > + > spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); > > for (i = 0 ; i < mag->size; ++i) { > @@ -739,12 +742,6 @@ int iova_domain_init_rcaches(struct iova_domain *iovad) > cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu); > > spin_lock_init(&cpu_rcache->lock); > - cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL); > - cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL); > - if (!cpu_rcache->loaded || !cpu_rcache->prev) { > - ret = -ENOMEM; > - goto out_err; > - } > } > } > > @@ -777,19 +774,23 @@ static bool __iova_rcache_insert(struct iova_domain *iovad, > cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches); > spin_lock_irqsave(&cpu_rcache->lock, flags); > > - if (!iova_magazine_full(cpu_rcache->loaded)) { > + if (cpu_rcache->loaded && !iova_magazine_full(cpu_rcache->loaded)) { > can_insert = true; > - } else if (!iova_magazine_full(cpu_rcache->prev)) { > + } else if (cpu_rcache->prev && !iova_magazine_full(cpu_rcache->prev)) { > swap(cpu_rcache->prev, cpu_rcache->loaded); > can_insert = true; > } else { > struct iova_magazine *new_mag = iova_magazine_alloc(GFP_ATOMIC); > > if (new_mag) { > - spin_lock(&rcache->lock); > - iova_depot_push(rcache, cpu_rcache->loaded); > - spin_unlock(&rcache->lock); > - schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY); > + if (cpu_rcache->loaded && !cpu_rcache->prev) { > + cpu_rcache->prev = cpu_rcache->loaded; > + } else if (cpu_rcache->loaded) { > + spin_lock(&rcache->lock); > + iova_depot_push(rcache, cpu_rcache->loaded); > + spin_unlock(&rcache->lock); > + schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY); > + } > > cpu_rcache->loaded = new_mag; > can_insert = true; > @@ -831,9 +832,9 @@ static unsigned long __iova_rcache_get(struct iova_rcache *rcache, > cpu_rcache = raw_cpu_ptr(rcache->cpu_rcaches); > spin_lock_irqsave(&cpu_rcache->lock, flags); > > - if (!iova_magazine_empty(cpu_rcache->loaded)) { > + if (cpu_rcache->loaded && !iova_magazine_empty(cpu_rcache->loaded)) { > has_pfn = true; > - } else if (!iova_magazine_empty(cpu_rcache->prev)) { > + } else if (cpu_rcache->prev && !iova_magazine_empty(cpu_rcache->prev)) { > swap(cpu_rcache->prev, cpu_rcache->loaded); > has_pfn = true; > } else {