From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.126.com (m16.mail.126.com [220.197.31.8]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 808661DFE23 for ; Tue, 18 Mar 2025 08:07:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.8 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742285260; cv=none; b=VslJLm7ABba6lyq1x72GeivorLiv3XcorPOL6DFRGzs+jjxIxNVLTX+Ug35ojWmAFW3YSO/YggrvCFWLUJ5qDRbJpVLPRJDCHlHdlvRvQi/nVfHiNlTBnSOSpefDiSSHzYEgS/5KP3MFMcUxq7TxgDF1JzPb4amrG6okHeUgXy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742285260; c=relaxed/simple; bh=gj8ztjx4DDXc8wmr8TSvDP3057YD+rf2ndJtlNgm8o0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aouCmupPoHPCmQIlc2Ds/WxRnS+qWixtjCFn+5yhCT5uilx7RPKYvh4cFFN3WRwAD4l+7wgLLnSZBzTRdYwqMHbS4prqEF8S1/uYKcTRfDD29EmVAp3GLuLWgaFkeDIbaii2oO8VplFNJAv4D7yEOc9c/0AyL4NIDWNjoU1PK9U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com; spf=pass smtp.mailfrom=126.com; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b=mJ4/1SIg; arc=none smtp.client-ip=220.197.31.8 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=126.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b="mJ4/1SIg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=Message-ID:Date:MIME-Version:Subject:From: Content-Type; bh=xAv74FX3DoajPloCyOTTZZeRXTUHncsx5Pnyk67rO28=; b=mJ4/1SIg/aUMGV0gn9/9PCKruF2BIM3Yg1wS5VVSX04zaBkBte77Evc1xa0RIF kvz6MEj1iofetvtwEkoIELZIIrHP2OaneYo4lOjN4f1q+FoNTMt5QpmtNcKP3dvi CsRCBeWIXuVkkyMPkP7iTGZLxd3z9o10GJL28BxyHBtxU= Received: from [172.19.20.199] (unknown []) by gzsmtp3 (Coremail) with SMTP id PikvCgD3jrsGH9lnEPZYCA--.20701S2; Tue, 18 Mar 2025 15:21:43 +0800 (CST) Message-ID: <09057869-eb32-45dd-a7a1-9b7e1850eb11@126.com> Date: Tue, 18 Mar 2025 15:21:42 +0800 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 V2] mm/cma: using per-CMA locks to improve concurrent allocation performance To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, 21cnbao@gmail.com, david@redhat.com, baolin.wang@linux.alibaba.com, aisheng.dong@nxp.com, liuzixing@hygon.cn References: <1739152566-744-1-git-send-email-yangge1116@126.com> <20250317204325.99b45373023ad2f901c1152e@linux-foundation.org> From: Ge Yang In-Reply-To: <20250317204325.99b45373023ad2f901c1152e@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:PikvCgD3jrsGH9lnEPZYCA--.20701S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxKFyxAF1fGrWxtFWxAF4Utwb_yoWxJFy5pF W8GFyDCr98Xry7Aw42k34DuF9a9ws7WFW7KFyjva4xZFnxCr90grs5tFy5u3y8urZrWFy0 vryjqasrZw1UZ3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jYGQhUUUUU= X-CM-SenderInfo: 51dqwwjhrrila6rslhhfrp/1tbiIh0UG2fZFYW67QAAsJ 在 2025/3/18 11:43, Andrew Morton 写道: > On Mon, 10 Feb 2025 09:56:06 +0800 yangge1116@126.com wrote: > >> From: yangge >> >> For different CMAs, concurrent allocation of CMA memory ideally should not >> require synchronization using locks. Currently, a global cma_mutex lock is >> employed to synchronize all CMA allocations, which can impact the >> performance of concurrent allocations across different CMAs. >> >> To test the performance impact, follow these steps: >> 1. Boot the kernel with the command line argument hugetlb_cma=30G to >> allocate a 30GB CMA area specifically for huge page allocations. (note: >> on my machine, which has 3 nodes, each node is initialized with 10G of >> CMA) >> 2. Use the dd command with parameters if=/dev/zero of=/dev/shm/file bs=1G >> count=30 to fully utilize the CMA area by writing zeroes to a file in >> /dev/shm. >> 3. Open three terminals and execute the following commands simultaneously: >> (Note: Each of these commands attempts to allocate 10GB [2621440 * 4KB >> pages] of CMA memory.) >> On Terminal 1: time echo 2621440 > /sys/kernel/debug/cma/hugetlb1/alloc >> On Terminal 2: time echo 2621440 > /sys/kernel/debug/cma/hugetlb2/alloc >> On Terminal 3: time echo 2621440 > /sys/kernel/debug/cma/hugetlb3/alloc >> >> We attempt to allocate pages through the CMA debug interface and use the >> time command to measure the duration of each allocation. >> Performance comparison: >> Without this patch With this patch >> Terminal1 ~7s ~7s >> Terminal2 ~14s ~8s >> Terminal3 ~21s ~7s >> >> To slove problem above, we could use per-CMA locks to improve concurrent >> allocation performance. This would allow each CMA to be managed >> independently, reducing the need for a global lock and thus improving >> scalability and performance. > > This patch was in and out of mm-unstable for a while, as Frank's series > "hugetlb/CMA improvements for large systems" was being added and > dropped. > > Consequently it hasn't received any testing for a while. > > Below is the version which I've now re-added to mm-unstable. Can > you please check this and retest it? Based on the latest mm-unstable code, after applying the patch and conducting tests, it works normally. Thanks. > > Thanks. > > From: Ge Yang > Subject: mm/cma: using per-CMA locks to improve concurrent allocation performance > Date: Mon, 10 Feb 2025 09:56:06 +0800 > > For different CMAs, concurrent allocation of CMA memory ideally should not > require synchronization using locks. Currently, a global cma_mutex lock > is employed to synchronize all CMA allocations, which can impact the > performance of concurrent allocations across different CMAs. > > To test the performance impact, follow these steps: > 1. Boot the kernel with the command line argument hugetlb_cma=30G to > allocate a 30GB CMA area specifically for huge page allocations. (note: > on my machine, which has 3 nodes, each node is initialized with 10G of > CMA) > 2. Use the dd command with parameters if=/dev/zero of=/dev/shm/file bs=1G > count=30 to fully utilize the CMA area by writing zeroes to a file in > /dev/shm. > 3. Open three terminals and execute the following commands simultaneously: > (Note: Each of these commands attempts to allocate 10GB [2621440 * 4KB > pages] of CMA memory.) > On Terminal 1: time echo 2621440 > /sys/kernel/debug/cma/hugetlb1/alloc > On Terminal 2: time echo 2621440 > /sys/kernel/debug/cma/hugetlb2/alloc > On Terminal 3: time echo 2621440 > /sys/kernel/debug/cma/hugetlb3/alloc > > We attempt to allocate pages through the CMA debug interface and use the > time command to measure the duration of each allocation. > Performance comparison: > Without this patch With this patch > Terminal1 ~7s ~7s > Terminal2 ~14s ~8s > Terminal3 ~21s ~7s > > To solve problem above, we could use per-CMA locks to improve concurrent > allocation performance. This would allow each CMA to be managed > independently, reducing the need for a global lock and thus improving > scalability and performance. > > Link: https://lkml.kernel.org/r/1739152566-744-1-git-send-email-yangge1116@126.com > Signed-off-by: Ge Yang > Reviewed-by: Barry Song > Acked-by: David Hildenbrand > Reviewed-by: Oscar Salvador > Cc: Aisheng Dong > Cc: Baolin Wang > Signed-off-by: Andrew Morton > --- > > mm/cma.c | 7 ++++--- > mm/cma.h | 1 + > 2 files changed, 5 insertions(+), 3 deletions(-) > > --- a/mm/cma.c~mm-cma-using-per-cma-locks-to-improve-concurrent-allocation-performance > +++ a/mm/cma.c > @@ -34,7 +34,6 @@ > > struct cma cma_areas[MAX_CMA_AREAS]; > unsigned int cma_area_count; > -static DEFINE_MUTEX(cma_mutex); > > static int __init __cma_declare_contiguous_nid(phys_addr_t base, > phys_addr_t size, phys_addr_t limit, > @@ -175,6 +174,8 @@ static void __init cma_activate_area(str > > spin_lock_init(&cma->lock); > > + mutex_init(&cma->alloc_mutex); > + > #ifdef CONFIG_CMA_DEBUGFS > INIT_HLIST_HEAD(&cma->mem_head); > spin_lock_init(&cma->mem_head_lock); > @@ -813,9 +814,9 @@ static int cma_range_alloc(struct cma *c > spin_unlock_irq(&cma->lock); > > pfn = cmr->base_pfn + (bitmap_no << cma->order_per_bit); > - mutex_lock(&cma_mutex); > + mutex_lock(&cma->alloc_mutex); > ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp); > - mutex_unlock(&cma_mutex); > + mutex_unlock(&cma->alloc_mutex); > if (ret == 0) { > page = pfn_to_page(pfn); > break; > --- a/mm/cma.h~mm-cma-using-per-cma-locks-to-improve-concurrent-allocation-performance > +++ a/mm/cma.h > @@ -39,6 +39,7 @@ struct cma { > unsigned long available_count; > unsigned int order_per_bit; /* Order of pages represented by one bit */ > spinlock_t lock; > + struct mutex alloc_mutex; > #ifdef CONFIG_CMA_DEBUGFS > struct hlist_head mem_head; > spinlock_t mem_head_lock; > _