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X-CSE-ConnectionGUID: YLOwbT1BRDCJJd0Rqbdplw== X-CSE-MsgGUID: bVyZUjTqQaqMAPrTYt0HXw== X-IronPort-AV: E=McAfee;i="6700,10204,11182"; a="23616293" X-IronPort-AV: E=Sophos;i="6.10,194,1719903600"; d="scan'208";a="23616293" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2024 18:41:04 -0700 X-CSE-ConnectionGUID: euy1YoxJSXWNrUMm2pTZRg== X-CSE-MsgGUID: W77/LiSaThy8NMTG2VohtA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,194,1719903600"; d="scan'208";a="65191550" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2024 18:41:03 -0700 From: "Huang, Ying" To: Yanfei Xu Cc: akpm@linux-foundation.org, horen.chuang@linux.dev, Jonathan.Cameron@huawei.com, linux-mm@kvack.org Subject: Re: [PATCH] memory tier: fix deadlock warning while onlining pages In-Reply-To: (Yanfei Xu's message of "Fri, 30 Aug 2024 17:53:15 +0800") References: <20240827113614.1343049-1-yanfei.xu@intel.com> <87ed66h4d1.fsf@yhuang6-desk2.ccr.corp.intel.com> Date: Mon, 02 Sep 2024 09:37:29 +0800 Message-ID: <87wmjug7ja.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 6188B140004 X-Stat-Signature: ghgxa9h16gy6pdbmj9nrtkqhbw738xxo X-Rspam-User: X-HE-Tag: 1725241265-295400 X-HE-Meta: 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 w1cag5WC L9Yq58OlTYL4qOrOwL1NavQ6p4l78DEF9a8ZtzeDof5kwjxmtEGB8n7jd8RzpZVehbBgW0yqgLz5j9WRehAl21e5RwFnKdFrQnRfIH4Q5+Doe9ZaJcFm1gGVjMbh94ZPtA939RHyKTQbMgNJ2TN3ipG5Vrc9savPPZMi8 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Yanfei Xu writes: > [Snip] > > On 8/30/2024 3:11 PM, Huang, Ying wrote: >>> Fixes: 823430c8e9d9 ("memory tier: consolidate the initialization of memory tiers") >>> Signed-off-by: Yanfei Xu >>> --- >>> mm/memory-tiers.c | 1 - >>> 1 file changed, 1 deletion(-) >>> >>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c >>> index 4775b3a3dabe..dddcd6b38e28 100644 >>> --- a/mm/memory-tiers.c >>> +++ b/mm/memory-tiers.c >>> @@ -895,7 +895,6 @@ static int __init memory_tier_init(void) >>> WARN_ON(!node_demotion); >>> #endif >>> - guard(mutex)(&memory_tier_lock); >>> /* >>> * For now we can have 4 faster memory tiers with smaller adistance >>> * than default DRAM tier. >> Although it's not absolutely necessary, I still think that it's better >> to just revert the locking change of memory_tier_init() in commit >> 823430c8e9d9 ("memory tier: consolidate the initialization of memory >> tiers"). That is, to use mutex_lock/unlock() and exclude >> hotplug_memory_notifier() from the locked region. Because we will >> always hold memory_tier_lock when working on memory tier related data >> structures in this way. > > Thanks for pointing out it. Will do it as below in v2. > > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > index 4775b3a3dabe..ba3738b29cc5 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -895,13 +895,14 @@ static int __init memory_tier_init(void) > WARN_ON(!node_demotion); > #endif > > - guard(mutex)(&memory_tier_lock); > + mutex_lock(&memory_tier_lock); > /* > * For now we can have 4 faster memory tiers with smaller adistance > * than default DRAM tier. > */ > default_dram_type = > mt_find_alloc_memory_type(MEMTIER_ADISTANCE_DRAM, > &default_memory_types); > + mutex_unlock(&memory_tier_lock); > if (IS_ERR(default_dram_type)) > panic("%s() failed to allocate default DRAM tier\n", > __func__); > > LGTM, feel free to add in the future version. Reviewed-by: "Huang, Ying"