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Mon, 21 Dec 2020 07:18:47 -0800 (PST) MIME-Version: 1.0 References: <20201217121303.13386-1-songmuchun@bytedance.com> <20201217121303.13386-5-songmuchun@bytedance.com> <20201221102703.GA15804@linux> <20201221141242.GA19680@linux> In-Reply-To: <20201221141242.GA19680@linux> From: Muchun Song Date: Mon, 21 Dec 2020 23:18:11 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v10 04/11] mm/hugetlb: Defer freeing of HugeTLB pages To: Oscar Salvador Cc: Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Michal Hocko , "Song Bao Hua (Barry Song)" , David Hildenbrand , naoya.horiguchi@nec.com, Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Content-Type: text/plain; charset="UTF-8" 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: On Mon, Dec 21, 2020 at 10:14 PM Oscar Salvador wrote: > > On Mon, Dec 21, 2020 at 07:07:18PM +0800, Muchun Song wrote: > > > The above implies that update_and_free_page() is __always__ called from a > > > non-task context, but that is not always the case? > > > > IIUC, here is always the case. > > I might be missing something obvious, so bear with me. > > I guess you are refering to the call __free_huge_page()->update_and_free_page(). > AFAICS, free_huge_page might call __free_huge_page right away when in task > context, and so, we would be calling update_and_free in a task context as well. Yeah. You are right. I mean the call __free_huge_page()->update_and_free_page(). Because update_and_free_page is called under hugetlb_lock, it is non-task context, right? > > Or are you referring to the other callers? > > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun