Messages in this thread | | | From | "Song Bao Hua (Barry Song)" <> | Subject | RE: [External] RE: [PATCH v4 00/21] Free some vmemmap pages of hugetlb page | Date | Wed, 18 Nov 2020 03:27:56 +0000 |
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> -----Original Message----- > From: Oscar Salvador [mailto:osalvador@suse.de] > Sent: Wednesday, November 18, 2020 8:45 AM > To: Muchun Song <songmuchun@bytedance.com> > Cc: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>; > corbet@lwn.net; mike.kravetz@oracle.com; tglx@linutronix.de; > mingo@redhat.com; bp@alien8.de; x86@kernel.org; hpa@zytor.com; > dave.hansen@linux.intel.com; luto@kernel.org; peterz@infradead.org; > viro@zeniv.linux.org.uk; akpm@linux-foundation.org; paulmck@kernel.org; > mchehab+huawei@kernel.org; pawan.kumar.gupta@linux.intel.com; > rdunlap@infradead.org; oneukum@suse.com; anshuman.khandual@arm.com; > jroedel@suse.de; almasrymina@google.com; rientjes@google.com; > willy@infradead.org; mhocko@suse.com; duanxiongchun@bytedance.com; > linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; linux-mm@kvack.org; > linux-fsdevel@vger.kernel.org > Subject: Re: [External] RE: [PATCH v4 00/21] Free some vmemmap pages of > hugetlb page > > On 2020-11-17 17:29, Muchun Song wrote: > > Now for the 2MB HugrTLB page, we only free 6 vmemmap pages. > > But your words woke me up. Maybe we really can free 7 vmemmap > > pages. In this case, we can see 8 of the 512 struct page structures > > has beed set PG_head flag. If we can adjust compound_head() > > slightly and make compound_head() return the real head struct > > page when the parameter is the tail struct page but with PG_head > > flag set. I will start an investigation and a test. > > I would not overcomplicate things at this stage, but rather keep it > simple as the code is already tricky enough(without counting the LOC > thatvit adds). > We can always build on top later on in order to improve things.
Yep. I am not expecting freeing tail page to be done at this stage. This could be something in the todo list after the first patchset is solid.
> > -- > Oscar Salvador > SUSE L3
Thanks Barry
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