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Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song Subject: Re: [PATCH v7 08/14] KVM: Rename mmu_notifier_* Message-ID: <20230525085400.GP4253@hirez.programming.kicks-ass.net> References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> <20220706082016.2603916-9-chao.p.peng@linux.intel.com> <20230524203336.GC3447678@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 15B00180007 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 3jtmx31kfjmdon5sretr1d1qdcn5d9eu X-HE-Tag: 1685004887-86941 X-HE-Meta: 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 HlwceLN0 a+B1BuJxyjOQB4CCiu7Ut4Wc/zOf8AF31Mp29R/+o61eiHepPzqqzb7lPBeoQlNCDLLemekQ/U0FyWlR+xi7oprAnijihiOSFQurqnhyaJfFK6Z+yFTD1axzHykR/rbT6rfy3r+jXLFgNR+WbR+BTuI3/suO2qk3I3JvokT8xULI3GK80B2otWq1o3lpkE+IZG3tz+scJc0BBZrc= 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 Wed, May 24, 2023 at 02:39:50PM -0700, Sean Christopherson wrote: > On Wed, May 24, 2023, Peter Zijlstra wrote: > > On Wed, May 24, 2023 at 01:16:03PM -0700, Sean Christopherson wrote: > > > Of course, the only accesses outside of mmu_lock are reads, so on x86 that > > > "atomic" access is just a READ_ONCE() load, but that's not the case for all > > > architectures. > > > > This is true on *all* archs. atomic_set() and atomic_read() are no more > > and no less than WRITE_ONCE() / READ_ONCE(). > > Ah, I take it s390's handcoded assembly routines are just a paranoid equivalents > and not truly special? "l" and "st" do sound quite generic... Yep, compiler *should* generate the same with READ_ONCE/WRITE_ONCE.