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Shutemov" , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Russell King , "David S. Miller" , Michael Ellerman , "Aneesh Kumar K.V" , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , Alexander Gordeev , Jann Horn , linux-arm-kernel@lists.infradead.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 02/12] mm/pgtable: add PAE safety to __pte_offset_map() Message-ID: References: <35e983f5-7ed3-b310-d949-9ae8b130cdab@google.com> <923480d5-35ab-7cac-79d0-343d16e29318@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <923480d5-35ab-7cac-79d0-343d16e29318@google.com> X-Rspamd-Queue-Id: 15D6480010 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: cso7pda7gytdg8tda9zo1rbschkbjouo X-HE-Tag: 1685368722-507436 X-HE-Meta: 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 jTGGHOaD sgYyVKshN6omtL85axtJe9XV3BSzeefPG7EmHI/WyXuQhrkxPQ3mW4BGFsJJJytjmov3VJCpRfZ2IJaQ7PMwwDTlfNjHO5xDSMxKanetC+/c89uvYZ4qbMr8+Mrw+vTNiIZKzP3U5b8iWBXHmUdfddh2JDHoXs/v1x+ECqhy8H+cmlg/891DbpizeaPVPZwYOlKed89SxfEzIvJ5z7ednXurrsg== 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 Sun, May 28, 2023 at 11:16:16PM -0700, Hugh Dickins wrote: > +#if defined(CONFIG_GUP_GET_PXX_LOW_HIGH) && \ > + (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RCU)) > +/* > + * See the comment above ptep_get_lockless() in include/linux/pgtable.h: > + * the barriers in pmdp_get_lockless() cannot guarantee that the value in > + * pmd_high actually belongs with the value in pmd_low; but holding interrupts > + * off blocks the TLB flush between present updates, which guarantees that a > + * successful __pte_offset_map() points to a page from matched halves. > + */ > +#define config_might_irq_save(flags) local_irq_save(flags) > +#define config_might_irq_restore(flags) local_irq_restore(flags) > +#else > +#define config_might_irq_save(flags) > +#define config_might_irq_restore(flags) I don't like the name. It should indicate that it's PMD-related, so pmd_read_start(flags) / pmd_read_end(flags)?