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AJvYcCVu1UiEsf4Ef3sAMj4cRkRtDijdXMVq4hsvagu1ghvbwBf6Ii0JEqnyjKPnen8AhL0pGNuRrUCUfw==@kvack.org X-Gm-Message-State: AOJu0YwXMsqCt/G5f6U4GTj0OeGuAHg4NIQAjy1ADuppH/XFtRYftHYD SpT9eMgWqXrQQCOuS5vRCPMDWWxS6XOrOqTRf7tzDzB11Mtapd/FBCAMCtz30jYH1m4zHjS3yVp 1TupancBhIm6B6g== X-Google-Smtp-Source: AGHT+IEFiLJX44hMWNXHZC3Aih1gij7lk8DQBXxxJ2bwgJL5TDkN/S5/hEJ472CJdxkQKTEOJdcGAy+su2hzzQ== X-Received: from edf6.prod.google.com ([2002:a05:6402:21c6:b0:639:c8c6:de62]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:26d1:b0:63e:14c2:2818 with SMTP id 4fb4d7f45d1cf-63e14c22f06mr15645925a12.17.1761517763982; Sun, 26 Oct 2025 15:29:23 -0700 (PDT) Date: Sun, 26 Oct 2025 22:29:23 +0000 In-Reply-To: <20251025114801.GWaPy48dhlZ_EVoqKi@fat_crate.local> Mime-Version: 1.0 References: <20250924-b4-asi-page-alloc-v1-0-2d861768041f@google.com> <20250924-b4-asi-page-alloc-v1-3-2d861768041f@google.com> <20251025114801.GWaPy48dhlZ_EVoqKi@fat_crate.local> X-Mailer: aerc 0.21.0 Message-ID: Subject: Re: [PATCH 03/21] x86/mm: factor out phys_pgd_init() From: Brendan Jackman To: Borislav Petkov , Brendan Jackman Cc: Andy Lutomirski , Lorenzo Stoakes , "Liam R. Howlett" , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Axel Rasmussen , Yuanchu Xie , Roman Gushchin , , , , , , , , , , , , , , , , Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Queue-Id: BCA91100003 X-Rspamd-Server: rspam02 X-Stat-Signature: 6ywe4enmhwron45adigo9nbmjtdt1c7k X-HE-Tag: 1761517765-542342 X-HE-Meta: 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 8ertw4Ey 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 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: On Sat Oct 25, 2025 at 11:48 AM UTC, Borislav Petkov wrote: > On Wed, Sep 24, 2025 at 02:59:38PM +0000, Brendan Jackman wrote: >> +static unsigned long __meminit >> +__kernel_physical_mapping_init(unsigned long paddr_start, >> + unsigned long paddr_end, >> + unsigned long page_size_mask, >> + pgprot_t prot, bool init) >> +{ >> + bool pgd_changed; > > I have to say, that pgd_changed is yuck but I don't have a better idea and > this has happened a long time ago anyway. > > How about you have the caller pass in false: > > bool pgd_changed = false; > > and then callee sets it to true when it does so? Sure. Per Dave's feedback I am still slightly hopeful I can find a way to come in and refactor this code so that it's gets cleaner for you guys and then ASI becomes a natural addition. So far I don't come up with anything in init_64.c but I'm still planning to stare at set_memory.c a while longer and see if anything comes to mind. So maybe we'll be able to reduce the yuck factor a bit. >> + unsigned long paddr_last; > > The tip-tree preferred ordering of variable declarations at the > beginning of a function is reverse fir tree order:: > > struct long_struct_name *descriptive_name; > unsigned long foo, bar; > unsigned int tmp; > int ret; > > The above is faster to parse than the reverse ordering:: > > int ret; > unsigned int tmp; > unsigned long foo, bar; > struct long_struct_name *descriptive_name; > > And even more so than random ordering:: > > unsigned long foo, bar; > int ret; > struct long_struct_name *descriptive_name; > unsigned int tmp; Ack >> + >> + paddr_last = phys_pgd_init(init_mm.pgd, paddr_start, paddr_end, page_size_mask, >> + prot, init, &pgd_changed); >> + if (pgd_changed) >> + sync_global_pgds((unsigned long)__va(paddr_start), >> + (unsigned long)__va(paddr_end) - 1); >> + >> + return paddr_last; >> +} >> >> /* >> * Create page table mapping for the physical memory for specific physical >> >> -- >> 2.50.1 >>