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[34.124.129.10]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82b0410b1bdsm2240439b3a.57.2026.03.20.04.01.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Mar 2026 04:01:34 -0700 (PDT) Date: Fri, 20 Mar 2026 11:01:25 +0000 From: Pranjal Shrivastava To: Vipin Sharma Cc: Samiullah Khawaja , David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Jason Gunthorpe , Robin Murphy , Kevin Tian , Alex Williamson , Shuah Khan , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Saeed Mahameed , Adithya Jayachandran , Parav Pandit , Leon Romanovsky , William Tu , Pratyush Yadav , Pasha Tatashin , David Matlack , Andrew Morton , Chris Li , YiFei Zhu Subject: Re: [PATCH 04/14] iommu/pages: Add APIs to preserve/unpreserve/restore iommu pages Message-ID: References: <20260203220948.2176157-1-skhawaja@google.com> <20260203220948.2176157-5-skhawaja@google.com> <20260317202925.GA2582517.vipinsh@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260317202925.GA2582517.vipinsh@google.com> On Tue, Mar 17, 2026 at 01:59:03PM -0700, Vipin Sharma wrote: > On Tue, Feb 03, 2026 at 10:09:38PM +0000, Samiullah Khawaja wrote: > > + [------- snip >8 --------] > > +EXPORT_SYMBOL_GPL(iommu_unpreserve_pages); > > + > > +void iommu_restore_page(u64 phys) > > +{ > > + struct ioptdesc *iopt; > > + struct folio *folio; > > + unsigned long pgcnt; > > + unsigned int order; > > + > > + folio = kho_restore_folio(phys); > > + BUG_ON(!folio); > > + > > + iopt = folio_ioptdesc(folio); > > + > > + order = folio_order(folio); > > + pgcnt = 1UL << order; > > + mod_node_page_state(folio_pgdat(folio), NR_IOMMU_PAGES, pgcnt); > > + lruvec_stat_mod_folio(folio, NR_SECONDARY_PAGETABLE, pgcnt); > > Above two functions are also used in other two places in this file, lets > create a common function for these two operations. > I was thinking about this, out of the 2 other places one is `__iommu_free_desc` where we are supposed to subtract pgcnt.. but I think we can follow the -pgcnt pattern we have currently and add a helper `iommu_folio_update_stats(folio, pgcnt)` where we can pass -pgcnt to subtract nr_pages? Something like: +static inline void iommu_folio_update_stats(struct folio *folio, long nr_pages) +{ + mod_node_page_state(folio_pgdat(folio), NR_IOMMU_PAGES, nr_pages); + lruvec_stat_mod_folio(folio, NR_SECONDARY_PAGETABLE, nr_pages); +} @@ -86,8 +91,7 @@ static void __iommu_free_desc(struct ioptdesc *iopt) if (IOMMU_PAGES_USE_DMA_API) WARN_ON_ONCE(iopt->incoherent); - mod_node_page_state(folio_pgdat(folio), NR_IOMMU_PAGES, -pgcnt); - lruvec_stat_mod_folio(folio, NR_SECONDARY_PAGETABLE, -pgcnt); + iommu_folio_update_stats(folio, -(long)pgcnt); folio_put(folio); } But I'm unsure if passing -(long)pgcnt is a good idea? > > +} > > +EXPORT_SYMBOL_GPL(iommu_restore_page); > > + Thanks, Praan