From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>, Jann Horn <jannh@google.com>,
Vasant Hegde <vasant.hegde@amd.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
Alistair Popple <apopple@nvidia.com>,
Peter Zijlstra <peterz@infradead.org>,
Uladzislau Rezki <urezki@gmail.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Andy Lutomirski <luto@kernel.org>, "Lai, Yi1" <yi1.lai@intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"security@kernel.org" <security@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v4 6/8] mm: Introduce deferred freeing for kernel page tables
Date: Mon, 15 Sep 2025 08:35:09 -0300 [thread overview]
Message-ID: <20250915113509.GA1024672@nvidia.com> (raw)
In-Reply-To: <BL1PR11MB5271A6FA21418DD8486089AB8C08A@BL1PR11MB5271.namprd11.prod.outlook.com>
On Fri, Sep 12, 2025 at 08:17:23AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Saturday, September 6, 2025 2:44 AM
> >
> > On Fri, Sep 05, 2025 at 01:51:01PM +0800, Lu Baolu wrote:
> >
> > > + list_for_each_entry_safe(pt, next, &page_list, pt_list) {
> > > + list_del(&pt->pt_list);
> >
> > The list_del isn't necessary, it doesn't zero the list, just _safe
> > iteration is fine.
> >
>
> if no list_del why need to keep the _safe iteration?
__pagetable_free() can change the memory holding pt->pt-list, it is
like kfree. So _safe is needed to allow that.
_safe is not just about deletion, anything that could change the list
element must use a safe iteration.
Jason
next prev parent reply other threads:[~2025-09-15 11:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-05 5:50 [PATCH v4 0/8] Fix stale IOTLB entries for kernel address space Lu Baolu
2025-09-05 5:50 ` [PATCH v4 1/8] mm: Add a ptdesc flag to mark kernel page tables Lu Baolu
2025-09-05 18:24 ` Jason Gunthorpe
2025-09-12 7:58 ` Tian, Kevin
2025-09-05 5:50 ` [PATCH v4 2/8] mm: Actually mark kernel page table pages Lu Baolu
2025-09-05 18:24 ` Jason Gunthorpe
2025-09-12 7:59 ` Tian, Kevin
2025-09-05 5:50 ` [PATCH v4 3/8] x86/mm: Use 'ptdesc' when freeing PMD pages Lu Baolu
2025-09-05 18:25 ` Jason Gunthorpe
2025-09-12 8:03 ` Tian, Kevin
2025-09-05 5:50 ` [PATCH v4 4/8] mm: Introduce pure page table freeing function Lu Baolu
2025-09-05 18:31 ` Jason Gunthorpe
2025-09-12 8:04 ` Tian, Kevin
2025-09-05 5:51 ` [PATCH v4 5/8] x86/mm: Use pagetable_free() Lu Baolu
2025-09-05 18:41 ` Jason Gunthorpe
2025-09-05 19:22 ` Dave Hansen
2025-09-05 20:11 ` Dave Hansen
2025-09-05 23:04 ` Jason Gunthorpe
2025-09-19 5:31 ` Baolu Lu
2025-09-05 5:51 ` [PATCH v4 6/8] mm: Introduce deferred freeing for kernel page tables Lu Baolu
2025-09-05 18:43 ` Jason Gunthorpe
2025-09-05 19:26 ` Dave Hansen
2025-09-12 8:17 ` Tian, Kevin
2025-09-15 11:35 ` Jason Gunthorpe [this message]
2025-09-19 8:18 ` Tian, Kevin
2025-09-12 8:14 ` Tian, Kevin
2025-09-15 1:16 ` Baolu Lu
2025-09-05 5:51 ` [PATCH v4 7/8] mm: Hook up Kconfig options for async page table freeing Lu Baolu
2025-09-05 18:44 ` Jason Gunthorpe
2025-09-12 8:19 ` Tian, Kevin
2025-09-05 5:51 ` [PATCH v4 8/8] iommu/sva: Invalidate stale IOTLB entries for kernel address space Lu Baolu
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