From: Dave Hansen <dave.hansen@intel.com>
To: David Hildenbrand <david@redhat.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Kevin Tian <kevin.tian@intel.com>,
Jason Gunthorpe <jgg@nvidia.com>, Jann Horn <jannh@google.com>,
Vasant Hegde <vasant.hegde@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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>, Yi Lai <yi1.lai@intel.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
Michal Hocko <mhocko@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: iommu@lists.linux.dev, security@kernel.org, x86@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v7 7/8] mm: Introduce deferred freeing for kernel page tables
Date: Wed, 22 Oct 2025 12:12:36 -0700 [thread overview]
Message-ID: <fd0147dc-d785-4676-9c8d-824d2c709320@intel.com> (raw)
In-Reply-To: <dabf557c-d83b-4edb-8cf3-1ab8581e5406@redhat.com>
On 10/22/25 11:34, David Hildenbrand wrote:
...
> I was briefly wondering whether the pages can get stuck in there
> sufficiently long that we would want to wire up the shrinker to say
> "OOM, hold your horses, we can still free something here".
>
> But I'd assume the workqueue will get scheduled in a reasonable
> timeframe either so this is not a concern?
First, I can't fathom there will ever be more than a couple of pages in
there.
If there's an OOM going on, there's probably no shortage of idle time
leading up to and during the OOM as threads plow into mutexes and wait
for I/O. That's when the work will get handled even more quickly than
normal.
I suspect it'll work itself out naturally. It wouldn't be hard to toss a
counter in there for the list length and dump it at OOM, or pr_info() if
it's got more than a few pages on it.
next prev parent reply other threads:[~2025-10-22 19:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-22 8:26 [PATCH v7 0/8] Fix stale IOTLB entries for kernel address space Lu Baolu
2025-10-22 8:26 ` [PATCH v7 1/8] iommu: Disable SVA when CONFIG_X86 is set Lu Baolu
2025-10-22 19:50 ` Jason Gunthorpe
2025-10-22 8:26 ` [PATCH v7 2/8] mm: Add a ptdesc flag to mark kernel page tables Lu Baolu
2025-10-22 18:31 ` David Hildenbrand
2025-10-23 7:07 ` Mike Rapoport
2025-10-22 8:26 ` [PATCH v7 3/8] mm: Actually mark kernel page table pages Lu Baolu
2025-10-22 8:26 ` [PATCH v7 4/8] x86/mm: Use 'ptdesc' when freeing PMD pages Lu Baolu
2025-10-22 18:31 ` David Hildenbrand
2025-10-22 8:26 ` [PATCH v7 5/8] mm: Introduce pure page table freeing function Lu Baolu
2025-10-22 8:26 ` [PATCH v7 6/8] x86/mm: Use pagetable_free() Lu Baolu
2025-11-18 2:14 ` Vishal Moola (Oracle)
2025-11-20 10:35 ` Mike Rapoport
2025-10-22 8:26 ` [PATCH v7 7/8] mm: Introduce deferred freeing for kernel page tables Lu Baolu
2025-10-22 18:34 ` David Hildenbrand
2025-10-22 19:12 ` Dave Hansen [this message]
2025-10-22 19:52 ` Jason Gunthorpe
2025-10-23 7:10 ` Mike Rapoport
2025-10-22 8:26 ` [PATCH v7 8/8] iommu/sva: Invalidate stale IOTLB entries for kernel address space Lu Baolu
2025-10-22 19:01 ` [PATCH v7 0/8] Fix " Andrew Morton
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