From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Huan Yang <link@vivo.com>,
akpm@linux-foundation.org, bingbu.cao@linux.intel.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
lorenzo.stoakes@oracle.com, opensource.kernel@vivo.com,
rppt@kernel.org, ryan.roberts@arm.com, urezki@gmail.com,
ziy@nvidia.com, vivek.kasireddy@intel.com,
"Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Subject: Re: [PATCH] mm/vmalloc: fix mischeck pfn valid in vmap_pfns
Date: Mon, 24 Mar 2025 02:57:45 +0000 [thread overview]
Message-ID: <Z-DKKQcc0dSdSrw8@casper.infradead.org> (raw)
In-Reply-To: <20250318083330.GB18902@lst.de>
On Tue, Mar 18, 2025 at 09:33:30AM +0100, Christoph Hellwig wrote:
> On Tue, Mar 18, 2025 at 04:20:17PM +0800, Huan Yang wrote:
> > This prevents us from properly invoking vmap, which is why we have turned to using vmap_pfn instead.
> >
> > Even if a folio-based vmap is implemented, it still cannot handle mapping multiple folio ranges of physical
> >
> > memory to vmalloc regions. A range of folio is important, it maybe an offset in memfd, no need entire folio.
> >
> > So, I still consider vmap_pfn to be the optimal solution for this specific scenario. :)
>
> No, vmap_pfn is entirely for memory not backed by pages or folios,
> i.e. PCIe BARs and similar memory. This must not be mixed with proper
> folio backed memory.
>
> So you'll need a vmap for folios to support this use case.
https://lore.kernel.org/linux-mm/20250131001806.92349-1-vishal.moola@gmail.com/
seems like a good match for "we need to vmap a range from a file".
Vishal has some updates since this version, and I'm sure he can send
them out after LSFMM.
next prev parent reply other threads:[~2025-03-24 2:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-12 6:15 Huan Yang
2025-03-12 6:18 ` Christoph Hellwig
2025-03-17 2:12 ` Huan Yang
2025-03-17 5:29 ` Bingbu Cao
2025-03-17 5:53 ` Christoph Hellwig
2025-03-17 7:42 ` Huan Yang
2025-03-18 6:48 ` Christoph Hellwig
2025-03-18 8:20 ` Huan Yang
2025-03-18 8:33 ` Christoph Hellwig
2025-03-18 8:39 ` Huan Yang
2025-03-18 8:44 ` Christoph Hellwig
2025-03-18 8:50 ` Huan Yang
[not found] ` <20250319050359.3484-1-hdanton@sina.com>
2025-03-19 8:08 ` Christoph Hellwig
[not found] ` <20250319112651.3502-1-hdanton@sina.com>
2025-03-24 2:13 ` Huan Yang
2025-03-25 6:32 ` Kasireddy, Vivek
2025-03-25 6:46 ` Bingbu Cao
2025-03-27 13:40 ` Matthew Wilcox
2025-03-28 6:13 ` Huan Yang
2025-03-19 9:09 ` Gao Xiang
2025-03-20 5:31 ` Christoph Hellwig
2025-03-24 2:22 ` Huan Yang
2025-03-24 2:57 ` Matthew Wilcox [this message]
2025-03-17 6:26 ` Huan Yang
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