Re: [PATCH v3 0/5] add persistent huge zero folio support
From: Kiryl Shutsemau <hidden>
Date: 2025-08-11 10:36:36
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linux-fsdevel, linux-mm, lkml
On Mon, Aug 11, 2025 at 12:21:23PM +0200, David Hildenbrand wrote:
On 11.08.25 12:17, Kiryl Shutsemau wrote:quoted
On Mon, Aug 11, 2025 at 11:09:24AM +0100, Lorenzo Stoakes wrote:quoted
On Mon, Aug 11, 2025 at 11:07:48AM +0100, Kiryl Shutsemau wrote:quoted
Well, my worry is that 2M can be a high tax for smaller machines. Compile-time might be cleaner, but it has downsides. It is also not clear if these users actually need physical HZP or virtual is enough. Virtual is cheap.The kernel config flag (default =N) literally says don't use unless you have plenty of memory :) So this isn't an issue.Distros use one-config-fits-all approach. Default N doesn't help anything.You'd probably want a way to say "use the persistent huge zero folio if you machine has more than X Gigs". That's all reasonable stuff that can be had on top of this series.
We have 'totalram_pages() < (512 << (20 - PAGE_SHIFT))' check in hugepage_init(). It can [be abstracted out and] re-used. -- Kiryl Shutsemau / Kirill A. Shutemov