From: Peter Xu <peterx@redhat.com>
To: LEROY Christophe <christophe.leroy2@cs-soprasteria.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Oscar Salvador <osalvador@suse.de>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
Michal Hocko <mhocko@kernel.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>,
Alex Williamson <alex.williamson@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
"x86@kernel.org" <x86@kernel.org>,
Alistair Popple <apopple@nvidia.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Ryan Roberts <ryan.roberts@arm.com>,
Hugh Dickins <hughd@google.com>,
Axel Rasmussen <axelrasmussen@google.com>
Subject: Re: [PATCH RFC 2/6] mm: PGTABLE_HAS_P[MU]D_LEAVES config options
Date: Mon, 26 Aug 2024 10:34:39 -0400 [thread overview]
Message-ID: <ZsySf2F9djR5YVOr@x1n> (raw)
In-Reply-To: <d3e4256f-253a-4a61-a83b-93f50ebabed8@cs-soprasteria.com>
On Fri, Aug 23, 2024 at 06:19:52AM +0000, LEROY Christophe wrote:
> Why is an option needed for that ? If pmd_leaf() returns always false,
> it means the arch doesn't support pmd mappings and if properly used all
> related code should fold away without a config option, shouldn't it ?
It's not always easy to leverage an "if" clause there, IIUC. Take the case
of when a driver wants to inject a pmd pfnmap, we may want something like:
if (pmd_leaf_supported())
inject_pmd_leaf(&pmd);
We don't have a pmd entry to reference at the point of pmd_leaf_supported()
when making the decision.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2024-08-26 14:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-17 22:02 [PATCH RFC 0/6] mm: THP-agnostic refactor on huge mappings Peter Xu
2024-07-17 22:02 ` [PATCH RFC 1/6] mm/treewide: Remove pgd_devmap() Peter Xu
2024-07-17 22:02 ` [PATCH RFC 2/6] mm: PGTABLE_HAS_P[MU]D_LEAVES config options Peter Xu
2024-08-22 17:22 ` LEROY Christophe
2024-08-22 19:16 ` Peter Xu
2024-08-23 6:19 ` LEROY Christophe
2024-08-26 14:34 ` Peter Xu [this message]
2024-07-17 22:02 ` [PATCH RFC 3/6] mm/treewide: Make pgtable-generic.c THP agnostic Peter Xu
2024-07-17 22:02 ` [PATCH RFC 4/6] mm: Move huge mapping declarations from internal.h to huge_mm.h Peter Xu
2024-07-17 22:02 ` [PATCH RFC 5/6] mm/huge_mapping: Create huge_mapping_pxx.c Peter Xu
2024-07-17 22:02 ` [PATCH RFC 6/6] mm: Convert "*_trans_huge() || *_devmap()" to use *_leaf() Peter Xu
2024-07-22 13:29 ` [PATCH RFC 0/6] mm: THP-agnostic refactor on huge mappings David Hildenbrand
2024-07-22 15:31 ` Peter Xu
2024-07-23 8:18 ` David Hildenbrand
2024-07-23 21:04 ` Peter Xu
2024-07-23 21:22 ` David Hildenbrand
2024-08-22 17:08 ` LEROY Christophe
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