From: Hugh Dickins <hughd@google.com>
To: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>,
"Vishal Moola (Oracle)" <vishal.moola@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-openrisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org, xen-devel@lists.xenproject.org,
kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Huacai Chen <chenhuacai@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Dinh Nguyen <dinguyen@kernel.org>,
Jonas Bonn <jonas@southpole.se>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
"David S. Miller" <davem@davemloft.net>,
Richard Weinberger <richard@nod.at>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Dave Hansen <dave.hansen@linux.intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: Re: [PATCH v6 00/33] Split ptdesc from struct page
Date: Tue, 27 Jun 2023 13:13:49 -0700 (PDT) [thread overview]
Message-ID: <90e643ca-de72-2f4c-f4fe-35e06e1a9277@google.com> (raw)
In-Reply-To: <ac1c162c-07d8-6084-44ca-a2c1a4183df2@redhat.com>
On Tue, 27 Jun 2023, David Hildenbrand wrote:
> On 27.06.23 06:44, Hugh Dickins wrote:
> > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> >
> >> The MM subsystem is trying to shrink struct page. This patchset
> >> introduces a memory descriptor for page table tracking - struct ptdesc.
> > ...
> >> 39 files changed, 686 insertions(+), 455 deletions(-)
> >
> > I don't see the point of this patchset: to me it is just obfuscation of
> > the present-day tight relationship between page table and struct page.
> >
> > Matthew already explained:
> >
> >> The intent is to get ptdescs to be dynamically allocated at some point
> >> in the ~2-3 years out future when we have finished the folio project ...
> >
> > So in a kindly mood, I'd say that this patchset is ahead of its time.
> > But I can certainly adapt to it, if everyone else sees some point to it.
>
> I share your thoughts, that code churn which will help eventually in the far,
> far future (not wanting to sound too pessimistic, but it's not going to be
> there tomorrow ;) ).
>
> However, if it's just the same as the other conversions we already did (e.g.,
> struct slab), then I guess there is no reason to stop now -- the obfuscation
> already happened.
>
> ... or is there a difference regarding this conversion and the previous ones?
I was aware of the struct slab thing, didn't see much point there myself
either; but it was welcomed by Vlastimil, and barely affected outside of
slab allocators, so I had no reason to object.
You think that if a little unnecessary churn (a *lot* of churn if you
include folios, which did save some repeated calls to compound_head())
has already occurred, that's a good precedent for allowing more and more?
My opinion happens to differ on that.
Hugh
next prev parent reply other threads:[~2023-06-27 20:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-27 3:13 [PATCH v6 00/33] Split ptdesc from struct page Vishal Moola (Oracle)
2023-06-27 3:13 ` [PATCH v6 01/33] mm: Add PAGE_TYPE_OP folio functions Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 02/33] s390: Use _pt_s390_gaddr for gmap address tracking Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 03/33] pgtable: Create struct ptdesc Vishal Moola (Oracle)
2023-06-27 16:07 ` Peter Xu
2023-06-27 17:51 ` Vishal Moola
2023-06-27 3:14 ` [PATCH v6 04/33] mm: add utility functions for ptdesc Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 05/33] mm: Convert pmd_pgtable_page() to pmd_ptdesc() Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 06/33] mm: Convert ptlock_alloc() to use ptdescs Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 07/33] mm: Convert ptlock_ptr() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 08/33] mm: Convert pmd_ptlock_init() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 09/33] mm: Convert ptlock_init() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 10/33] mm: Convert pmd_ptlock_free() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 11/33] mm: Convert ptlock_free() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 12/33] mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor} Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 13/33] powerpc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 14/33] x86: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 15/33] s390: Convert various gmap " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 16/33] s390: Convert various pgalloc " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 17/33] mm: Remove page table members from struct page Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 18/33] pgalloc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 19/33] arm: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 20/33] arm64: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 21/33] csky: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 22/33] hexagon: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 23/33] loongarch: Convert various functions " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 24/33] m68k: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 25/33] mips: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 26/33] nios2: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 27/33] openrisc: " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 28/33] riscv: Convert alloc_{pmd, pte}_late() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 29/33] sh: Convert pte_free_tlb() " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 30/33] sparc64: Convert various functions " Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 31/33] sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 32/33] um: Convert {pmd, pte}_free_tlb() to use ptdescs Vishal Moola (Oracle)
2023-06-27 3:14 ` [PATCH v6 33/33] mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers Vishal Moola (Oracle)
2023-06-27 4:44 ` [PATCH v6 00/33] Split ptdesc from struct page Hugh Dickins
2023-06-27 7:14 ` David Hildenbrand
2023-06-27 20:13 ` Hugh Dickins [this message]
2023-06-28 7:41 ` David Hildenbrand
2023-06-28 18:51 ` Matthew Wilcox
2023-06-27 15:57 ` Matthew Wilcox
2023-06-27 20:25 ` Hugh Dickins
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