From: Mike Rapoport <rppt@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Yajun Deng <yajun.deng@linux.dev>,
akpm@linux-foundation.org, mike.kravetz@oracle.com,
muchun.song@linux.dev, glider@google.com, elver@google.com,
dvyukov@google.com, osalvador@suse.de, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com
Subject: Re: [PATCH 1/4] mm: pass set_count and set_reserved to __init_single_page
Date: Fri, 22 Sep 2023 11:08:31 +0300 [thread overview]
Message-ID: <20230922080831.GH3303@kernel.org> (raw)
In-Reply-To: <2ed9a6c5-bd36-9b9b-7022-34e7ae894f3a@redhat.com>
On Fri, Sep 22, 2023 at 09:48:59AM +0200, David Hildenbrand wrote:
> On 22.09.23 09:47, Matthew Wilcox wrote:
> > On Fri, Sep 22, 2023 at 03:09:20PM +0800, Yajun Deng wrote:
> > > - __init_single_page(page, pfn, zone, nid);
> > > + __init_single_page(page, pfn, zone, nid, true, false);
> >
> > So Linus has just had a big rant about not doing bool flags to
> > functions. And in particular _multiple_ bool flags to functions.
> >
> > ie this should be:
> >
> > #define INIT_PAGE_COUNT (1 << 0)
> > #define INIT_PAGE_RESERVED (1 << 1)
> >
> > __init_single_page(page, pfn, zone, nid, INIT_PAGE_COUNT);
> >
> > or something similar.
> >
> > I have no judgement on the merits of this patch so far. Do you have
> > performance numbers for each of these patches? Some of them seem quite
> > unlikely to actually help, at least on a machine which is constrained
> > by cacheline fetches.
>
> The last patch contains
>
> before:
> node 0 deferred pages initialised in 78ms
>
> after:
> node 0 deferred pages initialised in 72ms
>
> Not earth-shattering :D Maybe with much bigger machines relevant?
Patch 3 contains
The following data was tested on an x86 machine with 190GB of RAM.
before:
free_low_memory_core_early() 342ms
after:
free_low_memory_core_early() 286ms
Which is more impressive, but still I'm not convinced that it's worth the
added complexity and potential subtle bugs.
> --
> Cheers,
>
> David / dhildenb
>
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2023-09-22 8:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 7:09 [PATCH 0/4] mm: Don't set and reset page count in MEMINIT_EARLY Yajun Deng
2023-09-22 7:09 ` [PATCH 1/4] mm: pass set_count and set_reserved to __init_single_page Yajun Deng
2023-09-22 7:47 ` Matthew Wilcox
2023-09-22 7:48 ` David Hildenbrand
2023-09-22 8:08 ` Mike Rapoport [this message]
2023-09-22 7:09 ` [PATCH 2/4] mm: Introduce MEMINIT_LATE context Yajun Deng
2023-09-22 7:09 ` [PATCH 3/4] mm: Set page count and mark page reserved in reserve_bootmem_region Yajun Deng
2023-09-22 7:09 ` [PATCH 4/4] mm: don't set page count in deferred_init_pages Yajun Deng
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