From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Hillf Danton <hdanton@sina.com>
Cc: linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shakeel Butt <shakeelb@google.com>,
Minchan Kim <minchan@kernel.org>, Mel Gorman <mgorman@suse.de>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Jan Kara <jack@suse.cz>
Subject: Re: [RFC v2] mm: add page preemption
Date: Mon, 28 Oct 2019 15:26:09 +0300 [thread overview]
Message-ID: <20191028122609.k5suvp7b57oxglvj@box> (raw)
In-Reply-To: <20191026112808.14268-1-hdanton@sina.com>
On Sat, Oct 26, 2019 at 07:28:08PM +0800, Hillf Danton wrote:
> @@ -218,6 +219,9 @@ struct page {
>
> #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
> int _last_cpupid;
> +#else
> + int prio;
> +#define CONFIG_PAGE_PREEMPTION PP
> #endif
> } _struct_page_alignment;
>
No.
There's a really good reason we trying hard to push the _last_cpuid into
page flags instead of growing the struct page by 4 bytes.
I don't think your feature worth 0.1% of RAM and a lot of cache misses
that this change would generate.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-10-28 12:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-26 11:28 Hillf Danton
2019-10-28 12:26 ` Kirill A. Shutemov [this message]
2019-10-28 13:55 ` Hillf Danton
2019-10-28 15:56 ` Johannes Weiner
2019-10-29 3:04 ` Hillf Danton
2019-10-29 8:41 ` Michal Hocko
2019-10-29 15:27 ` Johannes Weiner
2019-10-29 12:30 ` Hillf Danton
2019-10-29 13:26 ` David Hildenbrand
2019-10-29 13:41 ` Michal Hocko
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