From: Dave Hansen <dave.hansen@intel.com>
To: Alexander Duyck <alexander.duyck@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Cc: rkrcmar@redhat.com, alexander.h.duyck@linux.intel.com,
x86@kernel.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
pbonzini@redhat.com, tglx@linutronix.de,
akpm@linux-foundation.org
Subject: Re: [RFC PATCH 3/4] kvm: Add guest side support for free memory hints
Date: Mon, 4 Feb 2019 11:44:29 -0800 [thread overview]
Message-ID: <24277842-c920-4a12-57d1-2ebcdf3c1534@intel.com> (raw)
In-Reply-To: <20190204181552.12095.46287.stgit@localhost.localdomain>
On 2/4/19 10:15 AM, Alexander Duyck wrote:
> +#ifdef CONFIG_KVM_GUEST
> +#include <linux/jump_label.h>
> +extern struct static_key_false pv_free_page_hint_enabled;
> +
> +#define HAVE_ARCH_FREE_PAGE
> +void __arch_free_page(struct page *page, unsigned int order);
> +static inline void arch_free_page(struct page *page, unsigned int order)
> +{
> + if (static_branch_unlikely(&pv_free_page_hint_enabled))
> + __arch_free_page(page, order);
> +}
> +#endif
So, this ends up with at least a call, a branch and a ret added to the
order-0 paths, including freeing pages to the per-cpu-pageset lists.
That seems worrisome.
What performance testing has been performed to look into the overhead
added to those paths?
next prev parent reply other threads:[~2019-02-04 19:44 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 18:15 [RFC PATCH 0/4] kvm: Report unused guest pages to host Alexander Duyck
2019-02-04 18:15 ` [RFC PATCH 1/4] madvise: Expose ability to set dontneed from kernel Alexander Duyck
2019-02-04 18:15 ` [RFC PATCH 2/4] kvm: Add host side support for free memory hints Alexander Duyck
2019-02-10 0:44 ` Michael S. Tsirkin
2019-02-11 17:34 ` Alexander Duyck
2019-02-11 17:34 ` Alexander Duyck
2019-02-11 17:36 ` Michael S. Tsirkin
2019-02-11 17:41 ` Dave Hansen
2019-02-11 17:48 ` Michael S. Tsirkin
2019-02-11 18:30 ` Alexander Duyck
2019-02-11 18:30 ` Alexander Duyck
2019-02-11 19:24 ` Michael S. Tsirkin
2019-02-04 18:15 ` [RFC PATCH 3/4] kvm: Add guest " Alexander Duyck
2019-02-04 19:44 ` Dave Hansen [this message]
2019-02-04 20:42 ` Alexander Duyck
2019-02-04 20:42 ` Alexander Duyck
2019-02-04 23:00 ` Nadav Amit
2019-02-04 23:37 ` Alexander Duyck
2019-02-04 23:37 ` Alexander Duyck
2019-02-05 0:03 ` Nadav Amit
2019-02-05 0:16 ` Alexander Duyck
2019-02-05 0:16 ` Alexander Duyck
2019-02-05 1:46 ` Nadav Amit
2019-02-05 18:09 ` Alexander Duyck
2019-02-05 18:09 ` Alexander Duyck
2019-02-07 18:21 ` Luiz Capitulino
2019-02-07 18:44 ` Alexander Duyck
2019-02-07 18:44 ` Alexander Duyck
2019-02-07 20:02 ` Luiz Capitulino
2019-02-07 20:02 ` Luiz Capitulino
2019-02-08 21:05 ` Nitesh Narayan Lal
2019-02-08 21:31 ` Alexander Duyck
2019-02-08 21:31 ` Alexander Duyck
2019-02-10 0:49 ` Michael S. Tsirkin
2019-02-11 16:31 ` Alexander Duyck
2019-02-11 16:31 ` Alexander Duyck
2019-02-11 17:36 ` Michael S. Tsirkin
2019-02-11 18:10 ` Alexander Duyck
2019-02-11 18:10 ` Alexander Duyck
2019-02-11 19:54 ` Michael S. Tsirkin
2019-02-11 21:00 ` Alexander Duyck
2019-02-11 21:00 ` Alexander Duyck
2019-02-11 22:52 ` Michael S. Tsirkin
2019-02-12 0:09 ` Alexander Duyck
2019-02-12 0:34 ` Michael S. Tsirkin
2019-02-11 17:48 ` Dave Hansen
2019-02-11 17:58 ` Michael S. Tsirkin
2019-02-11 18:19 ` Dave Hansen
2019-02-11 19:56 ` Michael S. Tsirkin
2019-02-04 18:15 ` [RFC PATCH 4/4] mm: Add merge page notifier Alexander Duyck
2019-02-04 19:40 ` Dave Hansen
2019-02-04 19:51 ` Alexander Duyck
2019-02-04 19:51 ` Alexander Duyck
2019-02-10 0:57 ` Michael S. Tsirkin
2019-02-11 13:30 ` Nitesh Narayan Lal
2019-02-11 14:17 ` Michael S. Tsirkin
2019-02-11 16:24 ` Nitesh Narayan Lal
2019-02-11 17:41 ` Michael S. Tsirkin
2019-02-11 18:09 ` Nitesh Narayan Lal
2019-02-11 6:40 ` Aaron Lu
2019-02-11 15:58 ` Alexander Duyck
2019-02-11 15:58 ` Alexander Duyck
2019-02-12 2:09 ` Aaron Lu
2019-02-12 17:20 ` Alexander Duyck
2019-02-12 17:20 ` Alexander Duyck
2019-02-04 18:19 ` [RFC PATCH QEMU] i386/kvm: Enable paravirtual unused page hint mechanism Alexander Duyck
2019-02-05 17:25 ` [RFC PATCH 0/4] kvm: Report unused guest pages to host Nitesh Narayan Lal
2019-02-05 18:43 ` Alexander Duyck
2019-02-05 18:43 ` Alexander Duyck
2019-02-07 14:48 ` Nitesh Narayan Lal
2019-02-07 16:56 ` Alexander Duyck
2019-02-07 16:56 ` Alexander Duyck
2019-02-10 0:51 ` Michael S. Tsirkin
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