From: Dave Hansen <dave.hansen@intel.com>
To: Oscar Salvador <osalvador@suse.de>,
Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/4] x86/vmemmap: Optimize for consecutive sections in partial populated PMDs
Date: Tue, 9 Mar 2021 10:50:51 -0800 [thread overview]
Message-ID: <f8a1fc19-91bb-7f85-301f-6a68ea22b594@intel.com> (raw)
In-Reply-To: <20210309174113.5597-5-osalvador@suse.de>
On 3/9/21 9:41 AM, Oscar Salvador wrote:
> We can optimize in the case we are adding consecutive sections, so no
> memset(PAGE_UNUSED) is needed.
> In that case, let us keep track where the unused range of the previous
> memory range begins, so we can compare it with start of the range to be
> added.
> If they are equal, we know sections are added consecutively.
>
> For that purpose, let us introduce 'unused_pmd_start', which always holds
> the beginning of the unused memory range.
>
> In the case a section does not contiguously follow the previous one, we
> know we can memset [unused_pmd_start, PMD_BOUNDARY) with PAGE_UNUSE.
>
> This patch is based on a similar patch by David Hildenbrand:
>
> https://lore.kernel.org/linux-mm/20200722094558.9828-10-david@redhat.com/
>
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
This is much more clear now. Thanks!
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
prev parent reply other threads:[~2021-03-09 18:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 17:41 [PATCH v5 0/4] Cleanup and fixups for vmemmap handling Oscar Salvador
2021-03-09 17:41 ` [PATCH v5 1/4] x86/vmemmap: Drop handling of 4K unaligned vmemmap range Oscar Salvador
2021-03-09 17:41 ` [PATCH v5 2/4] x86/vmemmap: Drop handling of 1GB vmemmap ranges Oscar Salvador
2021-03-09 18:34 ` Dave Hansen
2021-03-09 21:27 ` Oscar Salvador
2021-03-09 17:41 ` [PATCH v5 3/4] x86/vmemmap: Handle unpopulated sub-pmd ranges Oscar Salvador
2021-03-09 17:52 ` David Hildenbrand
2021-03-10 17:49 ` Oscar Salvador
2021-03-10 17:58 ` David Hildenbrand
2021-03-10 21:58 ` Oscar Salvador
2021-03-11 16:38 ` David Hildenbrand
2021-03-09 18:39 ` Dave Hansen
2021-03-09 17:41 ` [PATCH v5 4/4] x86/vmemmap: Optimize for consecutive sections in partial populated PMDs Oscar Salvador
2021-03-09 18:50 ` Dave Hansen [this message]
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