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 v4 3/3] x86/vmemmap: Handle unpopulated sub-pmd ranges
Date: Thu, 4 Mar 2021 09:08:37 -0800 [thread overview]
Message-ID: <3d49fdca-de12-aa7d-ffc4-b2a8c7d79bee@intel.com> (raw)
In-Reply-To: <b1aff368-8321-0fa7-05ab-3d6c856c00f8@intel.com>
On 3/4/21 9:02 AM, Dave Hansen wrote:
>> +#define PAGE_UNUSED 0xFD
>> +/*
>> + * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
>> + * from unused_pmd_start to next PMD_SIZE boundary.
>> + */
>> +static unsigned long unused_pmd_start __meminitdata;
> This whole 'unused_pmd_start' thing was unmentioned in the changelog.
One tiny suggestion: *Sometimes* for these optimizations, it's easiest
to write the code up without it in one patch, then add the optimization
in the next patch.
It makes it 100% clear what is part of the "core" algorithm and what is
pure optimization.
I don't know if it will work here, but it might be worth taking a look.
next prev parent reply other threads:[~2021-03-05 17:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 8:32 [PATCH v4 0/3] Cleanup and fixups for vmemmap handling Oscar Salvador
2021-03-01 8:32 ` [PATCH v4 1/3] x86/vmemmap: Drop handling of 4K unaligned vmemmap range Oscar Salvador
2021-03-04 15:50 ` Dave Hansen
2021-03-08 18:20 ` Oscar Salvador
2021-03-08 18:26 ` Dave Hansen
2021-03-01 8:32 ` [PATCH v4 2/3] x86/vmemmap: Drop handling of 1GB vmemmap ranges Oscar Salvador
2021-03-04 18:42 ` Dave Hansen
2021-03-08 18:48 ` Oscar Salvador
2021-03-08 19:25 ` David Hildenbrand
2021-03-01 8:32 ` [PATCH v4 3/3] x86/vmemmap: Handle unpopulated sub-pmd ranges Oscar Salvador
2021-03-04 17:02 ` Dave Hansen
2021-03-04 17:08 ` Dave Hansen [this message]
2021-03-05 18:26 ` David Hildenbrand
2021-03-08 18:43 ` Oscar Salvador
2021-03-09 8:25 ` Oscar Salvador
2021-03-09 14:50 ` Dave Hansen
2021-03-09 19:39 ` Zi Yan
2021-03-09 21:26 ` Oscar Salvador
2021-03-03 0:09 ` [PATCH v4 0/3] Cleanup and fixups for vmemmap handling Andrew Morton
2021-03-03 18:38 ` Borislav Petkov
2021-03-03 23:04 ` Andrew Morton
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