From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Date: Thu, 13 Aug 2020 22:21:10 +0000 Subject: Re: [PATCH v5] arch/ia64: Restore arch-specific pgd_offset_k implementation Message-Id: <20200813222110.GE752365@kernel.org> List-Id: References: <20200813205521.5405-1-rppt@kernel.org> <20200813213631.GQ17456@casper.infradead.org> In-Reply-To: <20200813213631.GQ17456@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Matthew Wilcox Cc: Jessica Clarke , John Paul Adrian Glaubitz , Tony Luck , linux-ia64@vger.kernel.org, Anatoly Pugachev , Sergei Trofimovich , linux-mm@kvack.org, Frank Scheiner , Mike Rapoport On Thu, Aug 13, 2020 at 10:36:31PM +0100, Matthew Wilcox wrote: > On Thu, Aug 13, 2020 at 11:55:21PM +0300, Mike Rapoport wrote: > > +/* > > + * In the kernel's mapped region we know everything is in region number 5, so > > + * as an optimisation its PGD already points to the area for that region. > > Is it actually an optimisation? Are there any benchmarks where this > makes any difference whatsoever? Or should the comment be closer to > > /* ia64 is gratuitously different. Cope with it. */ It better suits arch/ia64/Kconfig ;-) diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 5b4ec80bf586..205cdb91a6d5 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -62,6 +62,7 @@ config IA64 the 32-bit X86 line. The IA-64 Linux project has a home page at and a mailing list at . + IA-64 is gratuitously different. Cope with it. > I might suggest that pgd be changed to be the same as every other pgd > in the system, and every other architecture. I did some grepping and got lost in IA-64 assembly, so I agree with Jessica that it would open a can of worms. -- Sincerely yours, Mike.