From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Date: Sat, 22 Aug 2009 11:18:16 +0000 Subject: Re: [Patch 5/8] ia64: implement crashkernel=auto Message-Id: <20090822111816.GA12281@elte.hu> List-Id: References: <20090821065637.4855.32234.sendpatchset@localhost.localdomain> <20090821065729.4855.47860.sendpatchset@localhost.localdomain> <20090821172407.d3a5cd2b.akpm@linux-foundation.org> In-Reply-To: <20090821172407.d3a5cd2b.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Amerigo Wang , linux-kernel@vger.kernel.org, tony.luck@intel.com, linux-ia64@vger.kernel.org, nhorman@redhat.com, ebiederm@xmission.com, andi@firstfloor.org, bernhard.walle@gmx.de, fenghua.yu@intel.com, kamezawa.hiroyu@jp.fujitsu.com, avorontsov@ru.mvista.com * Andrew Morton wrote: > On Fri, 21 Aug 2009 02:55:04 -0400 > Amerigo Wang wrote: > > > +#ifdef CONFIG_KEXEC_AUTO_RESERVE > > +#define ARCH_HAS_DEFAULT_CRASH_SIZE > > +static inline > > +unsigned long long arch_default_crash_size(unsigned long long total_size) > > +{ > > + if (total_size >= 4ULL<<30 && total_size < 12ULL<<30) > > + return 1ULL<<28; > > + else if (total_size >= 12ULL<<30 && total_size < 128ULL<<30) > > + return 1ULL<<29; > > + else if (total_size >= 128ULL<<30 && total_size < 256ULL<<30) > > + return 3ULL<<28; > > + else if (total_size >= 256ULL<<30 && total_size < 378ULL<<30) > > + return 1ULL<<30; > > + else if (total_size >= 318ULL<<30 && total_size < 512ULL<<30) > > + return 3ULL<<29; > > + else if (total_size >= 512ULL<<30 && total_size < 768ULL<<30) > > + return 2ULL<<30; > > + else if (total_size >= 768ULL<<30) > > + return 3ULL<<30; > > +} > > +#include > > +#endif > > a) Why on earth is this inlined? > > b) Please consider making arch_default_crash_size() a __weak > function. You'll probably find the result to be pleasing. > > c) If we can't use __weak then please don't add > ARCH_HAS_DEFAULT_CRASH_SIZE. Instead do this trick: > > > #ifndef arch_default_crash_size > static inline unsigned long long arch_default_crash_size(unsigned long long total_size) > { > ... > } > #define arch_default_crash_size arch_default_crash_size > #endif > > because i) it's good to standardise on something and ii) one less > symbol gets added to the kernel. > > d) why is asm-generic/kexec.h only included in asm/kexec.h if > CONFIG_KEXEC_AUTO_RESERVE happened to be defined? That makes no > sense - there may be a multitude of reasons why asm/kexec.h wants > to include asm-generic/kexec.h. e) All the 'else' statements are superflous and make it all harder to read. f) 2ULL<<30 should be written as 1ULL<31, to keep things consistent. g) A nice comment explaining the purpose and logic wouldnt hurt. Ingo