From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 Jun 2008 10:01:31 +0200 From: Ingo Molnar Subject: Re: [PATCH] kernel parameter vmalloc size fix Message-ID: <20080616080131.GC25632@elte.hu> References: <20080616042528.GA3003@darkstar.te-china.tietoenator.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080616042528.GA3003@darkstar.te-china.tietoenator.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Young Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, hpa@zytor.com, the arch/x86 maintainers List-ID: * Dave Young wrote: > booting kernel with vmalloc=[any size<=16m] will oops. > > It's due to the vm area hole. > > In include/asm-x86/pgtable_32.h: > #define VMALLOC_OFFSET (8 * 1024 * 1024) > #define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \ > & ~(VMALLOC_OFFSET - 1)) > > BUG_ON in arch/x86/mm/init_32.c will be triggered: > BUG_ON((unsigned long)high_memory > VMALLOC_START); > > Fixed by return -EINVAL for invalid parameter hm. Why dont we instead add the size of the hole to the __VMALLOC_RESERVE value instead? There's nothing inherently bad about using vmalloc=16m. The VM area hole is really a kernel-internal abstraction that should not be visible in the usage of the parameter. Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org