Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756569Ab2JEO6a (ORCPT ); Fri, 5 Oct 2012 10:58:30 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:36145 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756259Ab2JEO6Z (ORCPT ); Fri, 5 Oct 2012 10:58:25 -0400 MIME-Version: 1.0 In-Reply-To: References: <1348991844-12285-1-git-send-email-yinghai@kernel.org> <1348991844-12285-5-git-send-email-yinghai@kernel.org> <20121004164551.GA2244@phenom.dumpdata.com> <506E029E.3000102@zytor.com> <506E059B.40808@zytor.com> Date: Fri, 5 Oct 2012 07:58:22 -0700 X-Google-Sender-Auth: fAiyNmFMc_vtPaUD2-kCOHbMUho Message-ID: Subject: Re: [PATCH 04/13] x86, mm: Revert back good_end setting for 64bit From: Yinghai Lu To: Stefano Stabellini Cc: "H. Peter Anvin" , Konrad Rzeszutek Wilk , Thomas Gleixner , Ingo Molnar , Jacob Shin , Tejun Heo , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6667 Lines: 180 On Fri, Oct 5, 2012 at 4:27 AM, Stefano Stabellini wrote: > On Fri, 5 Oct 2012, Yinghai Lu wrote: >> On Thu, Oct 4, 2012 at 2:54 PM, H. Peter Anvin wrote: >> > >> > See my other post. This is bringing up the Kernel Summit algorithm again. >> > >> >> sure. please check if you are ok with attached one on top of x86/mm2 >> >> Subject: [PATCH] x86: get early page table from BRK >> >> set pgt_buf early from BRK, and use it to map page table at first. >> >> also use the left at first, then use new extend one. >> >> Signed-off-by: Yinghai Lu > > If I read the patch correctly, it wouldn't actually change the pagetable > allocation flow or implement Peter's suggestion. > However it would pre-map (pgt_buf_start-pgt_buf_top) using brk memory. > > So, if that's correct, we could remove the early_memremap call from > alloc_low_page and map_low_page, right? > > Also the patch introduces an additional range of pagetable pages > (early_pgt_buf_start-early_pgt_buf_top) and that would need to be > communicated somehow to Xen (that at the moment assumes that the range > is pgt_buf_start-pgt_buf_top. Pretty bad). that will need extra two lines for xen: @@ -430,6 +439,8 @@ void __init init_mem_mapping(void) x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start), PFN_PHYS(pgt_buf_end)); } + x86_init.mapping.pagetable_reserve(PFN_PHYS(early_pgt_buf_start), + PFN_PHYS(early_pgt_buf_end)); /* stop the wrong using */ pgt_buf_top = 0; > > Overall I still prefer Peter's suggestion :) > > >> --- >> arch/x86/include/asm/init.h | 4 ++++ >> arch/x86/include/asm/pgtable.h | 1 + >> arch/x86/kernel/setup.c | 2 ++ >> arch/x86/mm/init.c | 23 +++++++++++++++++++++++ >> arch/x86/mm/init_32.c | 8 ++++++-- >> arch/x86/mm/init_64.c | 8 ++++++-- >> 6 files changed, 42 insertions(+), 4 deletions(-) >> >> Index: linux-2.6/arch/x86/include/asm/pgtable.h >> =================================================================== >> --- linux-2.6.orig/arch/x86/include/asm/pgtable.h >> +++ linux-2.6/arch/x86/include/asm/pgtable.h >> @@ -599,6 +599,7 @@ static inline int pgd_none(pgd_t pgd) >> >> extern int direct_gbpages; >> void init_mem_mapping(void); >> +void early_alloc_pgt_buf(void); >> >> /* local pte updates need not use xchg for locking */ >> static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep) >> Index: linux-2.6/arch/x86/kernel/setup.c >> =================================================================== >> --- linux-2.6.orig/arch/x86/kernel/setup.c >> +++ linux-2.6/arch/x86/kernel/setup.c >> @@ -950,6 +950,8 @@ void __init setup_arch(char **cmdline_p) >> >> reserve_ibft_region(); >> >> + early_alloc_pgt_buf(); >> + >> /* >> * Need to conclude brk, before memblock_x86_fill() >> * it could use memblock_find_in_range, could overlap with >> Index: linux-2.6/arch/x86/mm/init.c >> =================================================================== >> --- linux-2.6.orig/arch/x86/mm/init.c >> +++ linux-2.6/arch/x86/mm/init.c >> @@ -21,6 +21,10 @@ unsigned long __initdata pgt_buf_start; >> unsigned long __meminitdata pgt_buf_end; >> unsigned long __meminitdata pgt_buf_top; >> >> +unsigned long __initdata early_pgt_buf_start; >> +unsigned long __meminitdata early_pgt_buf_end; >> +unsigned long __meminitdata early_pgt_buf_top; >> + >> int after_bootmem; >> >> int direct_gbpages >> @@ -291,6 +295,11 @@ static void __init find_early_table_spac >> if (!base) >> panic("Cannot find space for the kernel page tables"); >> >> + init_memory_mapping(base, base + tables); >> + printk(KERN_DEBUG "kernel direct mapping tables from %#llx to %#llx @ [mem %#010lx-%#010lx]\n", >> + base, base + tables - 1, early_pgt_buf_start << PAGE_SHIFT, >> + (early_pgt_buf_end << PAGE_SHIFT) - 1); >> + >> pgt_buf_start = base >> PAGE_SHIFT; >> pgt_buf_end = pgt_buf_start; >> pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT); >> @@ -437,6 +446,20 @@ void __init init_mem_mapping(void) >> early_memtest(0, max_pfn_mapped << PAGE_SHIFT); >> } >> >> +RESERVE_BRK(early_pgt_alloc, 16384); >> + >> +void __init early_alloc_pgt_buf(void) >> +{ >> + unsigned long tables = 13864; >> + phys_addr_t base; >> + >> + base = __pa(extend_brk(tables, PAGE_SIZE)); >> + >> + early_pgt_buf_start = base >> PAGE_SHIFT; >> + early_pgt_buf_end = early_pgt_buf_start; >> + early_pgt_buf_top = early_pgt_buf_start + (tables >> PAGE_SHIFT); >> +} >> + >> /* >> * devmem_is_allowed() checks to see if /dev/mem access to a certain address >> * is valid. The argument is a physical page number. >> Index: linux-2.6/arch/x86/mm/init_32.c >> =================================================================== >> --- linux-2.6.orig/arch/x86/mm/init_32.c >> +++ linux-2.6/arch/x86/mm/init_32.c >> @@ -61,10 +61,14 @@ bool __read_mostly __vmalloc_start_set = >> >> static __init void *alloc_low_page(void) >> { >> - unsigned long pfn = pgt_buf_end++; >> + unsigned long pfn; >> void *adr; >> >> - if (pfn >= pgt_buf_top) >> + if (early_pgt_buf_end < early_pgt_buf_top) >> + pfn = early_pgt_buf_end++; >> + else if (pgt_buf_end < pgt_buf_top) >> + pfn = pgt_buf_end++; >> + else >> panic("alloc_low_page: ran out of memory"); >> >> adr = __va(pfn * PAGE_SIZE); >> Index: linux-2.6/arch/x86/mm/init_64.c >> =================================================================== >> --- linux-2.6.orig/arch/x86/mm/init_64.c >> +++ linux-2.6/arch/x86/mm/init_64.c >> @@ -318,7 +318,7 @@ void __init cleanup_highmap(void) >> >> static __ref void *alloc_low_page(unsigned long *phys) >> { >> - unsigned long pfn = pgt_buf_end++; >> + unsigned long pfn; >> void *adr; >> >> if (after_bootmem) { >> @@ -328,7 +328,11 @@ static __ref void *alloc_low_page(unsign >> return adr; >> } >> >> - if (pfn >= pgt_buf_top) >> + if (early_pgt_buf_end < early_pgt_buf_top) >> + pfn = early_pgt_buf_end++; >> + else if (pgt_buf_end < pgt_buf_top) >> + pfn = pgt_buf_end++; >> + else >> panic("alloc_low_page: ran out of memory"); >> >> adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/