From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 23 Apr 2020 08:55:59 +0300 From: Mike Rapoport Subject: Re: [PATCH 17/21] mm: free_area_init: allow defining max_zone_pfn in descending order Message-ID: <20200423055559.GF14260@kernel.org> References: <20200412194859.12663-1-rppt@kernel.org> <20200412194859.12663-18-rppt@kernel.org> <20200423025311.GZ4247@MiWiFi-R3L-srv> <20200423025720.GA4247@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200423025720.GA4247@MiWiFi-R3L-srv> Sender: owner-linux-mm@kvack.org To: Baoquan He Cc: linux-kernel@vger.kernel.org, Andrew Morton , Brian Cain , Catalin Marinas , "David S. Miller" , Geert Uytterhoeven , Greentime Hu , Greg Ungerer , Guan Xuetao , Guo Ren , Heiko Carstens , Helge Deller , Hoan Tran , "James E.J. Bottomley" , Jonathan Corbet , Ley Foon Tan , Mark Salter , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Nick Hu , Paul Walmsley , Richard Weinberger , Rich Felker , Russell King , Stafford Horne , Thomas Bogendoerfer , Tony Luck , Vineet Gupta , x86@kernel.org, Yoshinori Sato , linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org, linux-csky@vger.kernel.org, linux-doc@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, openrisc@lists.librecores.org, sparclinux@vger.kernel.org, uclinux-h8-devel@lists.sourceforge.jp, Mike Rapoport List-ID: Message-ID: <20200423055559._QiIGM73B1kuqOlOlz_3tXnv2nx73ic6cUseH6eJ3W0@z> On Thu, Apr 23, 2020 at 10:57:20AM +0800, Baoquan He wrote: > On 04/23/20 at 10:53am, Baoquan He wrote: > > On 04/12/20 at 10:48pm, Mike Rapoport wrote: > > > From: Mike Rapoport > > > > > > Some architectures (e.g. ARC) have the ZONE_HIGHMEM zone below the > > > ZONE_NORMAL. Allowing free_area_init() parse max_zone_pfn array even it is > > > sorted in descending order allows using free_area_init() on such > > > architectures. > > > > > > Add top -> down traversal of max_zone_pfn array in free_area_init() and use > > > the latter in ARC node/zone initialization. > > > > Or maybe leave ARC as is. The change in this patchset doesn't impact > > ARC's handling about zone initialization, leaving it as is can reduce > > the complication in implementation of free_area_init(), which is a > > common function. So I personally don't see a strong motivation to have > > this patch. > > OK, seems this patch is prepared to simplify free_area_init_node(), so > take back what I said at above. > > Then this looks necessary, even though it introduces special case into > common function free_area_init(). The idea is to have a single free_area_init() for all architectures without keeping two completely different ways of calculating the zone extents. Another thing, is that with this we could eventually switch ARC from DISCONTIGMEM. > Reviewed-by: Baoquan He > > > > > > > > > Signed-off-by: Mike Rapoport > > > --- > > > arch/arc/mm/init.c | 36 +++++++----------------------------- > > > mm/page_alloc.c | 24 +++++++++++++++++++----- > > > 2 files changed, 26 insertions(+), 34 deletions(-) > > > > > > diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c > > > index 0920c969c466..41eb9be1653c 100644 > > > --- a/arch/arc/mm/init.c > > > +++ b/arch/arc/mm/init.c > > > @@ -63,11 +63,13 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size) > > > > > > low_mem_sz = size; > > > in_use = 1; > > > + memblock_add_node(base, size, 0); > > > } else { > > > #ifdef CONFIG_HIGHMEM > > > high_mem_start = base; > > > high_mem_sz = size; > > > in_use = 1; > > > + memblock_add_node(base, size, 1); > > > #endif > > > } > > > > > > @@ -83,8 +85,7 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size) > > > */ > > > void __init setup_arch_memory(void) > > > { > > > - unsigned long zones_size[MAX_NR_ZONES]; > > > - unsigned long zones_holes[MAX_NR_ZONES]; > > > + unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; > > > > > > init_mm.start_code = (unsigned long)_text; > > > init_mm.end_code = (unsigned long)_etext; > > > @@ -115,7 +116,6 @@ void __init setup_arch_memory(void) > > > * the crash > > > */ > > > > > > - memblock_add_node(low_mem_start, low_mem_sz, 0); > > > memblock_reserve(CONFIG_LINUX_LINK_BASE, > > > __pa(_end) - CONFIG_LINUX_LINK_BASE); > > > > > > @@ -133,22 +133,7 @@ void __init setup_arch_memory(void) > > > memblock_dump_all(); > > > > > > /*----------------- node/zones setup --------------------------*/ > > > - memset(zones_size, 0, sizeof(zones_size)); > > > - memset(zones_holes, 0, sizeof(zones_holes)); > > > - > > > - zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn; > > > - zones_holes[ZONE_NORMAL] = 0; > > > - > > > - /* > > > - * We can't use the helper free_area_init(zones[]) because it uses > > > - * PAGE_OFFSET to compute the @min_low_pfn which would be wrong > > > - * when our kernel doesn't start at PAGE_OFFSET, i.e. > > > - * PAGE_OFFSET != CONFIG_LINUX_RAM_BASE > > > - */ > > > - free_area_init_node(0, /* node-id */ > > > - zones_size, /* num pages per zone */ > > > - min_low_pfn, /* first pfn of node */ > > > - zones_holes); /* holes */ > > > + max_zone_pfn[ZONE_NORMAL] = max_low_pfn; > > > > > > #ifdef CONFIG_HIGHMEM > > > /* > > > @@ -168,20 +153,13 @@ void __init setup_arch_memory(void) > > > min_high_pfn = PFN_DOWN(high_mem_start); > > > max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz); > > > > > > - zones_size[ZONE_NORMAL] = 0; > > > - zones_holes[ZONE_NORMAL] = 0; > > > - > > > - zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn; > > > - zones_holes[ZONE_HIGHMEM] = 0; > > > - > > > - free_area_init_node(1, /* node-id */ > > > - zones_size, /* num pages per zone */ > > > - min_high_pfn, /* first pfn of node */ > > > - zones_holes); /* holes */ > > > + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn; > > > > > > high_memory = (void *)(min_high_pfn << PAGE_SHIFT); > > > kmap_init(); > > > #endif > > > + > > > + free_area_init(max_zone_pfn); > > > } > > > > > > /* > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > > index 343d87b8697d..376434c7a78b 100644 > > > --- a/mm/page_alloc.c > > > +++ b/mm/page_alloc.c > > > @@ -7429,7 +7429,8 @@ static void check_for_memory(pg_data_t *pgdat, int nid) > > > void __init free_area_init(unsigned long *max_zone_pfn) > > > { > > > unsigned long start_pfn, end_pfn; > > > - int i, nid; > > > + int i, nid, zone; > > > + bool descending = false; > > > > > > /* Record where the zone boundaries are */ > > > memset(arch_zone_lowest_possible_pfn, 0, > > > @@ -7439,13 +7440,26 @@ void __init free_area_init(unsigned long *max_zone_pfn) > > > > > > start_pfn = find_min_pfn_with_active_regions(); > > > > > > + /* > > > + * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below > > > + * ZONE_NORMAL. For such cases we allow max_zone_pfn sorted in the > > > + * descending order > > > + */ > > > + if (MAX_NR_ZONES > 1 && max_zone_pfn[0] > max_zone_pfn[1]) > > > + descending = true; > > > + > > > for (i = 0; i < MAX_NR_ZONES; i++) { > > > - if (i == ZONE_MOVABLE) > > > + if (descending) > > > + zone = MAX_NR_ZONES - i - 1; > > > + else > > > + zone = i; > > > + > > > + if (zone == ZONE_MOVABLE) > > > continue; > > > > > > - end_pfn = max(max_zone_pfn[i], start_pfn); > > > - arch_zone_lowest_possible_pfn[i] = start_pfn; > > > - arch_zone_highest_possible_pfn[i] = end_pfn; > > > + end_pfn = max(max_zone_pfn[zone], start_pfn); > > > + arch_zone_lowest_possible_pfn[zone] = start_pfn; > > > + arch_zone_highest_possible_pfn[zone] = end_pfn; > > > > > > start_pfn = end_pfn; > > > } > > > -- > > > 2.25.1 > > > > -- Sincerely yours, Mike.