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Date: Mon, 13 Nov 2017 17:26:24 +0800 From: Baoquan He <bhe@...hat.com> To: Chao Fan <fanc.fnst@...fujitsu.com> Cc: linux-kernel@...r.kernel.org, x86@...nel.org, hpa@...or.com, tglx@...utronix.de, mingo@...hat.com, keescook@...omium.org, yasu.isimatu@...il.com, indou.takao@...fujitsu.com, caoj.fnst@...fujitsu.com, douly.fnst@...fujitsu.com Subject: Re: [PATCH v2 2/4] kaslr: select the memory region in immovable node to process On 11/13/17 at 05:18pm, Chao Fan wrote: > On Mon, Nov 13, 2017 at 04:31:31PM +0800, Baoquan He wrote: > >On 11/01/17 at 07:32pm, Chao Fan wrote: > >> Compare the region of memmap entry and immovable_mem, then choose the > >> intersection to process_mem_region. > >> > >> Since the interrelationship between e820 or efi entries and memory > >> region in immovable_mem is different: > >> One memory region in one node may contain several entries of e820 or > >> efi sometimes, and one entry of e820 or efi may contain the memory in > >> different nodes sometimes. > >> It may split one node or one entry to several regions. > >> > >> Signed-off-by: Chao Fan <fanc.fnst@...fujitsu.com> > >> --- > >> arch/x86/boot/compressed/kaslr.c | 60 ++++++++++++++++++++++++++++++++++------ > >> 1 file changed, 52 insertions(+), 8 deletions(-) > >> > >> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > >> index 0a591c0023f1..fcd640fdeaed 100644 > >> --- a/arch/x86/boot/compressed/kaslr.c > >> +++ b/arch/x86/boot/compressed/kaslr.c > >> @@ -634,6 +634,54 @@ static void process_mem_region(struct mem_vector *entry, > >> } > >> } > >> > >> +static bool select_immovable_node(struct mem_vector region, > >> + unsigned long long minimum, > >> + unsigned long long image_size) > >> +{ > > > >About this patch, I just want to notice two things: > >1) From the current code, 'movable_node' kernel parameter is exclusive. > >In find_zone_movable_pfns_for_nodes(), you can see that 'kernelcore' and > >'movablecore' will be ignored as long as 'movable_node' is specified. > >Please also consider this in your code here. If 'movable_node' has to be > >specified too, and need skip the kernel mirror handling. > > > > Thanks for the notice, I will add the similar operation. No, I meant if movable_node is specified, we have to ignore 'kernelcore=', then we may need skip the kernel mirror handling. Since kernel mirror is enabled by 'kernelcore=mirror'. > > >2)process_mem_region() is a key function to process the available memory > >regions. Please don't make another process_mem_region() like below. You > >can write a small helper function to find the immovable_mem[] which is > >intersecting with the passed in memory region and use clamp() to get > >the real available region. You 'REALLY' don't need to split the region > >in your so called 'select_immovable_node()' function here. > > > > OK, I will try to make a new method, which is smaller and better to > filter the regions. > > Thanks, > Chao Fan > > >PLEASE elaborate more on these details before post. > > > >Thanks > >Baoquan > > > >> + int i; > >> + > >> + /* If no immovable_mem stored, use region directly */ > >> + if (num_immovable_region == 0) { > >> + process_mem_region(®ion, minimum, image_size); > >> + > >> + if (slot_area_index == MAX_SLOT_AREA) { > >> + debug_putstr("Aborted memmap scan (slot_areas full)!\n"); > >> + return 1; > >> + } > >> + } else { > >> + /* > >> + * Walk all immovable regions, and filter the intersection > >> + * to process_mem_region. > >> + */ > >> + for (i = 0; i < num_immovable_region; i++) { > >> + struct mem_vector entry; > >> + unsigned long long start, end, select_end, region_end; > >> + > >> + region_end = region.start + region.size - 1; > >> + start = immovable_mem[i].start; > >> + end = start + immovable_mem[i].size - 1; > >> + > >> + if (region_end < start || region.start > end) > >> + continue; > >> + > >> + /* May split one region to several entries. */ > >> + entry.start = start > region.start ? > >> + start : region.start; > >> + select_end = end > region_end ? region_end : end; > >> + > >> + entry.size = select_end - entry.start + 1; > >> + > >> + process_mem_region(&entry, minimum, image_size); > >> + > >> + if (slot_area_index == MAX_SLOT_AREA) { > >> + debug_putstr("Aborted memmap scan (slot_areas full)!\n"); > >> + return 1; > >> + } > >> + } > >> + } > >> + return 0; > >> +} > >> + > >> #ifdef CONFIG_EFI > >> /* > >> * Returns true if mirror region found (and must have been processed > >> @@ -699,11 +747,9 @@ process_efi_entries(unsigned long minimum, unsigned long image_size) > >> > >> region.start = md->phys_addr; > >> region.size = md->num_pages << EFI_PAGE_SHIFT; > >> - process_mem_region(®ion, minimum, image_size); > >> - if (slot_area_index == MAX_SLOT_AREA) { > >> - debug_putstr("Aborted EFI scan (slot_areas full)!\n"); > >> + > >> + if (select_immovable_node(region, minimum, image_size)) > >> break; > >> - } > >> } > >> return true; > >> } > >> @@ -730,11 +776,9 @@ static void process_e820_entries(unsigned long minimum, > >> continue; > >> region.start = entry->addr; > >> region.size = entry->size; > >> - process_mem_region(®ion, minimum, image_size); > >> - if (slot_area_index == MAX_SLOT_AREA) { > >> - debug_putstr("Aborted e820 scan (slot_areas full)!\n"); > >> + > >> + if (select_immovable_node(region, minimum, image_size)) > >> break; > >> - } > >> } > >> } > >> > >> -- > >> 2.13.6 > >> > >> > >> > > > > > >
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