On 03/29/2010 03:20 PM, Michael Ellerman wrote: > On Mon, 2010-03-29 at 09:45 -0700, Yinghai Lu wrote: >> On 03/29/2010 05:22 AM, Michael Ellerman wrote: >>> On Sun, 2010-03-28 at 19:43 -0700, Yinghai Lu wrote: >>>> They will check if the region array is big enough. >>>> >>>> __check_and_double_region_array will try to double the region if that array spare >>>> slots if not big enough. >>>> find_lmb_area() is used to find good postion for new region array. >>>> Old array will be copied to new array. >>>> >>>> Arch code should provide to get_max_mapped, so the new array have accessiable >>>> address >>> .. >>>> diff --git a/mm/lmb.c b/mm/lmb.c >>>> index d5d5dc4..9798458 100644 >>>> --- a/mm/lmb.c >>>> +++ b/mm/lmb.c >>>> @@ -551,6 +551,95 @@ int lmb_find(struct lmb_property *res) >>>> return -1; >>>> } >>>> >>>> +u64 __weak __init get_max_mapped(void) >>>> +{ >>>> + u64 end = max_low_pfn; >>>> + >>>> + end <<= PAGE_SHIFT; >>>> + >>>> + return end; >>>> +} >>> >>> ^ This is (sort of) what lmb.rmo_size represents. So maybe instead of >>> adding this function, we could just say that the arch code needs to set >>> rmo_size up with an appropriate value, and then use that below. Though >>> maybe that's conflating things. >> >> ok >> >> will have another patch following this patchset. to use rmo_size replace get_max_mapped() > > No don't, Benh's idea was better. Leave rmo_size for now, we can clean > that up later. > > We just need a lmb.alloc_limit and a lmb_set_alloc_limit() which arch > code calls when it knows what the alloc limit is (and can call multiple > times during boot). Or maybe it should be called "default_alloc_limit", > but that's getting a bit long winded. ok, I will get_max_mapped() for now, an will change to new field...later > >> >> long __init_lmb lmb_add(u64 base, u64 size) >> { >> struct lmb_region *_rgn = &lmb.memory; >> >> /* On pSeries LPAR systems, the first LMB is our RMO region. */ >> if (base == 0) >> lmb.rmo_size = size; >> >> return lmb_add_region(_rgn, base, size); >> >> } >> >> looks scary. >> maybe later powerpc could used lmb_find and set_lmb_rmo_size in their arch code. > > It's not really scary, and it gives you a hint where the code came from > originally :) > > We can remove that later though, with some powerpc code to detect the > first memory region before we put it into lmb. good. > >>> ... >>>> + >>>> +void __init add_lmb_memory(u64 start, u64 end) >>>> +{ >>>> + __check_and_double_region_array(&lmb.memory, &lmb_memory_region[0], start, end); >>>> + lmb_add(start, end - start); >>>> +} >>>> + >>>> +void __init reserve_lmb(u64 start, u64 end, char *name) >>>> +{ >>>> + if (start == end) >>>> + return; >>>> + >>>> + if (WARN_ONCE(start > end, "reserve_lmb: wrong range [%#llx, %#llx]\n", start, end)) >>>> + return; >>>> + >>>> + __check_and_double_region_array(&lmb.reserved, &lmb_reserved_region[0], start, end); >>>> + lmb_reserve(start, end - start); >>>> +} >>>> + >>>> +void __init free_lmb(u64 start, u64 end) >>>> +{ >>>> + if (start == end) >>>> + return; >>>> + >>>> + if (WARN_ONCE(start > end, "free_lmb: wrong range [%#llx, %#llx]\n", start, end)) >>>> + return; >>>> + >>>> + /* keep punching hole, could run out of slots too */ >>>> + __check_and_double_region_array(&lmb.reserved, &lmb_reserved_region[0], start, end); >>>> + lmb_free(start, end - start); >>>> +} >>> >>> Doesn't this mean that if I call lmb_alloc() or lmb_free() too many >>> times then I'll potentially run out of space? So doesn't that >>> essentially break the existing API? >> >> No, I didn't touch existing API, arches other than x86 should have little change about >> lmb.memory.region >> lmb.reserved.region >> become pointer from array. > > But that's my point. You shouldn't need to touch the existing API, and > you shouldn't need to add a new parallel API. You should just be able to > add the logic for doubling the array in the lmb core, and then everyone > gets dynamically expandable lmb. I don't see any reason why we want to > have two APIs. that will have too much change for all x86 caller. that set of API is __init, and will be freed later. and these two are just wrapper for old one to make x86 transition more easily. > >>> It seems to me that rather than adding these "special" routines that >>> check for enough space on the way in, instead you should be checking in >>> lmb_add_region() - which is where AFAICS all allocs/frees/reserves >>> eventually end up if they need to insert a new region. >> >> later i prefer to replace lmb_alloc with find_lmb_area + reserve_lmb. > > Why? The existing code has been working for years and is well tested? We need to find_lmb_area to find good position for new reserved region array. static void __init __reserve_lmb(u64 start, u64 end, char *name) { __check_and_double_region_array(&lmb.reserved, &lmb_reserved_region[0], start, end); lmb_reserve(start, end - start); } with the execlude area in __check_and_double_region_lmb() will not put the new array overlap with area that we are going to reserve. and find_lmb_area + reserve_lmb should be identical to lmb_alloc... Thanks Yinghai Lu -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html