Messages in this thread | | | Subject | Re: [PATCH 17/35] x86, lmb: Add x86 version of __lmb_find_area() | From | Benjamin Herrenschmidt <> | Date | Fri, 14 May 2010 12:34:26 +1000 |
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On Thu, 2010-05-13 at 17:19 -0700, Yinghai Lu wrote: > Generic version is going from high to low, and it seems it can not find > right area compact enough. > > the x86 version will go from goal to limit and just like the way We used > for early_res > > use ARCH_FIND_LMB_AREA to select from them.
Why the heck ?
So LMB is designed to work top->down and now you replace lmb_find_area() with a -completely different- implementation that goes bottom->up without any explanation as to why you are doing so ?
top->down tend to be move efficient at keeping things less fragmented btw.
Cheers, Ben.
> -v2: default to no > > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > --- > arch/x86/Kconfig | 8 +++++ > arch/x86/mm/lmb.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 86 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index d80d2ab..36a5665 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -584,6 +584,14 @@ config PARAVIRT_DEBUG > Enable to debug paravirt_ops internals. Specifically, BUG if > a paravirt_op is missing when it is called. > > +config ARCH_LMB_FIND_AREA > + default n > + bool "Use x86 own lmb_find_area()" > + ---help--- > + Use lmb_find_area() version instead of generic version, it get free > + area up from low. > + Generic one try to get free area down from limit. > + > config NO_BOOTMEM > default y > bool "Disable Bootmem code" > diff --git a/arch/x86/mm/lmb.c b/arch/x86/mm/lmb.c > index c0c4220..cf9d488 100644 > --- a/arch/x86/mm/lmb.c > +++ b/arch/x86/mm/lmb.c > @@ -435,3 +435,81 @@ u64 __init lmb_hole_size(u64 start, u64 end) > return end - start - ((u64)ram << PAGE_SHIFT); > } > > +#ifdef CONFIG_ARCH_LMB_FIND_AREA > +static int __init find_overlapped_early(u64 start, u64 end) > +{ > + int i; > + struct lmb_region *r; > + > + for (i = 0; i < lmb.reserved.cnt && lmb.reserved.regions[i].size; i++) { > + r = &lmb.reserved.regions[i]; > + if (end > r->base && start < (r->base + r->size)) > + break; > + } > + > + return i; > +} > + > +/* Check for already reserved areas */ > +static inline bool __init bad_addr(u64 *addrp, u64 size, u64 align) > +{ > + int i; > + u64 addr = *addrp; > + bool changed = false; > + struct lmb_region *r; > +again: > + i = find_overlapped_early(addr, addr + size); > + r = &lmb.reserved.regions[i]; > + if (i < lmb.reserved.cnt && r->size) { > + *addrp = addr = round_up(r->base + r->size, align); > + changed = true; > + goto again; > + } > + return changed; > +} > + > +u64 __init __lmb_find_area(u64 ei_start, u64 ei_last, u64 start, u64 end, > + u64 size, u64 align) > +{ > + u64 addr, last; > + > + addr = round_up(ei_start, align); > + if (addr < start) > + addr = round_up(start, align); > + if (addr >= ei_last) > + goto out; > + while (bad_addr(&addr, size, align) && addr+size <= ei_last) > + ; > + last = addr + size; > + if (last > ei_last) > + goto out; > + if (last > end) > + goto out; > + > + return addr; > + > +out: > + return LMB_ERROR; > +} > + > +/* > + * Find a free area with specified alignment in a specific range. > + */ > +u64 __init lmb_find_area(u64 start, u64 end, u64 size, u64 align) > +{ > + int i; > + > + for (i = 0; i < lmb.memory.cnt; i++) { > + u64 ei_start = lmb.memory.regions[i].base; > + u64 ei_last = ei_start + lmb.memory.regions[i].size; > + u64 addr; > + > + addr = __lmb_find_area(ei_start, ei_last, start, end, > + size, align); > + > + if (addr != LMB_ERROR) > + return addr; > + } > + return LMB_ERROR; > +} > +#endif
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