Messages in this thread | | | Subject | Re: [PATCH] memblock: Don't adjust size in memblock_find_base() | From | Benjamin Herrenschmidt <> | Date | Mon, 10 Jan 2011 16:56:29 +1100 |
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On Fri, 2011-01-07 at 12:41 -0800, Yinghai Lu wrote: > While applying patch to use memblock to find aperture for 64bit x86. > Ingo found system with 1g + force_iommu
Please run that through DaveM. I seem to remember that he relies on the size alignment to ensure that a lot of tiny allocations get properly coalesced or he runs out of regions at boot time.
A better option would be to use a fixed alignment, or sized based but with a max threshold such as PAGE_SIZE.
Cheers, Ben.
> > No AGP bridge found > > Node 0: aperture @ 38000000 size 32 MB > > Aperture pointing to e820 RAM. Ignoring. > > Your BIOS doesn't leave a aperture memory hole > > Please enable the IOMMU option in the BIOS setup > > This costs you 64 MB of RAM > > Cannot allocate aperture memory hole (0,65536K) > > the corresponding code: > addr = memblock_find_in_range(0, 1ULL<<32, aper_size, 512ULL<<20); > if (addr == MEMBLOCK_ERROR || addr + aper_size > 0xffffffff) { > printk(KERN_ERR > "Cannot allocate aperture memory hole (%lx,%uK)\n", > addr, aper_size>>10); > return 0; > } > memblock_x86_reserve_range(addr, addr + aper_size, "aperture64") > > it fails because memblock core code align the size with 512M. that could make > size way too big. > > So don't align the size in that case. > > actually __memblock_alloc_base, the another caller already align that before calling that function. > > BTW. x86 does not use __memblock_alloc_base... > > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > > --- > mm/memblock.c | 2 -- > 1 file changed, 2 deletions(-) > > Index: linux-2.6/mm/memblock.c > =================================================================== > --- linux-2.6.orig/mm/memblock.c > +++ linux-2.6/mm/memblock.c > @@ -137,8 +137,6 @@ static phys_addr_t __init_memblock membl > > BUG_ON(0 == size); > > - size = memblock_align_up(size, align); > - > /* Pump up max_addr */ > if (end == MEMBLOCK_ALLOC_ACCESSIBLE) > end = memblock.current_limit; > -- > 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/
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