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temp. mem mappings

DISCUSSION cohutta 2 participants 2 messages Jun 11, 2001 – Jun 25, 2001 Memory management

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#0 lore raw
Quoted 14 lines

===== Original Message From "Joseph A. Knapka" <[email protected]> =====

Quoted 12 lines · Stephen C. Tweedie

Hi,

Quoted 6 lines · cohutta
Quoted 2 lines

Right --- you can use alloc_pages but we haven't done the initialisation of the kmalloc slabsl by this point.

My testing indicates that i can't use __get_free_page(GFP_KERNEL) any time during setup_arch() [still x86]. It causes a BUG in slab.c (line 920) [linux 2.4.5].

Quoted 6 lines
Quoted 3 lines

After paging_init(), it should be OK --- as long as there is enough memory that you don't end up calling the VM try_to_free_page routines. Those will definitely choke this early in boot.

But we don't actually give the zone allocator any free pages until mem_init().

Right, so what Stephen warned about is happening:
__get_free_page() causes a BUG in slab.c via __alloc_pages() -> try_to_free_pages() -> do_try_to_free_pages() -> shrink_dcache_memory() -> kmem_cache_shrink() -> BUG().

/c/

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#1 lore raw

I don't know if this has been resolved but I believe the correct idiom to read the ACPI table would be:
kmap(virt_to_page(phys_to_virt(address)));

And then kunmap it when you are done.

Eric

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