%Memory
%Thadeu Cascardo

# Memory

* Real (Physical) Address
* Virtual Address
* Bus Address
* Linear Address

# Memory Zones

* Normal Zone
* DMA Zone
* High Memory Zone

# Flags

* GFP\\_KERNEL
* GFP\\_ATOMIC
* GFP\\_USER
* GFP\\_HIGHUSER
* GFP\\_NOFS
* GFP\\_NOIO
* \\_\\_GFP\\_ZERO
* \\_\\_GFP\\_DMA
* \\_\\_GFP\\_HIGHMEM
* \\_\\_GFP\\_NOWARN
* \\_\\_GFP\\_REPEAT
* \\_\\_GFP\\_NOFAIL
* \\_\\_GFP\\_NORETRY

# Slab (lookaside cache)

* include linux/slab.h
* struct kmem\\_cache
* kmem\\_cache\\_create(name, size, offset, flags, constructor);
* kmem\\_cache\\_destroy(kmc)
* kmem\\_cache\\_alloc(kmc, gfp)
* kmem\\_cache\\_free(kmc, ptr)

# vmalloc

* Virtual memory with many pages allocated not linearly in the physical space
* Mapped in a different address range
* include linux/vmalloc.h
* vmalloc(size)
* vfree(addr)

# GFP

* \\_\\_get\\_free\\_page(flags)
* \\_\\_get\\_free\\_pages(flags, order)
* free\\_page(addr)
* free\\_pages(addr, order)
* get\\_order

# Page

* struct page
* alloc\\_pages(flags, order)
* alloc\\_page(flags)
* \\_\\_free\\_page(page)
* \\_\\_free\\_pages(page, order)