> Given the above, some basic suggestions for page-based memory management:
>
> (a) If you need to allocate or free a single page, use the single page
> version of the routine/macro, rather than calling the multi-page
> version with an order value of zero, such as:
>
> alloc_pages(gfp_mask, 0); /* no */
> alloc_page(gfp_mask); /* better */
>
> (b) If you need to allocate a single zeroed page by logical address,
> use get_zeroed_page(), rather than __get_free_page() followed
> by a call to memset() to clear that page.
both look good... I'd be in favor of this.
Maybe also add a part about using GFP_KERNEL whenever possible, GFP_NOFS
from filesystem writeout code and GFP_NOIO from block writeout code
(and never doing in_interrupt()?GFP_ATOMIC:GFP_KERNEL !)
>
> (c) If you need to specifically allocate some DMA pages, use the
> __get_dma_pages() macro, as in:
>
> __get_free_pages(GFP_KERNEL|GFP_DMA, order) /* no */
> __get_dma_pages(GFP_KERNEL, order) /* better */
this.. does not really. GFP_DMA is an ancient artifact from the ISA
days. Better to describe the dma mapping interface (well give a pointer
to the doc that already exists about that), that one is REALLY for
allocating dma pages in this century.
--
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