Re: memory zone and slab

Hi,

I'm not sure I understand your question.

The slab allocator groups objects into "caches".
Each cache contains objects of the _same_ type.
The area of memory that contains the cache is divided into "slabs"
and each slab consists of one or more contiguous _pages_.
If a page belongs to a slab it has the "PG_slab" page->flags bit set
(see include/linux/page-flags.h).

Pages tend to belong to a particular zone.

I hope this helps.

Kind regards,
Aaron

On Sat, Mar 9, 2013 at 2:04 AM, ishare <[email protected]> wrote:
> On Fri, Mar 08, 2013 at 11:44:37AM +0000, Mario Smarduch wrote:
>>
>> The zonelists are initialized in 'build_all_zonelists()'
>> called by 'start_kernel()'. But prior to that point
>> there is allot of other code that determines the
>> various zones and holes a key function is free_area_init_node().
>> But that function will also reference prior initialization
>> in 'setup_arch()' which may take you all the way back
>> to bootloader
>> Nodes have zones, and zones define what the memory is
>> appropriate for, DMA or lowmem, Normal memory or High memory
>> for 32 bit. For 64 bit there are fewer zones just primarily
>> 32 bit DMA and normal 64 bit. Zones are further divided
>> into free areas of 2^n consecutive pages.
>>
>> Slabs are typically pages carved up into smaller units of
>> allocations.
>
>   Does this mean slab is based on zone ?
>   slab is just a optimized algorithm for normal allocator?
>
>   thanks!
>
>
>
>
>
>> There are several kernel books but outdated, but nevertheless good
>> starting points, just search for 'Kernel Internals'
>>
>> BR,
>>  Mario.
>>
>>
>> -----Original Message-----
>> From: [email protected] [mailto:[email protected]] On Behalf Of ishare
>> Sent: Thursday, March 07, 2013 3:35 PM
>> To: [email protected]
>> Subject: memory zone and slab
>>
>>
>>    when does the memory zonelist initialized in kernel ?
>>
>>    what is the difference between zonelists and slab for memory manage .
>>
>>    are there some man docs or sites  helpful to understand this ?
>>
>>    thanks!
>>
>> --
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