RE: kernel memory allocations alignment

From: Hen, Shmulik (
Date: Sun Feb 04 2001 - 11:15:39 EST

Actually yes. We were warned that on IA64 architecture the system will halt
when accessing any type of variable via a pointer if the pointer does not
contain an aligned address matching that type. Until now we were using a
method of receiving a pointer to an array, casting it to a pointer of a
struct (packed with #pragma pack(1) ) ,and retrieving fields directly from
it with pointers.
It seems we cannot do that any more and were wondering what are the
One way we could think of is forget the packing and rearrange the fields in
the struct in descending order so they all come out aligned, but we didn't
know for sure if the first one will be aligned too.

Will that work ?

        Shmulik Hen
      Software Engineer
        Linux Advanced Networking Services
        Intel Network Communications Group
        Jerusalem, Israel

-----Original Message-----
From: Manfred []
Sent: Sunday, February 04, 2001 5:56 PM
To: Hen, Shmulik
Cc: 'LKML'
Subject: Re: kernel memory allocations alignment

"Hen, Shmulik" wrote:
> When using kmalloc(size_t size), do I get a guaranty that the memory
> allocated is aligned according to the size specified ?
> More to the point, if I call kmalloc for type int on an IA64 architecture
> the pointer going to be 8 bytes aligned ?

Yes, kmalloc results are always 'sizeof(void*)' aligned.

Do you have stricter alignment requirements?


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