Zach Brown wrote:
I need to keep 'struct chunk' as small as possible. This 'test_bit'
usage is
just super blind copying of page-flags.h :)
I think this should do (atomic guarantee not required):
Oh, if you don't need atomicity why not just use a bitfield?
unsigned short free:1,
size:15;
or whatever. Though I think you'll find that most archs are padding it
out to be at least an int anyway to avoid unaligned accesses of
neighbouring members.
Never used 'bitfield' before. I'll surely look into this.
I couldn't find equivalent error codes with meaning of CC_EEXPAND and
CC_EUSED
so defined them here. s/CC_ENOMEM/ENOMEM
So have it return > 0 for the expand case?
I think, its better to have a consistent interface: -ve is error always,
+ve, 0 is success.
chunk_head is given to page_cache_get() before we know it's 'struct
page' or
'struct chunk_head' so need to keep name and its position same as for
struct
page.
Ugh, I missed that detail. That sounds very dangerous and I don't think
it will be allowed. You should find a better way.
Why do you think its 'dangerous'? In very early patches I used a 'struct
page' in place of 'struct chunk_head'. This would have been 'safe' but
that isn't good as sizeof(struct page) is just too big -- metadata size
overhead will explode.
Regards,
Nitin
_______________________________________________
Devel mailing list
[email protected]
http://mailman.laptop.org/mailman/listinfo/devel
