I asked this same question on stack overflow (
here), but haven't gotten any responses. Here is my question:
I am looking at the definition of
in the file
linux/mm_types.h. My question is in regards to the comment at the top of the definition:
Code:
struct page {
unsigned long flags; /* Atomic flags, some possibly
* updated asynchronously */
/*
* Five words (20/40 bytes) are available in this union.
* WARNING: bit 0 of the first word is used for PageTail(). That
* means the other users of this union MUST NOT use the bit to
* avoid collision and false-positive PageTail().
*/
If I want to use these 20 bytes to store metadata about a page, how would I do so? Is there anything that I would need to check before overwriting those addresses, so that I don't corrupt any valid data that was supposed to be there?
