>>>>> "Martin" == Martin Maletinsky <maletinsky@scs.ch> writes:
Martin> In the char/mem.c driver code, the VM_RESERVED flag is set in
Martin> the vma structure. The swap_out_pmd() function uses the
Martin> PageReserved() macro, to check if a page structure's
Martin> PG_reserved flag is set. Did I overlook something, or is there
Martin> any relation between a vma structure's VM_RESERVED flag and
Martin> the page structures's PG_reserved flag.
Martin> Also I noticed, that pte_remap_page_range() which is called
Martin> during execution of remap_page_range() does explicitely check
Martin> the PG_reserved flag of the page to be mapped (as shown in the
Martin> subsequent lines of code).
Martin> if ((!VALID_PAGE(page)) || PageReserved(page))
Martin> set_pte(pte, mk_pte_phys(phys_addr, prot));
Martin> So why does the memory mapping with the remap_page_range()
Martin> call of the char/mem.c driver succeed although it doesn't set
Martin> the reserved bit of the corresponding page structure (but only
Martin> of the corresponding vm area)?
Uh, oh, indeed VM_RESERVED is checked earlier:
vmscan.c:
/* mm->page_table_lock is held. mmap_sem is not held */
static inline int swap_out_vma(struct mm_struct * mm, struct vm_area_struct * vma, unsigned long address, int count, zone_t * classzone)
{
pgd_t *pgdir;
unsigned long end;
/* Don't swap out areas which are reserved */
if (vma->vm_flags & VM_RESERVED)
return count;
[...]
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