Head page and T donates its tail page(s). 15 - COMPOUND_HEAD A compound page with order N consists of 2^N physically contiguous pages.Ī compound page with order 2 takes the form of “HTTT”, where H donates its The buddy system organizes free memory in blocks of various orders.Īn order N block has 2^N physically contiguous pages, with the BUDDY flag 10 - BUDDY a free memory block managed by the buddy system allocator When compound page is used, SLUB/SLQB will only set this flag on the head by undergoing read/write IO 7 - SLAB page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator Short descriptions to the page flags ¶ 0 - LOCKED page is being locked for exclusive access, e.g. The page-types tool in the tools/vm directory can be used to query the Times each page is mapped, indexed by PFN. This file contains a 64-bit count of the number of Precisely which pages are mapped (or in swap) and comparing mappedĮfficient users of this interface will use /proc/pid/maps toĭetermine which areas of memory are actually mapped and llseek to If the page is not present but in swap, then the PFN contains anĮncoding of the swap file number and the page’s offset into the Reason: information about PFNs helps in exploiting Rowhammer vulnerability. Starting fromĤ.2 the PFN field is zeroed if the user does not have CAP_SYS_ADMIN. In 4.0 and 4.1 opens by unprivileged fail with -EPERM. Since Linux 4.0 only users with the CAP_SYS_ADMIN capability can get PFNs. Bit 61 page is file-page or shared-anon (since 3.5).Bit 56 page exclusively mapped (since 4.2).Bits 0-54 page frame number (PFN) if presentĭocumentation/admin-guide/mm/soft-dirty.rst).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |