From 0b14c179a483e71ea41df2aa4a661760063115bd Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 21 Nov 2005 21:32:15 -0800 Subject: [PATCH] unpaged: VM_UNPAGED Although we tend to associate VM_RESERVED with remap_pfn_range, quite a few drivers set VM_RESERVED on areas which are then populated by nopage. The PageReserved removal in 2.6.15-rc1 changed VM_RESERVED not to free pages in zap_pte_range, without changing those drivers not to set it: so their pages just leak away. Let's not change miscellaneous drivers now: introduce VM_UNPAGED at the core, to flag the special areas where the ptes may have no struct page, or if they have then it's not to be touched. Replace most instances of VM_RESERVED in core mm by VM_UNPAGED. Force it on in remap_pfn_range, and the sparc and sparc64 io_remap_pfn_range. Revert addition of VM_RESERVED to powerpc vdso, it's not needed there. Is it needed anywhere? It still governs the mm->reserved_vm statistic, and special vmas not to be merged, and areas not to be core dumped; but could probably be eliminated later (the drivers are probably specifying it because in 2.4 it kept swapout off the vma, but in 2.6 we work from the LRU, which these pages don't get on). Use the VM_SHM slot for VM_UNPAGED, and define VM_SHM to 0: it serves no purpose whatsoever, and should be removed from drivers when we clean up. Signed-off-by: Hugh Dickins Acked-by: William Irwin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mm.h b/include/linux/mm.h index 9701210c6680..f0cdfd18db55 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -144,7 +144,8 @@ extern unsigned int kobjsize(const void *objp); #define VM_GROWSDOWN 0x00000100 /* general info on the segment */ #define VM_GROWSUP 0x00000200 -#define VM_SHM 0x00000400 /* shared memory area, don't swap out */ +#define VM_SHM 0x00000000 /* Means nothing: delete it later */ +#define VM_UNPAGED 0x00000400 /* Pages managed without map count */ #define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */ #define VM_EXECUTABLE 0x00001000 @@ -157,7 +158,7 @@ extern unsigned int kobjsize(const void *objp); #define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */ #define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */ -#define VM_RESERVED 0x00080000 /* Pages managed in a special way */ +#define VM_RESERVED 0x00080000 /* Count as reserved_vm like IO */ #define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */ #define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */ #define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */ -- cgit v1.2.2