user/sven/linux.git/include/linux/swapops.h, branch v3.0.45

HWPOISON: Add support for poison swap entries v2

2009-09-16T09:50:05Z

Memory migration uses special swap entry types to trigger special actions on page faults. Extend this mechanism to also support poisoned swap entries, to trigger poison handling on page faults. This allows follow-on patches to prevent processes from faulting in poisoned pages again. v2: Fix overflow in MAX_SWAPFILES (Fengguang Wu) v3: Better overflow fix (Hidehiro Kawai) Signed-off-by: Andi Kleen

Fix compile error on nommu for is_swap_pte

2008-02-09T19:08:33Z

CC mm/vmscan.o In file included from /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/vmscan.c:44: /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/swapops.h: In function 'is_swap_pte': /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/swapops.h:48: error: implicit declaration of function 'pte_none' /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/swapops.h:48: error: implicit declaration of function 'pte_present' Does it ever make sense to ask "is this pte a swap entry?" on a machine with no MMU? Presumably this also means it has no ptes too, right? In which case, it's better to comment the whole function out. Then when someone tries to ask the above meaningless question, they get a compile error rather than a meaningless answer. Signed-off-by: Matt Mackall Cc: Mike Frysinger Reported-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

maps4: move is_swap_pte

2008-02-05T17:44:16Z

Move is_swap_pte helper function to swapops.h for use by pagemap code Signed-off-by: Matt Mackall Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] mincore warning fix

2007-02-21T01:10:13Z

allnoconfig: mm/mincore.c: In function 'do_mincore': mm/mincore.c:122: warning: unused variable 'entry' Yet another entry in the why-macros-are-wrong encyclopedia. Cc: Christoph Lameter Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Swapless page migration: add R/W migration entries

2006-06-23T14:42:50Z

Implement read/write migration ptes We take the upper two swapfiles for the two types of migration ptes and define a series of macros in swapops.h. The VM is modified to handle the migration entries. migration entries can only be encountered when the page they are pointing to is locked. This limits the number of places one has to fix. We also check in copy_pte_range and in mprotect_pte_range() for migration ptes. We check for migration ptes in do_swap_cache and call a function that will then wait on the page lock. This allows us to effectively stop all accesses to apge. Migration entries are created by try_to_unmap if called for migration and removed by local functions in migrate.c From: Hugh Dickins Several times while testing swapless page migration (I've no NUMA, just hacking it up to migrate recklessly while running load), I've hit the BUG_ON(!PageLocked(p)) in migration_entry_to_page. This comes from an orphaned migration entry, unrelated to the current correctly locked migration, but hit by remove_anon_migration_ptes as it checks an address in each vma of the anon_vma list. Such an orphan may be left behind if an earlier migration raced with fork: copy_one_pte can duplicate a migration entry from parent to child, after remove_anon_migration_ptes has checked the child vma, but before it has removed it from the parent vma. (If the process were later to fault on this orphaned entry, it would hit the same BUG from migration_entry_wait.) This could be fixed by locking anon_vma in copy_one_pte, but we'd rather not. There's no such problem with file pages, because vma_prio_tree_add adds child vma after parent vma, and the page table locking at each end is enough to serialize. Follow that example with anon_vma: add new vmas to the tail instead of the head. (There's no corresponding problem when inserting migration entries, because a missed pte will leave the page count and mapcount high, which is allowed for. And there's no corresponding problem when migrating via swap, because a leftover swap entry will be correctly faulted. But the swapless method has no refcounting of its entries.) From: Ingo Molnar pte_unmap_unlock() takes the pte pointer as an argument. From: Hugh Dickins Several times while testing swapless page migration, gcc has tried to exec a pointer instead of a string: smells like COW mappings are not being properly write-protected on fork. The protection in copy_one_pte looks very convincing, until at last you realize that the second arg to make_migration_entry is a boolean "write", and SWP_MIGRATION_READ is 30. Anyway, it's better done like in change_pte_range, using is_write_migration_entry and make_migration_entry_read. From: Hugh Dickins Remove unnecessary obfuscation from sys_swapon's range check on swap type, which blew up causing memory corruption once swapless migration made MAX_SWAPFILES no longer 2 ^ MAX_SWAPFILES_SHIFT. Signed-off-by: Hugh Dickins Acked-by: Martin Schwidefsky Signed-off-by: Hugh Dickins Signed-off-by: Christoph Lameter Signed-off-by: Ingo Molnar From: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] comment typo fix

2005-09-05T07:05:45Z

smp_entry_t -> swap_entry_t Signed-off-by: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Remove redundant AND from swp_type()

2004-10-20T01:40:03Z

There is a useless AND in swp_type() function. We just shifted right SWP_TYPE_SHIFT() bits the value from the swp_entry_t, and then we AND it with "(1 << 5) - 1" (which is a mask corresponding to the number of bits used by "type"). Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Fix swp_entry_t encoding

2004-04-01T05:53:47Z

From: Martin Schwidefsky This fixes a problem in sys_swapon that can cause the creation of invalid swap ptes. This has its cause in the arch-independent swap entries vs. the pte coded swap entries. The swp_entry_t uses 27 bits for the offset and 5 bits for the type. In sys_swapon this definition is used to find how many swap devices and how many pages on each device there can be. But the swap entries encoded in a pte can be subject to additional restrictions due to the hardware besides the 27/5 division of the bits in the swp_entry_t type. This is solved by adding pte_to_swp_entry and swp_entry_to_pte calls to the calculations for maximum type and offset. In addition the s390 swap pte division for offset/type is changed from 19/6 bits to 20/5 bits.

[PATCH] Make nonlinear mappings fully pageable

2003-03-22T15:32:42Z

This patch requires arch support. I have patches for ia32, ppc64 and x86_64. Other architectures will break. It is a five-minute fix. See http://mail.nl.linux.org/linux-mm/2003-03/msg00174.html for implementation details. Patch from: Ingo Molnar the attached patch, against BK-curr, is a preparation to make remap_file_pages() usable on swappable vmas as well. When 'swapping out' shared-named mappings the page offset is written into the pte. it takes one bit from the swap-type bits, otherwise it does not change the pte layout - so it should be easy to adapt any other architecture to this change as well. (this patch does not introduce the protection-bits-in-pte approach used in my previous patch.) On 32-bit pte sizes with an effective usable pte range of 29 bits, this limits mmap()-able file size to 4096 * 2^29 == 2 TBs. If the usable range is smaller, then the maximum mmap() size is reduced as well. The worst-case i found (PPC) was 2 hw-reserved bits in the swap-case, which limits us to 1 TB filesize. Is there any other hw that has an even worse ratio of sw-usable pte bits? this mmap() limit can be eliminated by simply not converting the swapped out pte to a file-pte, but clearning it and falling back to the linear mapping upon swapin. This puts the limit into remap_file_pages() alone, but i really hope no-one wants to use remap_file_pages() on a 32-bit platform, on a larger than 1-2 TB file. sys_remap_file_pages() is now enforcing the 'prot' parameter to be zero. This restriction might be lifted in the future - i really hope we can have more flexible remapping once 64-bit platforms are commonplace - eg. things like memory debuggers could just use the permission bits directly, instead of creating many small vmas. i've tested swappable nonlinear ptes and they are swapped out/in correctly. some other changes in -A0 relative to 2.5.63-BK: - slightly smarter TLB flushing in install_page(). This is still only a stupid helper functions - a more efficient 'walk the pagecache tree and pagetable at once and use TLB-gather' implementation is preferred. - cleanup: pass on pgprot_t instead of unsigned long prot. - some sanity checks to make sure file_pte() rules are followed. - do not reduce the vma's default protection to PROT_NONE when using remap_file_pages() on it. With swappable ptes this is now safe.

[PATCH] Fix for recent swap changes on 64 bit archs

2002-06-03T04:58:18Z

This fixes two shift warnings on 64 bit archs.