- 25 7月, 2008 5 次提交
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由 Andi Kleen 提交于
The goal of this patchset is to support multiple hugetlb page sizes. This is achieved by introducing a new struct hstate structure, which encapsulates the important hugetlb state and constants (eg. huge page size, number of huge pages currently allocated, etc). The hstate structure is then passed around the code which requires these fields, they will do the right thing regardless of the exact hstate they are operating on. This patch adds the hstate structure, with a single global instance of it (default_hstate), and does the basic work of converting hugetlb to use the hstate. Future patches will add more hstate structures to allow for different hugetlbfs mounts to have different page sizes. [akpm@linux-foundation.org: coding-style fixes] Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
hugetlb: guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed After patch 2 in this series, a process that successfully calls mmap() for a MAP_PRIVATE mapping will be guaranteed to successfully fault until a process calls fork(). At that point, the next write fault from the parent could fail due to COW if the child still has a reference. We only reserve pages for the parent but a copy must be made to avoid leaking data from the parent to the child after fork(). Reserves could be taken for both parent and child at fork time to guarantee faults but if the mapping is large it is highly likely we will not have sufficient pages for the reservation, and it is common to fork only to exec() immediatly after. A failure here would be very undesirable. Note that the current behaviour of mainline with MAP_PRIVATE pages is pretty bad. The following situation is allowed to occur today. 1. Process calls mmap(MAP_PRIVATE) 2. Process calls mlock() to fault all pages and makes sure it succeeds 3. Process forks() 4. Process writes to MAP_PRIVATE mapping while child still exists 5. If the COW fails at this point, the process gets SIGKILLed even though it had taken care to ensure the pages existed This patch improves the situation by guaranteeing the reliability of the process that successfully calls mmap(). When the parent performs COW, it will try to satisfy the allocation without using reserves. If that fails the parent will steal the page leaving any children without a page. Faults from the child after that point will result in failure. If the child COW happens first, an attempt will be made to allocate the page without reserves and the child will get SIGKILLed on failure. To summarise the new behaviour: 1. If the original mapper performs COW on a private mapping with multiple references, it will attempt to allocate a hugepage from the pool or the buddy allocator without using the existing reserves. On fail, VMAs mapping the same area are traversed and the page being COW'd is unmapped where found. It will then steal the original page as the last mapper in the normal way. 2. The VMAs the pages were unmapped from are flagged to note that pages with data no longer exist. Future no-page faults on those VMAs will terminate the process as otherwise it would appear that data was corrupted. A warning is printed to the console that this situation occured. 2. If the child performs COW first, it will attempt to satisfy the COW from the pool if there are enough pages or via the buddy allocator if overcommit is allowed and the buddy allocator can satisfy the request. If it fails, the child will be killed. If the pool is large enough, existing applications will not notice that the reserves were a factor. Existing applications depending on the no-reserves been set are unlikely to exist as for much of the history of hugetlbfs, pages were prefaulted at mmap(), allocating the pages at that point or failing the mmap(). [npiggin@suse.de: fix CONFIG_HUGETLB=n build] Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Beulich 提交于
The double indirection here is not needed anywhere and hence (at least) confusing. Signed-off-by: NJan Beulich <jbeulich@novell.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Acked-by: NJeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Rik van Riel 提交于
In order to be able to debug things like the X server and programs using the PPC Cell SPUs, the debugger needs to be able to access device memory through ptrace and /proc/pid/mem. This patch: Add the generic_access_phys access function and put the hooks in place to allow access_process_vm to access device or PPC Cell SPU memory. [riel@redhat.com: Add documentation for the vm_ops->access function] Signed-off-by: NRik van Riel <riel@redhat.com> Signed-off-by: NBenjamin Herrensmidt <benh@kernel.crashing.org> Cc: Dave Airlie <airlied@linux.ie> Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
There are no users of nopfn in the tree. Remove it. [hugh@veritas.com: fix build error] Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 7月, 2008 2 次提交
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由 Oleg Nesterov 提交于
get_user_pages() must not return the error when i != 0. When pages != NULL we have i get_page()'ed pages. Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Acked-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Peter Zijlstra 提交于
Dirty page accounting accurately measures the amound of dirty pages in writable shared mappings by mapping the pages RO (as indicated by vma_wants_writenotify). We then trap on first write and call set_page_dirty() on the page, after which we map the page RW and continue execution. When we launder dirty pages, we call clear_page_dirty_for_io() which clears both the dirty flag, and maps the page RO again before we start writeout so that the story can repeat itself. vma_wants_writenotify() excludes VM_PFNMAP on the basis that we cannot do the regular dirty page stuff on raw PFNs and the memory isn't going anywhere anyway. The recently introduced VM_MIXEDMAP mixes both !pfn_valid() and pfn_valid() pages in a single mapping. We can't do dirty page accounting on !pfn_valid() pages as stated above, and mapping them RO causes them to be COW'ed on write, which breaks VM_SHARED semantics. Excluding VM_MIXEDMAP in vma_wants_writenotify() would mean we don't do the regular dirty page accounting for the pfn_valid() pages, which would bring back all the head-aches from inaccurate dirty page accounting. So instead, we let the !pfn_valid() pages get mapped RO, but fix them up unconditionally in the fault path. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by: NHugh Dickins <hugh@veritas.com> Cc: "Jared Hulbert" <jaredeh@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 6月, 2008 2 次提交
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由 Nick Piggin 提交于
There is a race in the COW logic. It contains a shortcut to avoid the COW and reuse the page if we have the sole reference on the page, however it is possible to have two racing do_wp_page()ers with one causing the other to mistakenly believe it is safe to take the shortcut when it is not. This could lead to data corruption. Process 1 and process2 each have a wp pte of the same anon page (ie. one forked the other). The page's mapcount is 2. Then they both attempt to write to it around the same time... proc1 proc2 thr1 proc2 thr2 CPU0 CPU1 CPU3 do_wp_page() do_wp_page() trylock_page() can_share_swap_page() load page mapcount (==2) reuse = 0 pte unlock copy page to new_page pte lock page_remove_rmap(page); trylock_page() can_share_swap_page() load page mapcount (==1) reuse = 1 ptep_set_access_flags (allow W) write private key into page read from page ptep_clear_flush() set_pte_at(pte of new_page) Fix this by moving the page_remove_rmap of the old page after the pte clear and flush. Potentially the entire branch could be moved down here, but in order to stay consistent, I won't (should probably move all the *_mm_counter stuff with one patch). Signed-off-by: NNick Piggin <npiggin@suse.de> Acked-by: NHugh Dickins <hugh@veritas.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
Commit 89f5b7da ("Reinstate ZERO_PAGE optimization in 'get_user_pages()' and fix XIP") broke vmware, as reported by Jeff Chua: "This broke vmware 6.0.4. Jun 22 14:53:03.845: vmx| NOT_IMPLEMENTED /build/mts/release/bora-93057/bora/vmx/main/vmmonPosix.c:774" and the reason seems to be that there's an old bug in how we handle do FOLL_ANON on VM_SHARED areas in get_user_pages(), but since it only triggered if the whole page table was missing, nobody had apparently hit it before. The recent changes to 'follow_page()' made the FOLL_ANON logic trigger not just for whole missing page tables, but for individual pages as well, and exposed this problem. This fixes it by making the test for when FOLL_ANON is used more careful, and also makes the code easier to read and understand by moving the logic to a separate inline function. Reported-and-tested-by: NJeff Chua <jeff.chua.linux@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 21 6月, 2008 1 次提交
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由 Linus Torvalds 提交于
KAMEZAWA Hiroyuki and Oleg Nesterov point out that since the commit 557ed1fa ("remove ZERO_PAGE") removed the ZERO_PAGE from the VM mappings, any users of get_user_pages() will generally now populate the VM with real empty pages needlessly. We used to get the ZERO_PAGE when we did the "handle_mm_fault()", but since fault handling no longer uses ZERO_PAGE for new anonymous pages, we now need to handle that special case in follow_page() instead. In particular, the removal of ZERO_PAGE effectively removed the core file writing optimization where we would skip writing pages that had not been populated at all, and increased memory pressure a lot by allocating all those useless newly zeroed pages. This reinstates the optimization by making the unmapped PTE case the same as for a non-existent page table, which already did this correctly. While at it, this also fixes the XIP case for follow_page(), where the caller could not differentiate between the case of a page that simply could not be used (because it had no "struct page" associated with it) and a page that just wasn't mapped. We do that by simply returning an error pointer for pages that could not be turned into a "struct page *". The error is arbitrarily picked to be EFAULT, since that was what get_user_pages() already used for the equivalent IO-mapped page case. [ Also removed an impossible test for pte_offset_map_lock() failing: that's not how that function works ] Acked-by: NOleg Nesterov <oleg@tv-sign.ru> Acked-by: NNick Piggin <npiggin@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 5月, 2008 1 次提交
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由 Nick Piggin 提交于
Take out an assertion to allow ->fault handlers to service PFNMAP regions. This is required to reimplement .nopfn handlers with .fault handlers and subsequently remove nopfn. Signed-off-by: NNick Piggin <npiggin@suse.de> Acked-by: NJes Sorensen <jes@sgi.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 5月, 2008 1 次提交
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由 Nick Piggin 提交于
There is a possible data race in the page table walking code. After the split ptlock patches, it actually seems to have been introduced to the core code, but even before that I think it would have impacted some architectures (powerpc and sparc64, at least, walk the page tables without taking locks eg. see find_linux_pte()). The race is as follows: The pte page is allocated, zeroed, and its struct page gets its spinlock initialized. The mm-wide ptl is then taken, and then the pte page is inserted into the pagetables. At this point, the spinlock is not guaranteed to have ordered the previous stores to initialize the pte page with the subsequent store to put it in the page tables. So another Linux page table walker might be walking down (without any locks, because we have split-leaf-ptls), and find that new pte we've inserted. It might try to take the spinlock before the store from the other CPU initializes it. And subsequently it might read a pte_t out before stores from the other CPU have cleared the memory. There are also similar races in higher levels of the page tables. They obviously don't involve the spinlock, but could see uninitialized memory. Arch code and hardware pagetable walkers that walk the pagetables without locks could see similar uninitialized memory problems, regardless of whether split ptes are enabled or not. I prefer to put the barriers in core code, because that's where the higher level logic happens, but the page table accessors are per-arch, and open-coding them everywhere I don't think is an option. I'll put the read-side barriers in alpha arch code for now (other architectures perform data-dependent loads in order). Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 5月, 2008 1 次提交
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由 Hugh Dickins 提交于
Fix warning from pmd_bad() at bootup on a HIGHMEM64G HIGHPTE x86_32. That came from 9fc34113 x86: debug pmd_bad(); but we understand now that the typecasting was wrong for PAE in the previous version: pagetable pages above 4GB looked bad and stopped Arjan from booting. And revert that cded932b x86: fix pmd_bad and pud_bad to support huge pages. It was the wrong way round: we shouldn't weaken every pmd_bad and pud_bad check to let huge pages slip through - in part they check that we _don't_ have a huge page where it's not expected. Put the x86 pmd_bad() and pud_bad() definitions back to what they have long been: they can be improved (x86_32 should use PTE_MASK, to stop PAE thinking junk in the upper word is good; and x86_64 should follow x86_32's stricter comparison, to stop thinking any subset of required bits is good); but that should be a later patch. Fix Hans' good observation that follow_page() will never find pmd_huge() because that would have already failed the pmd_bad test: test pmd_huge in between the pmd_none and pmd_bad tests. Tighten x86's pmd_huge() check? No, once it's a hugepage entry, it can get quite far from a good pmd: for example, PROT_NONE leaves it with only ACCESSED of the KERN_PGTABLE bits. However... though follow_page() contains this and another test for huge pages, so it's nice to keep it working on them, where does it actually get called on a huge page? get_user_pages() checks is_vm_hugetlb_page(vma) to to call alternative hugetlb processing, as does unmap_vmas() and others. Signed-off-by: NHugh Dickins <hugh@veritas.com> Earlier-version-tested-by: NIngo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jeff Chua <jeff.chua.linux@gmail.com> Cc: Hans Rosenfeld <hans.rosenfeld@amd.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 4月, 2008 4 次提交
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由 Nick Piggin 提交于
vm_insert_mixed will insert either a raw pfn or a refcounted struct page into the page tables, depending on whether vm_normal_page() will return the page or not. With the introduction of the new pte bit, this is now a too tricky for drivers to be doing themselves. filemap_xip uses this in a subsequent patch. Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory model (which is more dynamic than most). Instead, they had proposed to implement it with an additional path through vm_normal_page(), using a bit in the pte to determine whether or not the page should be refcounted: vm_normal_page() { ... if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { if (vma->vm_flags & VM_MIXEDMAP) { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; #else if (!pfn_valid(pfn)) return NULL; #endif goto out; } ... } This is fine, however if we are allowed to use a bit in the pte to determine refcountedness, we can use that to _completely_ replace all the vma based schemes. So instead of adding more cases to the already complex vma-based scheme, we can have a clearly seperate and simple pte-based scheme (and get slightly better code generation in the process): vm_normal_page() { #ifdef s390 if (!mixedmap_refcount_pte(pte)) return NULL; return pte_page(pte); #else ... #endif } And finally, we may rather make this concept usable by any architecture rather than making it s390 only, so implement a new type of pte state for this. Unfortunately the old vma based code must stay, because some architectures may not be able to spare pte bits. This makes vm_normal_page a little bit more ugly than we would like, but the 2 cases are clearly seperate. So introduce a pte_special pte state, and use it in mm/memory.c. It is currently a noop for all architectures, so this doesn't actually result in any compiled code changes to mm/memory.o. BTW: I haven't put vm_normal_page() into arch code as-per an earlier suggestion. The reason is that, regardless of where vm_normal_page is actually implemented, the *abstraction* is still exactly the same. Also, while it depends on whether the architecture has pte_special or not, that is the only two possible cases, and it really isn't an arch specific function -- the role of the arch code should be to provide primitive functions and accessors with which to build the core code; pte_special does that. We do not want architectures to know or care about vm_normal_page itself, and we definitely don't want them being able to invent something new there out of sight of mm/ code. If we made vm_normal_page an arch function, then we have to make vm_insert_mixed (next patch) an arch function too. So I don't think moving it to arch code fundamentally improves any abstractions, while it does practically make the code more difficult to follow, for both mm and arch developers, and easier to misuse. [akpm@linux-foundation.org: build fix] Signed-off-by: NNick Piggin <npiggin@suse.de> Acked-by: NCarsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jared Hulbert 提交于
This series introduces some important infrastructure work. The overall result is that: 1. We now support XIP backed filesystems using memory that have no struct page allocated to them. And patches 6 and 7 actually implement this for s390. This is pretty important in a number of cases. As far as I understand, in the case of virtualisation (eg. s390), each guest may mount a readonly copy of the same filesystem (eg. the distro). Currently, guests need to allocate struct pages for this image. So if you have 100 guests, you already need to allocate more memory for the struct pages than the size of the image. I think. (Carsten?) For other (eg. embedded) systems, you may have a very large non- volatile filesystem. If you have to have struct pages for this, then your RAM consumption will go up proportionally to fs size. Even though it is just a small proportion, the RAM can be much more costly eg in terms of power, so every KB less that Linux uses makes it more attractive to a lot of these guys. 2. VM_MIXEDMAP allows us to support mappings where you actually do want to refcount _some_ pages in the mapping, but not others, and support COW on arbitrary (non-linear) mappings. Jared needs this for his NVRAM filesystem in progress. Future iterations of this filesystem will most likely want to migrate pages between pagecache and XIP backing, which is where the requirement for mixed (some refcounted, some not) comes from. 3. pte_special also has a peripheral usage that I need for my lockless get_user_pages patch. That was shown to speed up "oltp" on db2 by 10% on a 2 socket system, which is kind of significant because they scrounge for months to try to find 0.1% improvement on these workloads. I'm hoping we might finally be faster than AIX on pSeries with this :). My reference to lockless get_user_pages is not meant to justify this patchset (which doesn't include lockless gup), but just to show that pte_special is not some s390 specific thing that should be hidden in arch code or xip code: I definitely want to use it on at least x86 and powerpc as well. This patch: Introduce a new type of mapping, VM_MIXEDMAP. This is unlike VM_PFNMAP in that it can support COW mappings of arbitrary ranges including ranges without struct page *and* ranges with a struct page that we actually want to refcount (PFNMAP can only support COW in those cases where the un-COW-ed translations are mapped linearly in the virtual address, and can only support non refcounted ranges). VM_MIXEDMAP achieves this by refcounting all pfn_valid pages, and not refcounting !pfn_valid pages (which is not an option for VM_PFNMAP, because it needs to avoid refcounting pfn_valid pages eg. for /dev/mem mappings). Signed-off-by: NJared Hulbert <jaredeh@gmail.com> Signed-off-by: NNick Piggin <npiggin@suse.de> Acked-by: NCarsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nick Piggin 提交于
Nothing in the tree uses nopage any more. Remove support for it in the core mm code and documentation (and a few stray references to it in comments). Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 3月, 2008 2 次提交
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由 Hugh Dickins 提交于
Don't uncharge when do_swap_page's call to do_wp_page fails: the page which was charged for is there in the pagetable, and will be correctly uncharged when that area is unmapped - it was only its COWing which failed. And while we're here, remove earlier XXX comment: yes, OR in do_wp_page's return value (maybe VM_FAULT_WRITE) with do_swap_page's there; but if it fails, mask out success bits, which might confuse some arches e.g. sparc. Signed-off-by: NHugh Dickins <hugh@veritas.com> Cc: David Rientjes <rientjes@google.com> Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
There's nothing wrong with mem_cgroup_charge failure in do_wp_page and do_anonymous page using __free_page, but it does look odd when nearby code uses page_cache_release: use that instead (while turning a blind eye to ancient inconsistencies of page_cache_release versus put_page). Signed-off-by: NHugh Dickins <hugh@veritas.com> Cc: David Rientjes <rientjes@google.com> Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 2月, 2008 2 次提交
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由 Jan Blunck 提交于
d_path() is used on a <dentry,vfsmount> pair. Lets use a struct path to reflect this. [akpm@linux-foundation.org: fix build in mm/memory.c] Signed-off-by: NJan Blunck <jblunck@suse.de> Acked-by: NBryan Wu <bryan.wu@analog.com> Acked-by: NChristoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Neil Brown <neilb@suse.de> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ingo Molnar 提交于
Jiri Kosina reported the following deadlock scenario with show_unhandled_signals enabled: [ 68.379022] gnome-settings-[2941] trap int3 ip:3d2c840f34 sp:7fff36f5d100 error:0<3>BUG: sleeping function called from invalid context at kernel/rwsem.c:21 [ 68.379039] in_atomic():1, irqs_disabled():0 [ 68.379044] no locks held by gnome-settings-/2941. [ 68.379050] Pid: 2941, comm: gnome-settings- Not tainted 2.6.25-rc1 #30 [ 68.379054] [ 68.379056] Call Trace: [ 68.379061] <#DB> [<ffffffff81064883>] ? __debug_show_held_locks+0x13/0x30 [ 68.379109] [<ffffffff81036765>] __might_sleep+0xe5/0x110 [ 68.379123] [<ffffffff812f2240>] down_read+0x20/0x70 [ 68.379137] [<ffffffff8109cdca>] print_vma_addr+0x3a/0x110 [ 68.379152] [<ffffffff8100f435>] do_trap+0xf5/0x170 [ 68.379168] [<ffffffff8100f52b>] do_int3+0x7b/0xe0 [ 68.379180] [<ffffffff812f4a6f>] int3+0x9f/0xd0 [ 68.379203] <<EOE>> [ 68.379229] in libglib-2.0.so.0.1505.0[3d2c800000+dc000] and tracked it down to: commit 03252919 Author: Andi Kleen <ak@suse.de> Date: Wed Jan 30 13:33:18 2008 +0100 x86: print which shared library/executable faulted in segfault etc. messages the problem is that we call down_read() from an atomic context. Solve this by returning from print_vma_addr() if the preempt count is elevated. Update preempt_conditional_sti / preempt_conditional_cli to unconditionally lift the preempt count even on !CONFIG_PREEMPT. Reported-by: NJiri Kosina <jkosina@suse.cz> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 12 2月, 2008 1 次提交
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由 Jonathan Corbet 提交于
So I spent a while pounding my head against my monitor trying to figure out the vmsplice() vulnerability - how could a failure to check for *read* access turn into a root exploit? It turns out that it's a buffer overflow problem which is made easy by the way get_user_pages() is coded. In particular, "len" is a signed int, and it is only checked at the *end* of a do {} while() loop. So, if it is passed in as zero, the loop will execute once and decrement len to -1. At that point, the loop will proceed until the next invalid address is found; in the process, it will likely overflow the pages array passed in to get_user_pages(). I think that, if get_user_pages() has been asked to grab zero pages, that's what it should do. Thus this patch; it is, among other things, enough to block the (already fixed) root exploit and any others which might be lurking in similar code. I also think that the number of pages should be unsigned, but changing the prototype of this function probably requires some more careful review. Signed-off-by: NJonathan Corbet <corbet@lwn.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 2月, 2008 1 次提交
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由 Martin Schwidefsky 提交于
Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 2月, 2008 2 次提交
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由 Balbir Singh 提交于
Nick Piggin pointed out that swap cache and page cache addition routines could be called from non GFP_KERNEL contexts. This patch makes the charging routine aware of the gfp context. Charging might fail if the cgroup is over it's limit, in which case a suitable error is returned. This patch was tested on a Powerpc box. I am still looking at being able to test the path, through which allocations happen in non GFP_KERNEL contexts. [kamezawa.hiroyu@jp.fujitsu.com: problem with ZONE_MOVABLE] Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Balbir Singh 提交于
Add the accounting hooks. The accounting is carried out for RSS and Page Cache (unmapped) pages. There is now a common limit and accounting for both. The RSS accounting is accounted at page_add_*_rmap() and page_remove_rmap() time. Page cache is accounted at add_to_page_cache(), __delete_from_page_cache(). Swap cache is also accounted for. Each page's page_cgroup is protected with the last bit of the page_cgroup pointer, this makes handling of race conditions involving simultaneous mappings of a page easier. A reference count is kept in the page_cgroup to deal with cases where a page might be unmapped from the RSS of all tasks, but still lives in the page cache. Credits go to Vaidyanathan Srinivasan for helping with reference counting work of the page cgroup. Almost all of the page cache accounting code has help from Vaidyanathan Srinivasan. [hugh@veritas.com: fix swapoff breakage] [akpm@linux-foundation.org: fix locking] Signed-off-by: NVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: <Valdis.Kletnieks@vt.edu> Signed-off-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 2月, 2008 1 次提交
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由 Ingo Molnar 提交于
based on similar patch from: Pavel Machek <pavel@ucw.cz> Introduce CONFIG_COMPAT_BRK. If disabled then the kernel is free (but not obliged to) randomize the brk area. Heap randomization breaks ancient binaries, so we keep COMPAT_BRK enabled by default. Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 06 2月, 2008 8 次提交
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由 Nick Piggin 提交于
After running SetPageUptodate, preceeding stores to the page contents to actually bring it uptodate may not be ordered with the store to set the page uptodate. Therefore, another CPU which checks PageUptodate is true, then reads the page contents can get stale data. Fix this by having an smp_wmb before SetPageUptodate, and smp_rmb after PageUptodate. Many places that test PageUptodate, do so with the page locked, and this would be enough to ensure memory ordering in those places if SetPageUptodate were only called while the page is locked. Unfortunately that is not always the case for some filesystems, but it could be an idea for the future. Also bring the handling of anonymous page uptodateness in line with that of file backed page management, by marking anon pages as uptodate when they _are_ uptodate, rather than when our implementation requires that they be marked as such. Doing allows us to get rid of the smp_wmb's in the page copying functions, which were especially added for anonymous pages for an analogous memory ordering problem. Both file and anonymous pages are handled with the same barriers. FAQ: Q. Why not do this in flush_dcache_page? A. Firstly, flush_dcache_page handles only one side (the smb side) of the ordering protocol; we'd still need smp_rmb somewhere. Secondly, hiding away memory barriers in a completely unrelated function is nasty; at least in the PageUptodate macros, they are located together with (half) the operations involved in the ordering. Thirdly, the smp_wmb is only required when first bringing the page uptodate, wheras flush_dcache_page should be called each time it is written to through the kernel mapping. It is logically the wrong place to put it. Q. Why does this increase my text size / reduce my performance / etc. A. Because it is adding the necessary instructions to eliminate the data-race. Q. Can it be improved? A. Yes, eg. if you were to create a rule that all SetPageUptodate operations run under the page lock, we could avoid the smp_rmb places where PageUptodate is queried under the page lock. Requires audit of all filesystems and at least some would need reworking. That's great you're interested, I'm eagerly awaiting your patches. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Harvey Harrison 提交于
fastcall is always defined to be empty, remove it [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Benjamin Herrenschmidt 提交于
(with Martin Schwidefsky <schwidefsky@de.ibm.com>) The pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as first argument. The free functions do not get the mm_struct argument. This is 1) asymmetrical and 2) to do mm related page table allocations the mm argument is needed on the free function as well. [kamalesh@linux.vnet.ibm.com: i386 fix] [akpm@linux-foundation.org: coding-syle fixes] Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Hellwig 提交于
vmtruncate is a twisted maze of gotos, this patch cleans it up to have a proper if else for the two major cases of extending and truncating truncate and thus makes it a lot more readable while keeping exactly the same functinality. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
Building in a filesystem on a loop device on a tmpfs file can hang when swapping, the loop thread caught in that infamous throttle_vm_writeout. In theory this is a long standing problem, which I've either never seen in practice, or long ago suppressed the recollection, after discounting my load and my tmpfs size as unrealistically high. But now, with the new aops, it has become easy to hang on one machine. Loop used to grab_cache_page before the old prepare_write to tmpfs, which seems to have been enough to free up some memory for any swapin needed; but the new write_begin lets tmpfs find or allocate the page (much nicer, since grab_cache_page missed tmpfs pages in swapcache). When allocating a fresh page, tmpfs respects loop's mapping_gfp_mask, which has __GFP_IO|__GFP_FS stripped off, and throttle_vm_writeout is designed to break out when __GFP_IO or GFP_FS is unset; but when tmfps swaps in, read_swap_cache_async allocates with GFP_HIGHUSER_MOVABLE regardless of the mapping_gfp_mask - hence the hang. So, pass gfp_mask down the line from shmem_getpage to shmem_swapin to swapin_readahead to read_swap_cache_async to add_to_swap_cache. Signed-off-by: NHugh Dickins <hugh@veritas.com> Acked-by: NRik van Riel <riel@redhat.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
swapin_readahead has never sat well in mm/memory.c: move it to mm/swap_state.c beside its kindred read_swap_cache_async. Why were its args in a different order? rearrange them. And since it was always followed by a read_swap_cache_async of the target page, fold that in and return struct page*. Then CONFIG_SWAP=n no longer needs valid_swaphandles and read_swap_cache_async stubs. Signed-off-by: NHugh Dickins <hugh@veritas.com> Acked-by: NRik van Riel <riel@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
For three years swapin_readahead has been cluttered with fanciful CONFIG_NUMA code, advancing addr, and stepping on to the next vma at the boundary, to line up the mempolicy for each page allocation. It _might_ be a good idea to allocate swap more according to vma layout; but the fact is, that's not how we do it at all, 2.6 even less than 2.4: swap is allocated as needed for pages as they sink to the bottom of the inactive LRUs. Sometimes that may match vma layout, but not so often that it's worth going to these misleading vma->vm_next lengths: rip all that out. Originally I intended to retain the incrementation of addr, but correct its initial value: valid_swaphandles generally supplies an offset below the target addr (this is readaround rather than readahead), but addr has not been adjusted accordingly, so in the interleave case it has usually been allocating the target page from the "wrong" node (though that may not matter very much). But look at the equivalent shmem_swapin code: either by oversight or by design, though it has all the apparatus for choosing a new mempolicy per page, it uses the same idx throughout, choosing the same mempolicy and interleave node for each page of the cluster. Which is actually a much better strategy: each node has its own LRUs and its own kswapd, so if you're betting on any particular relationship between swap and node, the best bet is that nearby swap entries belong to pages from the same node - even when the mempolicy of the target page is to interleave. And examining a map of nodes corresponding to swap entries on a numa=fake system bears this out. (We could later tweak swap allocation to make it even more likely, but this patch is merely about removing cruft.) So, neither adjust nor increment addr in swapin_readahead, and then shmem_swapin can use it too; the pseudo-vma to pass policy need only be set up once per cluster, and so few fields of pvma are used, let's skip the memset - from shmem_alloc_page also. Signed-off-by: NHugh Dickins <hugh@veritas.com> Acked-by: NRik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
We already have page table manipulation for vmalloc in vmalloc.c. Move the vmalloc_to_page() function there as well. Move the definitions for vmalloc related functions in mm.h to a newly created section. A better place would be vmalloc.h but mm.h is basic and may depend on these functions. An alternative would be to include vmalloc.h in mm.h (like done for vmstat.h). Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 1月, 2008 2 次提交
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由 Andi Kleen 提交于
They now look like: hal-resmgr[13791]: segfault at 3c rip 2b9c8caec182 rsp 7fff1e825d30 error 4 in libacl.so.1.1.0[2b9c8caea000+6000] This makes it easier to pinpoint bugs to specific libraries. And printing the offset into a mapping also always allows to find the correct fault point in a library even with randomized mappings. Previously there was no way to actually find the correct code address inside the randomized mapping. Relies on earlier patch to shorten the printk formats. They are often now longer than 80 characters, but I think that's worth it. [includes fix from Eric Dumazet to check d_path error value] Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Nick Piggin 提交于
The break_lock data structure and code for spinlocks is quite nasty. Not only does it double the size of a spinlock but it changes locking to a potentially less optimal trylock. Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a __raw_spin_is_contended that uses the lock data itself to determine whether there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is not set. Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to decouple it from the spinlock implementation, and make it typesafe (rwlocks do not have any need_lockbreak sites -- why do they even get bloated up with that break_lock then?). Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 24 1月, 2008 1 次提交
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由 Anton Salikhmetov 提交于
Update ctime and mtime for memory-mapped files at a write access on a present, read-only PTE, as well as at a write on a non-present PTE. Signed-off-by: NAnton Salikhmetov <salikhmetov@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 1月, 2008 1 次提交
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由 Carsten Otte 提交于
This patch puts #ifdef CONFIG_DEBUG_VM around a check in vm_normal_page that verifies that a pfn is valid. This patch increases performance of the page fault microbenchmark in lmbench by 13% and overall dbench performance by 7% on s390x. pfn_valid() is an expensive operation on s390 that needs a high double digit amount of CPU cycles. Nick Piggin suggested that pfn_valid() involves an array lookup on systems with sparsemem, and therefore is an expensive operation there too. The check looks like a clear debug thing to me, it should never trigger on regular kernels. And if a pte is created for an invalid pfn, we'll find out once the memory gets accessed later on anyway. Please consider inclusion of this patch into mm. Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Acked-by: NNick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 11月, 2007 2 次提交
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由 Balbir Singh 提交于
The delay incurred in lock_page() should also be accounted in swap delay accounting Reported-by: NNick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adam Litke 提交于
When calling get_user_pages(), a write flag is passed in by the caller to indicate if write access is required on the faulted-in pages. Currently, follow_hugetlb_page() ignores this flag and always faults pages for read-only access. This can cause data corruption because a device driver that calls get_user_pages() with write set will not expect COW faults to occur on the returned pages. This patch passes the write flag down to follow_hugetlb_page() and makes sure hugetlb_fault() is called with the right write_access parameter. [ezk@cs.sunysb.edu: build fix] Signed-off-by: NAdam Litke <agl@us.ibm.com> Reviewed-by: NKen Chen <kenchen@google.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: NErez Zadok <ezk@cs.sunysb.edu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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