linux/mm/rmap.c, branch v3.2.38

mm: fix XFS oops due to dirty pages without buffers on s390

2012-10-30T23:27:06Z

commit ef5d437f71afdf4afdbab99213add99f4b1318fd upstream. On s390 any write to a page (even from kernel itself) sets architecture specific page dirty bit. Thus when a page is written to via buffered write, HW dirty bit gets set and when we later map and unmap the page, page_remove_rmap() finds the dirty bit and calls set_page_dirty(). Dirtying of a page which shouldn't be dirty can cause all sorts of problems to filesystems. The bug we observed in practice is that buffers from the page get freed, so when the page gets later marked as dirty and writeback writes it, XFS crashes due to an assertion BUG_ON(!PagePrivate(page)) in page_buffers() called from xfs_count_page_state(). Similar problem can also happen when zero_user_segment() call from xfs_vm_writepage() (or block_write_full_page() for that matter) set the hardware dirty bit during writeback, later buffers get freed, and then page unmapped. Fix the issue by ignoring s390 HW dirty bit for page cache pages of mappings with mapping_cap_account_dirty(). This is safe because for such mappings when a page gets marked as writeable in PTE it is also marked dirty in do_wp_page() or do_page_fault(). When the dirty bit is cleared by clear_page_dirty_for_io(), the page gets writeprotected in page_mkclean(). So pagecache page is writeable if and only if it is dirty. Thanks to Hugh Dickins for pointing out mapping has to have mapping_cap_account_dirty() for things to work and proposing a cleaned up variant of the patch. The patch has survived about two hours of running fsx-linux on tmpfs while heavily swapping and several days of running on out build machines where the original problem was triggered. Signed-off-by: Jan Kara Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Hugh Dickins Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context; in particular there is no local 'anon' in page_remove_rmap()] Signed-off-by: Ben Hutchings

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-07T03:44:47Z

* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits) Revert "tracing: Include module.h in define_trace.h" irq: don't put module.h into irq.h for tracking irqgen modules. bluetooth: macroize two small inlines to avoid module.h ip_vs.h: fix implicit use of module_get/module_put from module.h nf_conntrack.h: fix up fallout from implicit moduleparam.h presence include: replace linux/module.h with "struct module" wherever possible include: convert various register fcns to macros to avoid include chaining crypto.h: remove unused crypto_tfm_alg_modname() inline uwb.h: fix implicit use of asm/page.h for PAGE_SIZE pm_runtime.h: explicitly requires notifier.h linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h miscdevice.h: fix up implicit use of lists and types stop_machine.h: fix implicit use of smp.h for smp_processor_id of: fix implicit use of errno.h in include/linux/of.h of_platform.h: delete needless include acpi: remove module.h include from platform/aclinux.h miscdevice.h: delete unnecessary inclusion of module.h device_cgroup.h: delete needless include net: sch_generic remove redundant use of net: inet_timewait_sock doesnt need ... Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in - drivers/media/dvb/frontends/dibx000_common.c - drivers/media/video/{mt9m111.c,ov6650.c} - drivers/mfd/ab3550-core.c - include/linux/dmaengine.h

ksm: fix the comment of try_to_unmap_one()

2011-11-01T00:30:49Z

try_to_unmap_one() is called by try_to_unmap_ksm(), too. Signed-off-by: Wanlong Gao Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: Map most files to use export.h instead of module.h

2011-10-31T13:20:12Z

The files changed within are only using the EXPORT_SYMBOL macro variants. They are not using core modular infrastructure and hence don't need module.h but only the export.h header. Signed-off-by: Paul Gortmaker

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback

2011-07-26T17:39:54Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback: (27 commits) mm: properly reflect task dirty limits in dirty_exceeded logic writeback: don't busy retry writeback on new/freeing inodes writeback: scale IO chunk size up to half device bandwidth writeback: trace global_dirty_state writeback: introduce max-pause and pass-good dirty limits writeback: introduce smoothed global dirty limit writeback: consolidate variable names in balance_dirty_pages() writeback: show bdi write bandwidth in debugfs writeback: bdi write bandwidth estimation writeback: account per-bdi accumulated written pages writeback: make writeback_control.nr_to_write straight writeback: skip tmpfs early in balance_dirty_pages_ratelimited_nr() writeback: trace event writeback_queue_io writeback: trace event writeback_single_inode writeback: remove .nonblocking and .encountered_congestion writeback: remove writeback_control.more_io writeback: skip balance_dirty_pages() for in-memory fs writeback: add bdi_dirty_limit() kernel-doc writeback: avoid extra sync work at enqueue time writeback: elevate queue_io() into wb_writeback() ... Fix up trivial conflicts in fs/fs-writeback.c and mm/filemap.c

[S390] reference bit testing for unmapped pages

2011-07-24T08:48:00Z

On x86 a page without a mapper is by definition not referenced / old. The s390 architecture keeps the reference bit in the storage key and the current code will check the storage key for page without a mapper. This leads to an interesting effect: the first time an s390 system needs to write pages to swap it only finds referenced pages. This causes a lot of pages to get added and written to the swap device. To avoid this behaviour change page_referenced to query the storage key only if there is a mapper of the page. Signed-off-by: Martin Schwidefsky

fs: kill i_alloc_sem

2011-07-21T00:47:46Z

i_alloc_sem is a rather special rw_semaphore. It's the last one that may be released by a non-owner, and it's write side is always mirrored by real exclusion. It's intended use it to wait for all pending direct I/O requests to finish before starting a truncate. Replace it with a hand-grown construct: - exclusion for truncates is already guaranteed by i_mutex, so it can simply fall way - the reader side is replaced by an i_dio_count member in struct inode that counts the number of pending direct I/O requests. Truncate can't proceed as long as it's non-zero - when i_dio_count reaches non-zero we wake up a pending truncate using wake_up_bit on a new bit in i_flags - new references to i_dio_count can't appear while we are waiting for it to read zero because the direct I/O count always needs i_mutex (or an equivalent like XFS's i_iolock) for starting a new operation. This scheme is much simpler, and saves the space of a spinlock_t and a struct list_head in struct inode (typically 160 bits on a non-debug 64-bit system). Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

mm/memory-failure.c: fix spinlock vs mutex order

2011-06-28T01:00:13Z

We cannot take a mutex while holding a spinlock, so flip the order and fix the locking documentation. Signed-off-by: Peter Zijlstra Acked-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: avoid anon_vma_chain allocation under anon_vma lock

2011-06-18T02:24:11Z

Hugh Dickins points out that lockdep (correctly) spots a potential deadlock on the anon_vma lock, because we now do a GFP_KERNEL allocation of anon_vma_chain while doing anon_vma_clone(). The problem is that page reclaim will want to take the anon_vma lock of any anonymous pages that it will try to reclaim. So re-organize the code in anon_vma_clone() slightly: first do just a GFP_NOWAIT allocation, which will usually work fine. But if that fails, let's just drop the lock and re-do the allocation, now with GFP_KERNEL. End result: not only do we avoid the locking problem, this also ends up getting better concurrency in case the allocation does need to block. Tim Chen reports that with all these anon_vma locking tweaks, we're now almost back up to the spinlock performance. Reported-and-tested-by: Hugh Dickins Tested-by: Tim Chen Cc: Peter Zijlstra Cc: Andi Kleen Signed-off-by: Linus Torvalds

mm: avoid repeated anon_vma lock/unlock sequences in unlink_anon_vmas()

2011-06-18T02:23:52Z

This matches the anon_vma_clone() case, and uses the same lock helper functions. Because of the need to potentially release the anon_vma's, it's a bit more complex, though. We traverse the 'vma->anon_vma_chain' in two phases: the first loop gets the anon_vma lock (with the helper function that only takes the lock once for the whole loop), and removes any entries that don't need any more processing. The second phase just traverses the remaining list entries (without holding the anon_vma lock), and does any actual freeing of the anon_vma's that is required. Signed-off-by: Peter Zijlstra Tested-by: Hugh Dickins Tested-by: Tim Chen Cc: Andi Kleen Signed-off-by: Linus Torvalds