- 26 Oct, 2010 40 commits
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Clemens Ladisch authored
Jaswinder Singh Rajput wrote: > By executing Documentation/timers/hpet_example.c > > for polling, I requested for 3 iterations but it seems iteration work > for only 2 as first expired time is always very small. > > # ./hpet_example poll /dev/hpet 10 3 > -hpet: executing poll > hpet_poll: info.hi_flags 0x0 > hpet_poll: expired time = 0x13 > hpet_poll: revents = 0x1 > hpet_poll: data 0x1 > hpet_poll: expired time = 0x1868c > hpet_poll: revents = 0x1 > hpet_poll: data 0x1 > hpet_poll: expired time = 0x18645 > hpet_poll: revents = 0x1 > hpet_poll: data 0x1 Clearing the HPET interrupt enable bit disables interrupt generation but does not disable the timer, so the interrupt status bit will still be set when the timer elapses. If another interrupt arrives before the timer has been correctly programmed (due to some other device on the same interrupt line, or CONFIG_DEBUG_SHIRQ), this results in an extra unwanted interrupt event because the status bit is likely to be set from comparator matches that happened before the device was opened. Therefore, we have to ensure that the interrupt status bit is and stays cleared until we actually program the timer. Signed-off-by:
Clemens Ladisch <clemens@ladisch.de> Reported-by:
Jaswinder Singh Rajput <jaswinderlinux@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Bob Picco <bpicco@redhat.com> Cc: <stable@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Jiri Slaby authored
When the initialization code in hpet finds a memory resource and does not find an IRQ, it does not unmap the memory resource previously mapped. There are buggy BIOSes which report resources exactly like this and what is worse the memory region bases point to normal RAM. This normally would not matter since the space is not touched. But when PAT is turned on, ioremap causes the page to be uncached and sets this bit in page->flags. Then when the page is about to be used by the allocator, it is reported as: BUG: Bad page state in process md5sum pfn:3ed00 page:ffffea0000dbd800 count:0 mapcount:0 mapping:(null) index:0x0 page flags: 0x20000001000000(uncached) Pid: 7956, comm: md5sum Not tainted 2.6.34-12-desktop #1 Call Trace: [<ffffffff810df851>] bad_page+0xb1/0x100 [<ffffffff810dfa45>] prep_new_page+0x1a5/0x1c0 [<ffffffff810dfe01>] get_page_from_freelist+0x3a1/0x640 [<ffffffff810e01af>] __alloc_pages_nodemask+0x10f/0x6b0 ... In this particular case: 1) HPET returns 3ed00000 as memory region base, but it is not in reserved ranges reported by the BIOS (excerpt): BIOS-e820: 0000000000100000 - 00000000af6cf000 (usable) BIOS-e820: 00000000af6cf000 - 00000000afdcf000 (reserved) 2) there is no IRQ resource reported by HPET method. On the other hand, the Intel HPET specs (1.0a) says (3.2.5.1): _CRS ( // Report 1K of memory consumed by this Timer Block memory range consumed // Optional: only used if BIOS allocates Interrupts [1] IRQs consumed ) [1] For case where Timer Block is configured to consume IRQ0/IRQ8 AND Legacy 8254/Legacy RTC hardware still exists, the device objects associated with 8254 & RTC devices should not report IRQ0/IRQ8 as "consumed resources". So in theory we should check whether if it is the case and use those interrupts instead. Anyway the address reported by the BIOS here is bogus, so non-presence of IRQ doesn't mean the "optional" part in point 2). Since I got no reply previously, fix this by simply unmapping the space when IRQ is not found and memory region was mapped previously. It would be probably more safe to walk the resources again and unmap appropriately depending on type. But as we now use only ioremap for both 2 memory resource types, it is not necessarily needed right now. Addresses https://bugzilla.novell.com/show_bug.cgi?id=629908Reported-by:
Olaf Hering <olaf@aepfle.de> Signed-off-by:
Jiri Slaby <jslaby@suse.cz> Acked-by:
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Bob Liu authored
Simple code for reducing list_empty(&source) check. Signed-off-by:
Bob Liu <lliubbo@gmail.com> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by:
Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Bob Liu authored
If not_managed is true all pages will be putback to lru, so break the loop earlier to skip other pages isolate. Signed-off-by:
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Bob Liu authored
__test_page_isolated_in_pageblock() returns 1 if all pages in the range are isolated, so fix the comment. Variable `pfn' will be initialised in the following loop so remove it. Signed-off-by:
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KAMEZAWA Hiroyuki authored
page_order() is called by memory hotplug's user interface to check the section is removable or not. (is_mem_section_removable()) It calls page_order() withoug holding zone->lock. So, even if the caller does if (PageBuddy(page)) ret = page_order(page) ... The caller may hit BUG_ON(). For fixing this, there are 2 choices. 1. add zone->lock. 2. remove BUG_ON(). is_mem_section_removable() is used for some "advice" and doesn't need to be 100% accurate. This is_removable() can be called via user program.. We don't want to take this important lock for long by user's request. So, this patch removes BUG_ON(). Signed-off-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Mel Gorman <mel@csn.ul.ie> Cc: <stable@kernel.org> Signed-off-by:
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Dean Nelson authored
Add missing spin_lock() of the page_table_lock before an error return in hugetlb_cow(). Callers of hugtelb_cow() expect it to be held upon return. Signed-off-by:
Dean Nelson <dnelson@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: <stable@kernel.org> Signed-off-by:
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Gleb Natapov authored
The vma returned by find_vma does not necessarily include the target address. If this happens the code tries to follow a page outside of any vma and returns ENOENT instead of EFAULT. Signed-off-by:
Gleb Natapov <gleb@redhat.com> Acked-by:
Christoph Lameter <cl@linux-foundation.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Kay Sievers authored
System management wants to subscribe to changes in swap configuration. Make /proc/swaps pollable like /proc/mounts. [akpm@linux-foundation.org: document proc_poll_event] Signed-off-by:
Kay Sievers <kay.sievers@vrfy.org> Acked-by:
Greg KH <greg@kroah.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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Dave Young authored
Add vzalloc() and vzalloc_node() to encapsulate the vmalloc-then-memset-zero operation. Use __GFP_ZERO to zero fill the allocated memory. Signed-off-by:
Dave Young <hidave.darkstar@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by:
Greg Ungerer <gerg@snapgear.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by:
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Andrew Morton authored
Reported-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:
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Andrew Morton authored
I had to go back to a 2.6.20 tree to work out why we're adding a number-of-inodes into a number-of-pages count. Restore the lost comment. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by:
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Namhyung Kim authored
Introduce ___GFP_* masks in order for gfp_t to not be mixed with plain integers which causes a lot of warnings like the following: warning: restricted gfp_t degrades to integer Signed-off-by:
Namhyung Kim <namhyung@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Namhyung Kim authored
This removes following warning from sparse: mm/vmstat.c:466:5: warning: symbol 'fragmentation_index' was not declared. Should it be static? [akpm@linux-foundation.org: move the include to top-of-file] Signed-off-by:
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Namhyung Kim authored
Declare 'bdi_pending_list' and 'tag_pages_for_writeback()' to remove following sparse warnings: mm/backing-dev.c:46:1: warning: symbol 'bdi_pending_list' was not declared. Should it be static? mm/page-writeback.c:825:6: warning: symbol 'tag_pages_for_writeback' was not declared. Should it be static? Signed-off-by:
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Namhyung Kim authored
s_start() and s_stop() grab/release vmlist_lock but were missing proper annotations. Add them. Signed-off-by:
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Namhyung Kim authored
Rename redundant 'tmp' to fix following sparse warnings: mm/vmalloc.c:296:34: warning: symbol 'tmp' shadows an earlier one mm/vmalloc.c:293:24: originally declared here Signed-off-by:
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Namhyung Kim authored
Make anon_vma_chain_free() static. It is called only in rmap.c and the corresponding alloc function is already static. Signed-off-by:
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Namhyung Kim authored
The page_check_address() conditionally grabs *@ptlp in case of returning non-NULL. Rename and wrap it using __cond_lock() removes following warnings from sparse: mm/rmap.c:472:9: warning: context imbalance in 'page_mapped_in_vma' - unexpected unlock mm/rmap.c:524:9: warning: context imbalance in 'page_referenced_one' - unexpected unlock mm/rmap.c:706:9: warning: context imbalance in 'page_mkclean_one' - unexpected unlock mm/rmap.c:1066:9: warning: context imbalance in 'try_to_unmap_one' - unexpected unlock Signed-off-by:
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Namhyung Kim authored
The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but page_unlock_anon_vma() releases them unconditionally. This leads sparse to complain about context imbalance. Annotate them. Signed-off-by:
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Namhyung Kim authored
The follow_pte() conditionally grabs *@ptlp in case of returning 0. Rename and wrap it using __cond_lock() removes following warnings: mm/memory.c:2337:9: warning: context imbalance in 'do_wp_page' - unexpected unlock mm/memory.c:3142:19: warning: context imbalance in 'handle_mm_fault' - different lock contexts for basic block Signed-off-by:
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Namhyung Kim authored
The do_wp_page() releases @ptl but was missing proper annotation. Add it. This removes following warnings from sparse: mm/memory.c:2337:9: warning: context imbalance in 'do_wp_page' - unexpected unlock mm/memory.c:3142:19: warning: context imbalance in 'handle_mm_fault' - different lock contexts for basic block Signed-off-by:
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Namhyung Kim authored
The get_locked_pte() conditionally grabs 'ptl' in case of returning non-NULL. This leads sparse to complain about context imbalance. Rename and wrap it using __cond_lock() to make sparse happy. Signed-off-by:
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Namhyung Kim authored
This removes following warning from sparse: mm/page_alloc.c:1934:9: warning: restricted gfp_t degrades to integer Signed-off-by:
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Namhyung Kim authored
'end' shadows earlier one and is not necessary at all. Remove it and use 'pos' instead. This removes following sparse warnings: mm/filemap.c:2180:24: warning: symbol 'end' shadows an earlier one mm/filemap.c:2132:25: originally declared here Signed-off-by:
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Michel Lespinasse authored
access_error() already takes error_code as an argument, so there is no need for an additional write flag. Signed-off-by:
Michel Lespinasse <walken@google.com> Acked-by:
Rik van Riel <riel@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by:
"H. Peter Anvin" <hpa@zytor.com> Signed-off-by:
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Michel Lespinasse authored
This change reduces mmap_sem hold times that are caused by waiting for disk transfers when accessing file mapped VMAs. It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call site wants mmap_sem to be released if blocking on a pending disk transfer. In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and do_page_fault() will then re-acquire mmap_sem and retry the page fault. It is expected that the retry will hit the same page which will now be cached, and thus it will complete with a low mmap_sem hold time. Tests: - microbenchmark: thread A mmaps a large file and does random read accesses to the mmaped area - achieves about 55 iterations/s. Thread B does mmap/munmap in a loop at a separate location - achieves 55 iterations/s before, 15000 iterations/s after. - We are seeing related effects in some applications in house, which show significant performance regressions when running without this change. [akpm@linux-foundation.org: fix warning & crash] Signed-off-by:
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Michel Lespinasse authored
Introduce a single location where filemap_fault() locks the desired page. There used to be two such places, depending if the initial find_get_page() was successful or not. Signed-off-by:
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Richard Kennedy authored
Reorder structure anon_vma to remove alignment padding on 64 builds when (CONFIG_KSM || CONFIG_MIGRATION). This will shrink the size of the anon_vma structure from 40 to 32 bytes & allow more objects per slab in its kmem_cache. Under slub the objects in the anon_vma kmem_cache will then be 40 bytes with 102 objects per slab. (On v2.6.36 without this patch,the size is 48 bytes and 85 objects/slab.) Signed-off-by:
Richard Kennedy <richard@rsk.demon.co.uk> Reviewed-by:
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Dima Zavin authored
Buggy drivers (e.g. fsl_udc) could call dma_pool_alloc from atomic context with GFP_KERNEL. In most instances, the first pool_alloc_page call would succeed and the sleeping functions would never be called. This allowed the buggy drivers to slip through the cracks. Add a might_sleep_if() checking for __GFP_WAIT in flags. Signed-off-by:
Dima Zavin <dima@android.com> Signed-off-by:
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Peter Zijlstra authored
Document outlining some of the highmem issues, started by me, edited by David. Signed-off-by:
David Howells <dhowells@redhat.com> Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:
Chris Metcalf <cmetcalf@tilera.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Miller <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by:
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Peter Zijlstra authored
Now that the KM_type stuff is history, clean up the compiler warning. Signed-off-by:
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Peter Zijlstra authored
Since we no longer need to provide KM_type, the whole pte_*map_nested() API is now redundant, remove it. Signed-off-by:
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Peter Zijlstra authored
Keep the current interface but ignore the KM_type and use a stack based approach. The advantage is that we get rid of crappy code like: #define __KM_PTE \ (in_nmi() ? KM_NMI_PTE : \ in_irq() ? KM_IRQ_PTE : \ KM_PTE0) and in general can stop worrying about what context we're in and what kmap slots might be appropriate for that. The downside is that FRV kmap_atomic() gets more expensive. For now we use a CPP trick suggested by Andrew: #define kmap_atomic(page, args...) __kmap_atomic(page) to avoid having to touch all kmap_atomic() users in a single patch. [ not compiled on: - mn10300: the arch doesn't actually build with highmem to begin with ] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c] Acked-by:
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Peter Zijlstra authored
Ensure kmap_atomic() usage is strictly nested Signed-off-by:
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KOSAKI Motohiro authored
When a page has PG_referenced, shrink_page_list() discards it only if it is not dirty. This rule works fine if the backing filesystem is a regular one. PG_dirty is a good signal that the page was used recently because the flusher threads clean pages periodically. In addition, page writeback is costlier than simple page discard. However, when a page is on tmpfs this heuristic doesn't work because flusher threads don't write back tmpfs pages. Consequently tmpfs pages always rotate around the lru twice at least and adds unnecessary lru churn. Simple tmpfs streaming io shouldn't cause large anonymous page swap-out. Remove this unncessary reclaim bonus of tmpfs pages. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Reviewed-by:
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Wu Fengguang authored
The dirty_ratio was silently limited in global_dirty_limits() to >= 5%. This is not a user expected behavior. And it's inconsistent with calc_period_shift(), which uses the plain vm_dirty_ratio value. Let's remove the internal bound. At the same time, fix balance_dirty_pages() to work with the dirty_thresh=0 case. This allows applications to proceed when dirty+writeback pages are all cleaned. And ">" fits with the name "exceeded" better than ">=" does. Neil thinks it is an aesthetic improvement as well as a functional one :) Signed-off-by:
Con Kolivas <kernel@kolivas.org> Acked-by:
Neil Brown <neilb@suse.de> Reviewed-by:
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Mel Gorman authored
writeback: do not sleep on the congestion queue if there are no congested BDIs or if significant congestion is not being encountered in the current zone If congestion_wait() is called with no BDI congested, the caller will sleep for the full timeout and this may be an unnecessary sleep. This patch adds a wait_iff_congested() that checks congestion and only sleeps if a BDI is congested else, it calls cond_resched() to ensure the caller is not hogging the CPU longer than its quota but otherwise will not sleep. This is aimed at reducing some of the major desktop stalls reported during IO. For example, while kswapd is operating, it calls congestion_wait() but it could just have been reclaiming clean page cache pages with no congestion. Without this patch, it would sleep for a full timeout but after this patch, it'll just call schedule() if it has been on the CPU too long. Similar logic applies to direct reclaimers that are not making enough progress. Signed-off-by:
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KOSAKI Motohiro authored
isolate_lru_pages() does not just isolate LRU tail pages, but also isolates neighbour pages of the eviction page. The neighbour search does not stop even if neighbours cannot be isolated which is excessive as the lumpy reclaim will no longer result in a successful higher order allocation. This patch stops the PFN neighbour pages if an isolation fails and moves on to the next block. Signed-off-by:
Minchan Kim <minchan.kim@gmail.com> Reviewed-by:
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KOSAKI Motohiro authored
After synchrounous lumpy reclaim, the page_list is guaranteed to not have active pages as page activation in shrink_page_list() disables lumpy reclaim. Remove the dead code. Signed-off-by:
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