x86 rwsem: down_read_critical implementation
Michel Lespinasse <walken(a)google.com> wrote: The basic properties that have been true so far still hold: - RWSEM_ACTIVE_READ_BIAS & RWSEM_ACTIVE_MASK == 1 - RWSEM_ACTIVE_WRITE_BIAS & RWSEM_ACTIVE_MASK == 1 - RWSEM_WAITING_BIAS & RWSEM_ACTIVE_MASK == 0 - RWSEM_ACTIVE_WRITE_BIAS < 0 and RWSEM_WAITI... 19 May 2010 11:33
Fix possible NULL pointer dereference in print_IO_APIC
On Tue, 18 May 2010, Jeremy Fitzhardinge wrote: On 05/18/2010 03:23 AM, Stefano Stabellini wrote: Make sure chip_data is not NULL before accessing it. You should clarify under what circumstances it can be legitimately NULL. The VIRQ_TIMER handler and virq handlers in general don't have... 19 May 2010 11:33
[PATCH 5/4] Provide __dma_aligned macro
Commit 3843384a055496dfed3c93ae883d964d8290fdab ("Input: ad7877 - keep dma rx buffers in seperate cache lines")[sic] introduced the use of ____cacheline_aligned to ensure that buffers used for DMA as part of a structure were suitably separated from the rest of the structure. However, aligning to the cache line si... 19 May 2010 10:26
kvm: network problem with Solaris 10u8 guest
Hi folks, I am trying to run Solaris 10u8 as a guest in kvm (kernel Problem: The virtual network devices don't work with this Solaris version. e1000 and pcnet work just by chance, as it seems. I can ping the guest (even though some packets are lost). I cannot use ssh to login. rtl8139 and ne2k_p... 19 May 2010 16:01
mm: Move ARCH_SLAB_MINALIGN and ARCH_KMALLOC_MINALIGN to <linux/slab_def.h>
Hi, I have some comments/questions, I hope it's not too silly: On Wed, May 19, 2010 at 12:01:42PM +0100, David Woodhouse wrote: +#ifndef ARCH_KMALLOC_MINALIGN +/* + * Enforce a minimum alignment for the kmalloc caches. + * Usually, the kmalloc caches are cache_line_size() aligned, except when + * D... 19 May 2010 16:01
generic rwsem: implement down_read_critical() / up_read_critical()
Michel Lespinasse <walken(a)google.com> wrote: +void __sched down_read_critical(struct rw_semaphore *sem) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); + + LOCK_CONTENDED(sem, __down_read_trylock, __down_read_unfair); + + preempt_disable(); Shouldn't preemption real... 19 May 2010 10:26
schedule: simplify the reacquire_kernel_lock() logic
On Wed, May 19, 2010 at 02:57:11PM +0200, Oleg Nesterov wrote: - Contrary to what 6d558c3a says, there is no need to reload prev = rq->curr after the context switch. You always schedule back to where you came from, prev must be equal to current even if cpu/rq was changed. - This also means reac... 19 May 2010 09:20
logfs: kill BKL
On Tue, Apr 27, 2010 at 10:30:06PM +0200, Arnd Bergmann wrote: logfs does not need the BKL, so use ->unlocked_ioctl instead of ->ioctl in file operations. --- On Tuesday 27 April 2010 22:12:52 Frederic Weisbecker wrote: I've applied this series in bkl/ioctl, it passed allyesconfig in sparc. ... 19 May 2010 09:20
rwsem: let RWSEM_WAITING_BIAS represent any number of waiting threads
Michel Lespinasse <walken(a)google.com> wrote: Previously each waiting thread added a bias of RWSEM_WAITING_BIAS. With this change, the bias is added only once when the wait list is non-empty. You might want to change "when the wait list" to "to indicate that the wait list". But apart from that: Acked-by:... 19 May 2010 09:20
rwsem: lighter active count checks when waking up readers
Michel Lespinasse <walken(a)google.com> wrote: ... When there are waiter threads on a rwsem and the spinlock is held, other threads can only increment the active count by trying to grab the rwsem in up_xxxx(). That's not true. A thread attempting to get an rwsem by issuing a down_read() or down_write() wi... 21 May 2010 05:08