Re: [Xen-devel] [PATCHv1 4/4] spinlock: add fair read-write locks

2016-01-18 Thread Jennifer Herbert
Hi Jan, Thank you for your comments. Sorry for the slow response - xmas and all... Responses below... On 22/12/15 13:54, Jan Beulich wrote: +/** + * rspin_until_writer_unlock - inc reader count & spin until writer is gone Stale comment - the function doesn't increment anything. Also through

Re: [Xen-devel] [PATCHv1 4/4] spinlock: add fair read-write locks

2015-12-22 Thread Jan Beulich
>>> On 18.12.15 at 15:09, wrote: > +/** > + * rspin_until_writer_unlock - inc reader count & spin until writer is gone Stale comment - the function doesn't increment anything. Also throughout the file, with Linux coding style converted to Xen style, comment style should be made Xen-like too. >

[Xen-devel] [PATCHv1 4/4] spinlock: add fair read-write locks

2015-12-18 Thread David Vrabel
From: Jennifer Herbert The current rwlocks are write-biased and unfair. This allows writers to starve readers in situations where there are many writers (e.g., p2m type changes from log dirty updates during domain save). Introduce queued read-write locks which use a fair spinlock (a ticket lock