Re: [PATCH 4/6] mm/gup: track gup-pinned pages

2019-02-20 Thread John Hubbard
On 2/20/19 11:24 AM, Ira Weiny wrote: On Sun, Feb 03, 2019 at 09:21:33PM -0800, john.hubb...@gmail.com wrote: From: John Hubbard [snip] + * + * Locking: the lockless algorithm described in page_cache_gup_pin_speculative() + * and page_cache_gup_pin_speculative() provides safe operation for

Re: [PATCH 4/6] mm/gup: track gup-pinned pages

2019-02-20 Thread Ira Weiny
On Sun, Feb 03, 2019 at 09:21:33PM -0800, john.hubb...@gmail.com wrote: > From: John Hubbard > [snip] > > +/* > + * GUP_PIN_COUNTING_BIAS, and the associated functions that use it, overload > + * the page's refcount so that two separate items are tracked: the original > page > + * reference

Re: [PATCH 4/6] mm/gup: track gup-pinned pages

2019-02-04 Thread John Hubbard
On 2/4/19 10:19 AM, Matthew Wilcox wrote: > On Sun, Feb 03, 2019 at 09:21:33PM -0800, john.hubb...@gmail.com wrote: >> +/* >> + * GUP_PIN_COUNTING_BIAS, and the associated functions that use it, overload >> + * the page's refcount so that two separate items are tracked: the original >> page >> +

Re: [PATCH 4/6] mm/gup: track gup-pinned pages

2019-02-04 Thread Matthew Wilcox
On Sun, Feb 03, 2019 at 09:21:33PM -0800, john.hubb...@gmail.com wrote: > +/* > + * GUP_PIN_COUNTING_BIAS, and the associated functions that use it, overload > + * the page's refcount so that two separate items are tracked: the original > page > + * reference count, and also a new count of how