Messages in this thread |  | | Date | Tue, 10 Jul 2012 10:29:37 -0500 | | From | Seth Jennings <> | | Subject | Re: [PATCH 1/4] zsmalloc: remove x86 dependency |
| |
On 07/09/2012 09:21 PM, Minchan Kim wrote: > On 07/03/2012 06:15 AM, Seth Jennings wrote: <snip> >> +static void zs_copy_map_object(char *buf, struct page *firstpage, >> + int off, int size) > > firstpage is rather misleading. > As you know, we use firstpage term for real firstpage of zspage but > in case of zs_copy_map_object, it could be a middle page of zspage. > So I would like to use "page" instead of firstpage.
Accepted.
>> +{ >> + struct page *pages[2]; >> + int sizes[2]; >> + void *addr; >> + >> + pages[0] = firstpage; >> + pages[1] = get_next_page(firstpage); >> + BUG_ON(!pages[1]); >> + >> + sizes[0] = PAGE_SIZE - off; >> + sizes[1] = size - sizes[0]; >> + >> + /* disable page faults to match kmap_atomic() return conditions */ >> + pagefault_disable(); > > If I understand your intention correctly, you want to prevent calling > this function on non-atomic context. Right?
This is moved to zs_map_object() in a later patch, but the point is to provide uniform return conditions, regardless of whether the object to be mapped is contained in a single page or spans two pages. kmap_atomic() disables page faults, so I did it here to create symmetry. The result is that zs_map_object always returns with preemption and page faults disabled.
Also, Greg already merged these patches so I'll have to incorporate these changes as a separate patch.
Thanks, Seth
|  |