On Mon, 18 Oct 2010 14:52:19 +0900 Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > On Mon, Oct 18, 2010 at 2:31 PM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > On Mon, 18 Oct 2010 14:18:52 +0900 > > Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > >> > > >> >> > + * > >> >> > + * Search an area of @size in the physical memory map and checks wheter > >> >> > >> >> Typo > >> >> whether > >> >> > >> >> > + * we can create a contigous free space. If it seems possible, try to > >> >> > + * create contigous space with page migration. If no_search==true, we just try > >> >> > + * to allocate [hint, hint+size) range of pages as contigous block. > >> >> > + * > >> >> > + * Returns a page of the beginning of contiguous block. At failure, NULL > >> >> > + * is returned. Each page in the area is set to page_count() = 1. Because > >> >> > >> >> Why do you mention page_count() = 1? > >> >> Do users of this function have to know it? > >> > > >> > A user can free any page within the range for his purpose. > >> > >> I think it's not a good idea if we allow handling of page by page, not > >> for page-chunk requested by user. > >> By mistake, free_contig_pages could have a trouble to free pages. > >> Why do you support the feature? ÂDo you have any motivation? > >> > > No big motivation. > > > > Usual pages are set up by prep_compund_page(page, order), but it is pages smaller > > than MAX_ORDER. ÂThen, I called prep_new_page() one by one. > > And I don't think some new prep_xxxx_page() is required. > > > > If you requests, ok, I'll add one. > > Maybe we are talking another thing. > > My question is why you noticed "page_count() == 1" in function description. > So your answer was for user to free some pages within big contiguous page. > Then, my concern is that if you didn't mentioned page_count() == 1 in > description, anonymous user will use just alloc_contig_pages and > free_contig_pages. That's enough for current our requirement. But > since you mentioned page_count() == 1 and you want for user to free > some pages within big contiguous page, anonymous user who isn't expert > in mm or careless people can free pages _freely_. It could make BUG > easily(free_contig_pages can free the page which is freed by user's > put_page). > > So if there isn't strong cause, I hope removing the mention for > preventing careless API usage. > Ah, ok. I see. I'll update that parts as "use free_contig_page() to free a chunk". Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>