于 2013年02月06日 06:13, Andrew Morton 写道: > On Tue, 5 Feb 2013 14:26:40 -0500 > Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > >> On Wed, Feb 06, 2013 at 01:09:55AM +0800, Zhang Yanfei wrote: >>> Function nr_free_zone_pages, nr_free_buffer_pages and nr_free_pagecache_pages >>> are horribly badly named, they count present_pages - pages_high within zones >>> instead of free pages, so why not rename them to reasonable names, not cofusing >>> people. >>> >>> patch2 and patch3 are based on patch1. So please apply patch1 first. >>> >>> Zhang Yanfei (3): >>> mm: rename nr_free_zone_pages to nr_free_zone_high_pages >>> mm: rename nr_free_buffer_pages to nr_free_buffer_high_pages >>> mm: rename nr_free_pagecache_pages to nr_free_pagecache_high_pages >> >> I don't feel that this is an improvement. >> >> As you said, the "free" is already misleading, because those pages >> might all be allocated. "High" makes me think not just of highmem, >> but drug abuse in general. >> >> nr_available_*_pages? I don't know, but if we go through with all >> that churn, it had better improve something. > > Yes, those names are ghastly. > > Here's an idea: accurately document the functions with code comments. > Once this is done, that documentation may well suggest a good name ;) > As Johannes said, free is already misleading, so I think we should rename "free" at first. to "available"? I think it is ok. "high" here means those pages are above high watermark of a zone, not highmem or something else. So could I rename the functions to the names like nr_available_buffer_high_pages And accurately document them with code comments just as you suggested. is this ok? > > While we're there, please note that nr_free_buffer_pages() has a *lot* > of callers. Generally it's code which is trying to work out what is an > appropriate size for preallocated caching space, lookup tables, etc. > > That's a rather hopeless objective, given memory hotplug, mlock, etc. > But please do take a look at *why* these callers are calling > nr_free_buffer_pages() and let's ensure that both the implementation > and name are appropriate to their requirements. Yeah, it does have a lot callers and I think some of the callers are misusing the function from the comments. They always want to call the function to get lowmem pages. Thanks Zhang Yanfei -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href