Messages in this thread | | | Date | Sun, 16 Oct 2005 12:59:53 +0100 (IST) | From | Mel Gorman <> | Subject | Re: [PATCH 0/8] Fragmentation Avoidance V17 |
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On Sat, 15 Oct 2005, Paul Jackson wrote:
> Mel wrote: > > +#define __GFP_USER 0x80000u /* User and other easily reclaimed pages */ > > +#define __GFP_KERNRCLM 0x100000u /* Kernel page that is reclaimable */ > > Sorry, but that __GFP_USER name is still sticking in my craw. > > I won't try to reopen my quest to get it named __GFP_REALLY_REALLY_EASY_RCLM > or whatever it was, but instead will venture on a new quest. > > Can we get the 'RCLM' in there. Especially since this term appears > naked in such code as: >
__GFP_USERRCLM is the original name and the motivation for changing it to __GFP_USER no longer exists. However, __GFP_EASYRCLM would also make sense as it flags pages that are (surprise surprise) easily reclaimed. Would __GFP_EASYRCLM be the best choice? __GFP_USERRCLM may imply to some readers that it is reclaimed by the user somehow. The flags would then be;
__GFP_EASYRCLM - Allocations for pages that are easily reclaimed such as userspace and buffer pages
__GFP_KERNRCLM - Allocations for pages that may be reclaimed by the kernel such as caches
No flag - Page cannot be easily reclaimed by any mechanism.
I would be happy with __GFP_USERRCLM but __GFP_EASYRCLM may be more obvious?
> > - page = alloc_page(GFP_HIGHUSER); > > + page = alloc_page(GFP_HIGHUSER|__GFP_USER); > > where it is not at all obvious to the reader of this file (fs/exec.c) > that the __GFP_USER term is commenting on the reclaim behaviour of > the page to be allocated. > > I'd be happier with: > > > +#define __GFP_USERRCLM 0x80000u /* User and other easily reclaimed pages */ > > +#define __GFP_KERNRCLM 0x100000u /* Kernel page that is reclaimable */ > > and: > > > - page = alloc_page(GFP_HIGHUSER); > > + page = alloc_page(GFP_HIGHUSER|__GFP_USERRCLM); > > Also the bold assymetry of these two #defines seems to be without motivation, > one with the 'RCLM', and the other with ' ' four spaces. > >
-- Mel Gorman Part-time Phd Student Java Applications Developer University of Limerick IBM Dublin Software Lab - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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