| Date | Thu, 25 May 2006 07:38:02 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 08/33] readahead: common macros |
| |
Wu Fengguang <wfg@mail.ustc.edu.cn> wrote: > > On Thu, May 25, 2006 at 03:56:24PM +1000, Nick Piggin wrote: > > >+#define PAGES_BYTE(size) (((size) + PAGE_CACHE_SIZE - 1) >> > > >PAGE_CACHE_SHIFT) > > >+#define PAGES_KB(size) PAGES_BYTE((size)*1024) > > > > > Don't really like the names. Don't think they do anything for clarity, but > > if you can come up with something better for PAGES_BYTE I might change my > > mind ;) (just forget about PAGES_KB - people know what *1024 means) > > > > Also: the replacements are wrong: if you've defined VM_MAX_READAHEAD to be > > 4095 bytes, you don't want the _actual_ readahead to be 4096 bytes, do you? > > It is saying nothing about minimum, so presumably 0 is the correct choice. > > Got an idea, how about these ones: > > #define FULL_PAGES(bytes) ((bytes) >> PAGE_CACHE_SHIFT)
I dunno. We've traditionally open-coded things like this.
> #define PARTIAL_PAGES(bytes) (((bytes)+PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
That's identical to include/linux/kernel.h:DIV_ROUND_UP(), from the gfs2 tree. - 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/
|