Messages in this thread |  | | | Date | Tue, 24 Jul 2007 12:32:15 +0800 | | From | Fengguang Wu <> | | Subject | Re: [PATCH 03/10] readahead: combine file_ra_state.prev_index/prev_offset into prev_pos |
| |
On Mon, Jul 23, 2007 at 08:55:35PM -0700, Andrew Morton wrote: > On Tue, 24 Jul 2007 10:00:12 +0800 Fengguang Wu <wfg@mail.ustc.edu.cn> wrote: > > > @@ -342,11 +342,9 @@ ondemand_readahead(struct address_space > > bool hit_readahead_marker, pgoff_t offset, > > unsigned long req_size) > > { > > - int max; /* max readahead pages */ > > - int sequential; > > - > > - max = ra->ra_pages; > > - sequential = (offset - ra->prev_index <= 1UL) || (req_size > max); > > + int max = ra->ra_pages; /* max readahead pages */ > > + pgoff_t prev_offset; > > + int sequential; > > > > /* > > * It's the expected callback offset, assume sequential access. > > @@ -360,6 +358,9 @@ ondemand_readahead(struct address_space > > goto readit; > > } > > > > + prev_offset = ra->prev_pos >> PAGE_CACHE_SHIFT; > > + sequential = offset - prev_offset <= 1UL || req_size > max; > > It's a bit pointless using an opaque type for prev_offset here, and then > encoding the knowledge that it is implemented as "unsigned long". > > It's a minor thing, but perhaps just "<= 1" would make more sense here.
Yeah, "<= 1" is OK. But the expression still requires pgoff_t to be 'unsigned' to work correctly.
So what about "<= 1U"?
- 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/
|  |