Messages in this thread Patch in this message | | | Date | Tue, 25 Jan 2005 14:59:17 +0300 | From | Oleg Nesterov <> | Subject | [PATCH 3/4] cleanup ahead window calculation |
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This patch moves some code into the get_next_ra_size() and renames it into 'set_next_ahead_window'.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 2.6.11-rc2/mm/readahead.c~ 2005-01-25 15:17:13.000000000 +0300 +++ 2.6.11-rc2/mm/readahead.c 2005-01-25 16:51:50.000000000 +0300 @@ -85,20 +85,23 @@ static unsigned long get_init_ra_size(un * not for each call to readahead. If a cache miss occured, reduce next I/O * size, else increase depending on how close to max we are. */ -static unsigned long get_next_ra_size(unsigned long cur, unsigned long max, - unsigned long min, unsigned long * flags) +static void set_next_ahead_window(struct file_ra_state *ra, + unsigned long max, unsigned long min) { unsigned long newsize; + unsigned long cur = ra->size; - if (*flags & RA_FLAG_MISS) { + ra->ahead_start = ra->start + cur; + + if (ra->flags & RA_FLAG_MISS) { + ra->flags &= ~RA_FLAG_MISS; newsize = max((cur - 2), min); - *flags &= ~RA_FLAG_MISS; - } else if (cur < max / 16) { + } else if (cur < max / 16) newsize = 4 * cur; - } else { + else newsize = 2 * cur; - } - return min(newsize, max); + + ra->ahead_size = min(newsize, max); } #define list_to_page(head) (list_entry((head)->prev, struct page, lru)) @@ -457,9 +460,7 @@ page_cache_readahead(struct address_spac * immediately. */ if (req_size >= max) { - ra->ahead_size = get_next_ra_size(ra->size, max, min, - &ra->flags); - ra->ahead_start = ra->start + ra->size; + set_next_ahead_window(ra, max, min); blockable_page_cache_readahead(mapping, filp, ra->ahead_start, ra->ahead_size, ra, 1); } @@ -497,9 +498,7 @@ page_cache_readahead(struct address_spac ra->size = ra->ahead_size; } - ra->ahead_size = get_next_ra_size(ra->size, max, min, - &ra->flags); - ra->ahead_start = ra->start + ra->size; + set_next_ahead_window(ra, max, min); block = ((offset + newsize - 1) >= ra->ahead_start); if (!blockable_page_cache_readahead(mapping, filp, - 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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