| Message ID | 20220405082357.22606-1-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/vmscan: reorder scan_balance definition to simplify the scan type check | expand |
On Tue, Apr 05, 2022 at 08:23:57AM +0000, Wei Yang wrote: > Even is_file_lru() return bool type, we leverage it as an index for anon > or file. > > With this in hand, after reorder scan_balance definition, we can compare > directly between scan_balance and file to get the exclusive scan type. > > After this, the code looks more readable and save some instructions. This scares me. I would not apply this patch.
On Tue, Apr 05, 2022 at 01:30:26PM +0100, Matthew Wilcox wrote: >On Tue, Apr 05, 2022 at 08:23:57AM +0000, Wei Yang wrote: >> Even is_file_lru() return bool type, we leverage it as an index for anon >> or file. >> >> With this in hand, after reorder scan_balance definition, we can compare >> directly between scan_balance and file to get the exclusive scan type. >> >> After this, the code looks more readable and save some instructions. > >This scares me. I would not apply this patch. Because?
diff --git a/mm/vmscan.c b/mm/vmscan.c index 89745cf34386..0b7cc9309e70 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2638,10 +2638,10 @@ static bool inactive_is_low(struct lruvec *lruvec, enum lru_list inactive_lru) } enum scan_balance { - SCAN_EQUAL, - SCAN_FRACT, SCAN_ANON, SCAN_FILE, + SCAN_EQUAL, + SCAN_FRACT, }; /* @@ -2838,7 +2838,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, case SCAN_FILE: case SCAN_ANON: /* Scan one type exclusively */ - if ((scan_balance == SCAN_FILE) != file) + if (scan_balance != file) scan = 0; break; default:
Even is_file_lru() return bool type, we leverage it as an index for anon or file. With this in hand, after reorder scan_balance definition, we can compare directly between scan_balance and file to get the exclusive scan type. After this, the code looks more readable and save some instructions. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> CC: Johannes Weiner <hannes@cmpxchg.org> CC: Mel Gorman <mgorman@suse.de> --- mm/vmscan.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)