Messages in this thread Patch in this message | | | From | James Simmons <> | Subject | [PATCH 58/60] staging: lustre: osc: avoid 64 divide in osc_cache_too_much | Date | Sat, 28 Jan 2017 19:05:26 -0500 |
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The use of 64 bit time introduces an expensive 64 bit division operation. Since the time lapse being calculated in osc_cache_too_much will never be more than seventy years we can cast the time lapse to an long and perform a normal 32 bit divison operation instead.
Signed-off-by: James Simmons <uja.ornl@yahoo.com> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8835 Reviewed-on: https://review.whamcloud.com/23814 Reviewed-by: Andreas Dilger <andreas.dilger@intel.com> Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com> Signed-off-by: James Simmons <jsimmons@infradead.org> --- drivers/staging/lustre/lustre/osc/osc_page.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/lustre/lustre/osc/osc_page.c b/drivers/staging/lustre/lustre/osc/osc_page.c index 0461408..ab9d0d7 100644 --- a/drivers/staging/lustre/lustre/osc/osc_page.c +++ b/drivers/staging/lustre/lustre/osc/osc_page.c @@ -370,12 +370,17 @@ static int osc_cache_too_much(struct client_obd *cli) return lru_shrink_min(cli); } else { time64_t duration = ktime_get_real_seconds(); + long timediff; /* knock out pages by duration of no IO activity */ duration -= cli->cl_lru_last_used; - duration >>= 6; /* approximately 1 minute */ - if (duration > 0 && - pages >= div64_s64((s64)budget, duration)) + /* + * The difference shouldn't be more than 70 years + * so we can safely case to a long. Round to + * approximately 1 minute. + */ + timediff = (long)(duration >> 6); + if (timediff > 0 && pages >= budget / timediff) return lru_shrink_min(cli); } return 0; -- 1.8.3.1
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