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Date: Mon, 29 Oct 2012 12:30:48 +0800
From: zwu.kernel@...il.com
To: linux-fsdevel@...r.kernel.org
Cc: linux-ext4@...r.kernel.org, linux-btrfs@...r.kernel.org,
linux-kernel@...r.kernel.org, linuxram@...ux.vnet.ibm.com,
viro@...iv.linux.org.uk, david@...morbit.com, tytso@....edu,
cmm@...ibm.com, wuzhy@...ux.vnet.ibm.com, wenqing.lz@...bao.com
Subject: [RFC v4+ hot_track 06/19] vfs: add temp calculation function
From: Zhi Yong Wu <wuzhy@...ux.vnet.ibm.com>
Signed-off-by: Zhi Yong Wu <wuzhy@...ux.vnet.ibm.com>
---
fs/hot_tracking.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 74 insertions(+), 0 deletions(-)
diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 0a603a1..83e590c 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -323,6 +323,80 @@ static void hot_freq_data_update(struct hot_freq_data *freq_data, bool write)
}
}
+static u64 hot_raw_shift(u64 counter, u32 bits, bool dir)
+{
+ if (dir)
+ return counter << bits;
+ else
+ return counter >> bits;
+}
+
+/*
+ * hot_temp_calc() is responsible for distilling the six heat
+ * criteria down into a single temperature value for the data,
+ * which is an integer between 0 and HEAT_MAX_VALUE.
+ */
+static u32 hot_temp_calc(struct hot_freq_data *freq_data)
+{
+ u32 result = 0;
+
+ struct timespec ckt = current_kernel_time();
+ u64 cur_time = timespec_to_ns(&ckt);
+
+ u32 nrr_heat = (u32)hot_raw_shift((u64)freq_data->nr_reads,
+ NRR_MULTIPLIER_POWER, true);
+ u32 nrw_heat = (u32)hot_raw_shift((u64)freq_data->nr_writes,
+ NRW_MULTIPLIER_POWER, true);
+
+ u64 ltr_heat =
+ hot_raw_shift((cur_time - timespec_to_ns(&freq_data->last_read_time)),
+ LTR_DIVIDER_POWER, false);
+ u64 ltw_heat =
+ hot_raw_shift((cur_time - timespec_to_ns(&freq_data->last_write_time)),
+ LTW_DIVIDER_POWER, false);
+
+ u64 avr_heat =
+ hot_raw_shift((((u64) -1) - freq_data->avg_delta_reads),
+ AVR_DIVIDER_POWER, false);
+ u64 avw_heat =
+ hot_raw_shift((((u64) -1) - freq_data->avg_delta_writes),
+ AVW_DIVIDER_POWER, false);
+
+ /* ltr_heat is now guaranteed to be u32 safe */
+ if (ltr_heat >= hot_raw_shift((u64) 1, 32, true))
+ ltr_heat = 0;
+ else
+ ltr_heat = hot_raw_shift((u64) 1, 32, true) - ltr_heat;
+
+ /* ltw_heat is now guaranteed to be u32 safe */
+ if (ltw_heat >= hot_raw_shift((u64) 1, 32, true))
+ ltw_heat = 0;
+ else
+ ltw_heat = hot_raw_shift((u64) 1, 32, true) - ltw_heat;
+
+ /* avr_heat is now guaranteed to be u32 safe */
+ if (avr_heat >= hot_raw_shift((u64) 1, 32, true))
+ avr_heat = (u32) -1;
+
+ /* avw_heat is now guaranteed to be u32 safe */
+ if (avw_heat >= hot_raw_shift((u64) 1, 32, true))
+ avw_heat = (u32) -1;
+
+ nrr_heat = (u32)hot_raw_shift((u64)nrr_heat,
+ (3 - NRR_COEFF_POWER), false);
+ nrw_heat = (u32)hot_raw_shift((u64)nrw_heat,
+ (3 - NRW_COEFF_POWER), false);
+ ltr_heat = hot_raw_shift(ltr_heat, (3 - LTR_COEFF_POWER), false);
+ ltw_heat = hot_raw_shift(ltw_heat, (3 - LTW_COEFF_POWER), false);
+ avr_heat = hot_raw_shift(avr_heat, (3 - AVR_COEFF_POWER), false);
+ avw_heat = hot_raw_shift(avw_heat, (3 - AVW_COEFF_POWER), false);
+
+ result = nrr_heat + nrw_heat + (u32) ltr_heat +
+ (u32) ltw_heat + (u32) avr_heat + (u32) avw_heat;
+
+ return result;
+}
+
/*
* Initialize inode and range map arrays.
*/
--
1.7.6.5
--
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