patch-2.4.21 linux-2.4.21/Documentation/filesystems/proc.txt
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- Lines: 92
- Date:
2003-06-13 07:51:29.000000000 -0700
- Orig file:
linux-2.4.20/Documentation/filesystems/proc.txt
- Orig date:
2002-11-28 15:53:08.000000000 -0800
diff -urN linux-2.4.20/Documentation/filesystems/proc.txt linux-2.4.21/Documentation/filesystems/proc.txt
@@ -952,15 +952,14 @@
Table 2-2: Parameters in /proc/sys/vm/bdflush
..............................................................................
Value Meaning
- nfract Percentage of buffer cache dirty to activate bdflush
+ nfract Percentage of buffer cache dirty to activate bdflush
ndirty Maximum number of dirty blocks to write out per wake-cycle
- nrefill Number of clean buffers to try to obtain each time we call refill
- nref_dirt buffer threshold for activating bdflush when trying to refill
- buffers.
dummy Unused
- age_buffer Time for normal buffer to age before we flush it
- age_super Time for superblock to age before we flush it
dummy Unused
+ interval jiffies delay between kupdate flushes
+ age_buffer Time for normal buffer to age before we flush it
+ nfract_sync Percentage of buffer cache dirty to activate bdflush synchronously
+ nfract_stop_bdflush Percetange of buffer cache dirty to stop bdflush
dummy Unused
..............................................................................
@@ -974,6 +973,12 @@
long time, but it also means that it will have to do a lot of I/O at once when
memory becomes short. A lower value will spread out disk I/O more evenly.
+interval
+--------
+
+The interval between two kupdate runs. The value is expressed in
+jiffies (clockticks), the number of jiffies per second is 100.
+
ndirty
------
@@ -981,29 +986,18 @@
disk at one time. A high value will mean delayed, bursty I/O, while a small
value can lead to memory shortage when bdflush isn't woken up often enough.
-nrefill
--------
-
-This is the number of buffers that bdflush will add to the list of free
-buffers when refill_freelist() is called. It is necessary to allocate free
-buffers beforehand, since the buffers are often different sizes than the
-memory pages and some bookkeeping needs to be done beforehand. The higher the
-number, the more memory will be wasted and the less often refill_freelist()
-will need to run.
-
-nref_dirt
----------
+age_buffer
+----------
-When refill_freelist() comes across more than nref_dirt dirty buffers, it will
-wake up bdflush.
+Finally, the age_buffer parameter govern the maximum time Linux
+waits before writing out a dirty buffer to disk. The value is expressed in
+jiffies (clockticks), the number of jiffies per second is 100.
-age_buffer and age_super
-------------------------
+nfract_sync
+-----------
-Finally, the age_buffer and age_super parameters govern the maximum time Linux
-waits before writing out a dirty buffer to disk. The value is expressed in
-jiffies (clockticks), the number of jiffies per second is 100. Age_buffer is
-the maximum age for data blocks, while age_super is for filesystems meta data.
+nfract_stop_bdflush
+-------------------
buffermem
---------
@@ -1582,10 +1576,14 @@
error_burst and error_cost
--------------------------
-These parameters are used to limit the warning messages written to the kernel
-log from the routing code. The higher the error_cost factor is, the fewer
-messages will be written. Error_burst controls when messages will be dropped.
-The default settings limit warning messages to one every five seconds.
+These parameters are used to limit how many ICMP destination unreachable to
+send from the host in question. ICMP destination unreachable messages are
+sent when we can not reach the next hop, while trying to transmit a packet.
+It will also print some error messages to kernel logs if someone is ignoring
+our ICMP redirects. The higher the error_cost factor is, the fewer
+destination unreachable and error messages will be let through. Error_burst
+controls when destination unreachable messages and error messages will be
+dropped. The default settings limit warning messages to five every second.
flush
-----
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