Messages in this thread Patch in this message | | | Date | Sun, 7 Jul 2002 21:07:45 +0000 | From | Justin Guyett <> | Subject | [PATCH] Doc/fs/proc.txt (bdflush) for 2.4.19-rc |
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This updates the vm/bdflush description to accurately reflect the values in /proc. The descriptions won't win any prizes, but at least the variable table is correct.
--- linux-2.4.19-rc1/Documentation/filesystems/proc.txt Sun Jul 7 20:40:04 2002 +++ linux-2.4.19-rc1-new/Documentation/filesystems/proc.txt Sun Jul 7 20:46:36 2002 @@ -961,17 +961,17 @@ Table 2-2: Parameters in /proc/sys/vm/bdflush .............................................................................. - Value Meaning - 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 - dummy Unused + Value Meaning + ----- ------- + nfract Percentage of buffer cache dirty to activate bdflush + ndirty Maximum number of dirty blocks to write out per wake-cycle + dummy Unused + dummy Unused + interval Time 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 Percentage of buffer cache dirty to stop bdflush + dummy Unused .............................................................................. nfract @@ -991,29 +991,25 @@ 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 -------- +interval +-------- -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. +Interval specifies the time in jiffies (clockticks) between kupdated flushes. +The default number of jiffies per second is 100. -nref_dirt ---------- +age_buffer +---------- -When refill_freelist() comes across more than nref_dirt dirty buffers, it will -wake up bdflush. +Age_buffer specifies the maximum time Linux waits before writing out a dirty +buffer to disk. The value is expressed in jiffies (clockticks) and the default +number of jiffies per second is 100. Age_buffer is the maximum age for data +blocks. -age_buffer and age_super ------------------------- +nfract_sync and nfract_stop_bdflush +----------------------------------- -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. +These follow the same general rules as nfract above, but values specify limits +determining when synchronous flushing starts and flushing ends, respectively. buffermem --------- - 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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