Re: [PATCH 1/2] batch-write.patch

[Hans Reiser <reiser@namesys.com>]

Pekka Enberg wrote:

> On 7/4/06, Vladimir V. Saveliev <vs@namesys.com> wrote:
>
>> @@ -784,6 +786,8 @@ otherwise noted.
>>
>>    writev: called by the writev(2) system call
>>
>> +  batch_write: optional, if implemented called by writev(2) and
>> write(2)
>> +
>
>
> It'd be nice if you added some explanation here why a filesystem
> developer would want to implement it.
>
>                                       Pekka
>
>
Vladimir, it sounds like he found another place you might insert this
comment:

+/*
+ * When calling the filesystem for writes, there is processing
+ * that must be done:
+ * 1) per word
+ * 2) per page
+ * 3) per call to the FS
+ * If the FS is called per page, then it turns out that 3) costs more
+ * than 1) and 2) for sophisticated filesystems.  To allow the FS to
+ * choose to pay the cost of 3) only once we call batch_write, if the
+ * FS supports it.
+ */


Thanks Pekka!
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