Re: checkpointer continuous flushing

Le 07/06/2015 16:53, Fabien COELHO a écrit :
> +» » /*·Others:·say·that·data·should·not·be·kept·in·memory...
> +» » ·*·This·is·not·exactly·what·we·want·to·say,·because·we·want·to·write
> +» » ·*·the·data·for·durability·but·we·may·need·it·later·nevertheless.
> +» » ·*·It·seems·that·Linux·would·free·the·memory·*if*·the·data·has
> +» » ·*·already·been·written·do·disk,·else·it·is·ignored.
> +» » ·*·For·FreeBSD·this·may·have·the·desired·effect·of·moving·the
> +» » ·*·data·to·the·io·layer.
> +» » ·*/
> +» » rc·=·posix_fadvise(context->fd,·context->offset,·context->nbytes,
> +» » » » » » ···POSIX_FADV_DONTNEED);
> +

It looks a bit hazardous, do you have a benchmark for freeBSD ?

Sources says:case POSIX_FADV_DONTNEED:    /*     * Flush any open FS buffers and then remove pages     * from the
backingVM object.  Using vinvalbuf() here     * is a bit heavy-handed as it flushes all buffers for     * the given
vnode,not just the buffers covering the     * requested range.
 

-- 
Cédric Villemain +33 (0)6 20 30 22 52
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