Re: [PATCH -mmotm 5/5] memcg: dirty pages instrumentation

From: KAMEZAWA Hiroyuki
Date: Sun Mar 14 2010 - 22:34:55 EST


On Mon, 15 Mar 2010 00:26:42 +0100
Andrea Righi <arighi@xxxxxxxxxxx> wrote:

> Apply the cgroup dirty pages accounting and limiting infrastructure to
> the opportune kernel functions.
>
> [ NOTE: for now do not account WritebackTmp pages (FUSE) and NILFS2
> bounce pages. This depends on charging also bounce pages per cgroup. ]
>
> As a bonus, make determine_dirtyable_memory() static again: this
> function isn't used anymore outside page writeback.
>
> Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

A nitpick.

> @@ -660,6 +705,8 @@ void throttle_vm_writeout(gfp_t gfp_mask)
> unsigned long dirty_thresh;
>
> for ( ; ; ) {
> + unsigned long dirty;
> +
> get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
>
> /*
> @@ -668,10 +715,10 @@ void throttle_vm_writeout(gfp_t gfp_mask)
> */
> dirty_thresh += dirty_thresh / 10; /* wheeee... */
>
> - if (global_page_state(NR_UNSTABLE_NFS) +
> - global_page_state(NR_WRITEBACK) <= dirty_thresh)
> - break;
> - congestion_wait(BLK_RW_ASYNC, HZ/10);
> + dirty = get_dirty_writeback_pages();
> + if (dirty <= dirty_thresh)
> + break;
> + congestion_wait(BLK_RW_ASYNC, HZ/10);
>
> /*
> * The caller might hold locks which can prevent IO completion

"dirty" seems not to be necessary.
if (get_dirty_writeback_pages() < dirty_thresh) ?

Thanks,
-Kame



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