Re: [PATCH v3 04/28] mm: allow VM_FAULT_RETRY for multiple times

From: Peter Xu
Date: Fri Apr 19 2019 - 15:00:55 EST


On Thu, Apr 18, 2019 at 04:11:08PM -0400, Jerome Glisse wrote:

[...]

> Reviewed-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
>
> A minor comment suggestion below but it can be fix in a followup patch.

[...]

> > +/*
> > + * Returns true if the page fault allows retry and this is the first
> > + * attempt of the fault handling; false otherwise. This is mostly
> > + * used for places where we want to try to avoid taking the mmap_sem
> > + * for too long a time when waiting for another condition to change,
> > + * in which case we can try to be polite to release the mmap_sem in
> > + * the first round to avoid potential starvation of other processes
> > + * that would also want the mmap_sem.
> > + */
>
> You should be using kernel function documentation style above.

I'm switching to this:

/**
* fault_flag_allow_retry_first - check ALLOW_RETRY the first time
*
* This is mostly used for places where we want to try to avoid taking
* the mmap_sem for too long a time when waiting for another condition
* to change, in which case we can try to be polite to release the
* mmap_sem in the first round to avoid potential starvation of other
* processes that would also want the mmap_sem.
*
* Return: true if the page fault allows retry and this is the first
* attempt of the fault handling; false otherwise.
*/

I'm still keeping the r-b, assuming that's ok.

Thanks!

--
Peter Xu