Re: [PATCH 10/25] Calculate the alloc_flags for allocation only once

KOSAKI Motohiro
2009-04-21T10:12:50Z

> > > + /* Avoid recursion of direct reclaim */
> > > + if (p->flags & PF_MEMALLOC)
> > > + goto nopage;
> > > +
> >
> > Again. old code doesn't only check PF_MEMALLOC, but also check TIF_MEMDIE.
> >
>
> But a direct reclaim will have PF_MEMALLOC set and doesn't care about
> the value of TIF_MEMDIE with respect to recursion.
>
> There is still a check made for TIF_MEMDIE for setting ALLOC_NO_WATERMARKS
> in gfp_to_alloc_flags() so that flag is still being taken care of.

Do you mean this is intentional change?
I only said there is changelog-less behavior change.

old code is here.
PF_MEMALLOC and TIF_MEMDIE makes goto nopage. it avoid reclaim.
-------------------------------------------------------------------------
rebalance:
if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
&& !in_interrupt()) {
if (!(gfp_mask & __GFP_NOMEMALLOC)) {
nofail_alloc:
/* go through the zonelist yet again, ignoring mins */
page = get_page_from_freelist(gfp_mask, nodemask, order,
zonelist, high_zoneidx, ALLOC_NO_WATERMARKS);
if (page)
goto got_pg;
if (gfp_mask & __GFP_NOFAIL) {
congestion_wait(WRITE, HZ/50);
goto nofail_alloc;
}
}
goto nopage;
}
-------------------------------------------------------------------------

but I don't oppose this change if it is your intentional.