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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH 10/25] Calculate the alloc_flags for allocation only once
Cc: kosaki.motohiro@jp.fujitsu.com,
       Linux Memory Management List <linux-mm@kvack.org>,
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> > > +	/* 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.