| Message ID | 20121016130927.GA5603@barrios (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Tue, Oct 16, 2012 at 9:09 PM, Minchan Kim <minchan@kernel.org> wrote: > > Good point. You can check it in __zone_reclaim and change gfp_mask of scan_control > because it's never hot path. > >> >> So could you make sure it is safe to move the branch into >> __alloc_pages_slowpath()? If so, I will add the check into >> gfp_to_alloc_flags(). > > How about this? It is quite smart change, :-) Considered that other part(sched.h) of the patch need update, I will merge your change into -v1 for further review with your Signed-off-by if you have no objection. > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index d976957..b3607fa 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2614,10 +2614,16 @@ retry_cpuset: > page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order, > zonelist, high_zoneidx, alloc_flags, > preferred_zone, migratetype); > - if (unlikely(!page)) > + if (unlikely(!page)) { > + /* > + * Resume path can deadlock because block device > + * isn't active yet. > + */ Not only resume path, I/O transfer or its error handling path may deadlock too. > + if (unlikely(tsk_memalloc_no_io(current))) > + gfp_mask &= ~GFP_IOFS; > page = __alloc_pages_slowpath(gfp_mask, order, > zonelist, high_zoneidx, nodemask, > preferred_zone, migratetype); > + } > > trace_mm_page_alloc(page, order, gfp_mask, migratetype); > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index b5e45f4..6c2ccdd 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -3290,6 +3290,16 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) > }; > unsigned long nr_slab_pages0, nr_slab_pages1; > > + if (unlikely(tsk_memalloc_no_io(current))) { > + sc.gfp_mask &= ~GFP_IOFS; > + shrink.gfp_mask = sc.gfp_mask; > + /* > + * We allow to reclaim only clean pages. > + * It can affect RECLAIM_SWAP and RECLAIM_WRITE mode > + * but this is really rare event and allocator can > * fallback to other zones. > + */ > + sc.may_writepage = 0; > + sc.may_swap = 0; > + } > + > cond_resched(); > /* > * We need to be able to allocate from the reserves for RECLAIM_SWAP > Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Oct 16, 2012 at 09:47:03PM +0800, Ming Lei wrote: > On Tue, Oct 16, 2012 at 9:09 PM, Minchan Kim <minchan@kernel.org> wrote: > > > > Good point. You can check it in __zone_reclaim and change gfp_mask of scan_control > > because it's never hot path. > > > >> > >> So could you make sure it is safe to move the branch into > >> __alloc_pages_slowpath()? If so, I will add the check into > >> gfp_to_alloc_flags(). > > > > How about this? > > It is quite smart change, :-) > > Considered that other part(sched.h) of the patch need update, I > will merge your change into -v1 for further review with your > Signed-off-by if you have no objection. No problem. :)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d976957..b3607fa 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2614,10 +2614,16 @@ retry_cpuset: page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order, zonelist, high_zoneidx, alloc_flags, preferred_zone, migratetype); - if (unlikely(!page)) + if (unlikely(!page)) { + /* + * Resume path can deadlock because block device + * isn't active yet. + */ + if (unlikely(tsk_memalloc_no_io(current))) + gfp_mask &= ~GFP_IOFS; page = __alloc_pages_slowpath(gfp_mask, order, zonelist, high_zoneidx, nodemask, preferred_zone, migratetype); + } trace_mm_page_alloc(page, order, gfp_mask, migratetype); diff --git a/mm/vmscan.c b/mm/vmscan.c index b5e45f4..6c2ccdd 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3290,6 +3290,16 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) }; unsigned long nr_slab_pages0, nr_slab_pages1; + if (unlikely(tsk_memalloc_no_io(current))) { + sc.gfp_mask &= ~GFP_IOFS; + shrink.gfp_mask = sc.gfp_mask; + /* + * We allow to reclaim only clean pages. + * It can affect RECLAIM_SWAP and RECLAIM_WRITE mode + * but this is really rare event and allocator can * fallback to other zones. + */ + sc.may_writepage = 0; + sc.may_swap = 0; + } + cond_resched(); /*