Messages in this thread | | | Date | Tue, 09 Jun 2015 16:12:32 +0900 | From | Kamezawa Hiroyuki <> | Subject | Re: [RFC PATCH 10/12] mm: add the buddy system interface |
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On 2015/06/04 22:04, Xishi Qiu wrote: > Add the buddy system interface for address range mirroring feature. > Allocate mirrored pages in MIGRATE_MIRROR list. If there is no mirrored pages > left, use other types pages. > > Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> > --- > mm/page_alloc.c | 40 +++++++++++++++++++++++++++++++++++++++- > 1 file changed, 39 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index d4d2066..0fb55288 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -599,6 +599,26 @@ static inline bool is_mirror_pfn(unsigned long pfn) > > return false; > } > + > +static inline bool change_to_mirror(gfp_t gfp_flags, int high_zoneidx) > +{ > + /* > + * Do not alloc mirrored memory below 4G, because 0-4G is > + * all mirrored by default, and the list is always empty. > + */ > + if (high_zoneidx < ZONE_NORMAL) > + return false; > + > + /* Alloc mirrored memory for only kernel */ > + if (gfp_flags & __GFP_MIRROR) > + return true;
GFP_KERNEL itself should imply mirror, I think.
> + > + /* Alloc mirrored memory for both user and kernel */ > + if (sysctl_mirrorable) > + return true;
Reading this, I think this sysctl is not good. The user cannot know what is mirrored because memory may not be mirrored until the sysctl is set.
Thanks, -Kame
> + > + return false; > +} > #endif > > /* > @@ -1796,7 +1816,10 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, > WARN_ON_ONCE(order > 1); > } > spin_lock_irqsave(&zone->lock, flags); > - page = __rmqueue(zone, order, migratetype); > + if (is_migrate_mirror(migratetype)) > + page = __rmqueue_smallest(zone, order, migratetype); > + else > + page = __rmqueue(zone, order, migratetype); > spin_unlock(&zone->lock); > if (!page) > goto failed; > @@ -2928,6 +2951,11 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, > if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE) > alloc_flags |= ALLOC_CMA; > > +#ifdef CONFIG_MEMORY_MIRROR > + if (change_to_mirror(gfp_mask, ac.high_zoneidx)) > + ac.migratetype = MIGRATE_MIRROR; > +#endif > + > retry_cpuset: > cpuset_mems_cookie = read_mems_allowed_begin(); > > @@ -2943,9 +2971,19 @@ retry_cpuset: > > /* First allocation attempt */ > alloc_mask = gfp_mask|__GFP_HARDWALL; > +retry: > page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac); > if (unlikely(!page)) { > /* > + * If there is no mirrored memory, we will alloc other > + * types memory. > + */ > + if (is_migrate_mirror(ac.migratetype)) { > + ac.migratetype = gfpflags_to_migratetype(gfp_mask); > + goto retry; > + } > + > + /* > * Runtime PM, block IO and its error handling path > * can deadlock because I/O on the device might not > * complete. >
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