| Message ID | 20181114235040.36180-1-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: use managed_zone() for more exact check in zone iteration | expand |
On Thu, 15 Nov 2018 07:50:40 +0800 Wei Yang <richard.weiyang@gmail.com> wrote: > For one zone, there are three digits to describe its space range: > > spanned_pages > present_pages > managed_pages > > The detailed meaning is written in include/linux/mmzone.h. This patch > concerns about the last two. > > present_pages is physical pages existing within the zone > managed_pages is present pages managed by the buddy system > > >From the definition, managed_pages is a more strict condition than > present_pages. > > There are two functions using zone's present_pages as a boundary: > > populated_zone() > for_each_populated_zone() > > By going through the kernel tree, most of their users are willing to > access pages managed by the buddy system, which means it is more exact > to check zone's managed_pages for a validation. > > This patch replaces those checks on present_pages to managed_pages by: > > * change for_each_populated_zone() to for_each_managed_zone() > * convert for_each_populated_zone() to for_each_zone() and check > populated_zone() where is necessary > * change populated_zone() to managed_zone() at proper places > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> > > --- > > Michal, after last mail, I did one more thing to replace > populated_zone() with managed_zone() at proper places. > > One thing I am not sure is those places in mm/compaction.c. I have > chaged them. If not, please let me know. > > BTW, I did a boot up test with the patched kernel and looks smooth. Seems sensible, but a bit scary. A basic boot test is unlikely to expose subtle gremlins. Worse, the situations in which managed_zone() != populated_zone() are rare(?), so it will take a long time for problems to be discovered, I expect. I'll toss it in there for now, let's see who breaks :(
On Thu, Nov 15, 2018 at 01:37:35PM -0800, Andrew Morton wrote: >On Thu, 15 Nov 2018 07:50:40 +0800 Wei Yang <richard.weiyang@gmail.com> wrote: > >> For one zone, there are three digits to describe its space range: >> >> spanned_pages >> present_pages >> managed_pages >> >> The detailed meaning is written in include/linux/mmzone.h. This patch >> concerns about the last two. >> >> present_pages is physical pages existing within the zone >> managed_pages is present pages managed by the buddy system >> >> >From the definition, managed_pages is a more strict condition than >> present_pages. >> >> There are two functions using zone's present_pages as a boundary: >> >> populated_zone() >> for_each_populated_zone() >> >> By going through the kernel tree, most of their users are willing to >> access pages managed by the buddy system, which means it is more exact >> to check zone's managed_pages for a validation. >> >> This patch replaces those checks on present_pages to managed_pages by: >> >> * change for_each_populated_zone() to for_each_managed_zone() >> * convert for_each_populated_zone() to for_each_zone() and check >> populated_zone() where is necessary >> * change populated_zone() to managed_zone() at proper places >> >> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> >> >> --- >> >> Michal, after last mail, I did one more thing to replace >> populated_zone() with managed_zone() at proper places. >> >> One thing I am not sure is those places in mm/compaction.c. I have >> chaged them. If not, please let me know. >> >> BTW, I did a boot up test with the patched kernel and looks smooth. > >Seems sensible, but a bit scary. A basic boot test is unlikely to >expose subtle gremlins. > Agree. >Worse, the situations in which managed_zone() != populated_zone() are >rare(?), so it will take a long time for problems to be discovered, I >expect. Hmm... I created a virtual machine with 4 nodes, which has total 6 populated zones. All of them are different. This is a little bit out of my expactation. > >I'll toss it in there for now, let's see who breaks :( Thanks.
On Thu 15-11-18 13:37:35, Andrew Morton wrote: [...] > Worse, the situations in which managed_zone() != populated_zone() are > rare(?), so it will take a long time for problems to be discovered, I > expect. We would basically have to deplete the whole zone by the bootmem allocator or pull out all pages from the page allocator. E.g. memory hotplug decreases both managed and present counters. I am actually not sure that is 100% correct (put on my TODO list to check). There is no consistency in that regards. That being said, I will review the patch (today hopefully) but fundamentally most users should indeed care about managed pages when iterating zones with memory. There should be a good reason why they might want to look at reserved pages.
On Thu 15-11-18 07:50:40, Wei Yang wrote: [...] > @@ -1193,8 +1196,8 @@ static unsigned int count_free_highmem_pages(void) > struct zone *zone; > unsigned int cnt = 0; > > - for_each_populated_zone(zone) > - if (is_highmem(zone)) > + for_each_zone(zone) > + if (populated_zone(zone) && is_highmem(zone)) > cnt += zone_page_state(zone, NR_FREE_PAGES); this should be for_each_managed_zone because we only care about highmem zones which have pages in the allocator (NR_FREE_PAGES). > > return cnt; > @@ -1239,10 +1242,10 @@ static unsigned int count_highmem_pages(void) > struct zone *zone; > unsigned int n = 0; > > - for_each_populated_zone(zone) { > + for_each_zone(zone) { > unsigned long pfn, max_zone_pfn; > > - if (!is_highmem(zone)) > + if (!populated_zone(zone) || !is_highmem(zone)) > continue; > > mark_free_pages(zone); I am not familiar with this code much but I strongly suspect that we do want for_each_managed_zone here because saveable_highmem_page skips over all reserved pages which rules out the bootmem. But this should be double checked with Rafael (Cc-ed). Rafael, does this loop care about pages which are not managed by the page allocator? > @@ -1305,8 +1308,8 @@ static unsigned int count_data_pages(void) > unsigned long pfn, max_zone_pfn; > unsigned int n = 0; > > - for_each_populated_zone(zone) { > - if (is_highmem(zone)) > + for_each_zone(zone) { > + if (!populated_zone(zone) || is_highmem(zone)) > continue; > > mark_free_pages(zone); > @@ -1399,9 +1402,12 @@ static void copy_data_pages(struct memory_bitmap *copy_bm, > struct zone *zone; > unsigned long pfn; > > - for_each_populated_zone(zone) { > + for_each_zone(zone) { > unsigned long max_zone_pfn; > > + if (!populated_zone(zone)) > + continue; > + > mark_free_pages(zone); > max_zone_pfn = zone_end_pfn(zone); > for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) > @@ -1717,7 +1723,10 @@ int hibernate_preallocate_memory(void) > saveable += save_highmem; > highmem = save_highmem; > size = 0; > - for_each_populated_zone(zone) { > + for_each_zone(zone) { > + if (!populated_zone(zone)) > + continue; > + > size += snapshot_additional_pages(zone); > if (is_highmem(zone)) > highmem += zone_page_state(zone, NR_FREE_PAGES); ditto for the above. > @@ -1863,8 +1872,8 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) > struct zone *zone; > unsigned int free = alloc_normal; > > - for_each_populated_zone(zone) > - if (!is_highmem(zone)) > + for_each_zone(zone) > + if (populated_zone(zone) && !is_highmem(zone)) > free += zone_page_state(zone, NR_FREE_PAGES); > > nr_pages += count_pages_for_highmem(nr_highmem); This one should be for_each_managed_zone (NR_FREE_PAGES) The rest looks good to me.
On Fri, 2018-11-16 at 10:57 +0100, Michal Hocko wrote: > On Thu 15-11-18 13:37:35, Andrew Morton wrote: > [...] > > Worse, the situations in which managed_zone() != populated_zone() > > are > > rare(?), so it will take a long time for problems to be discovered, > > I > > expect. > > We would basically have to deplete the whole zone by the bootmem > allocator or pull out all pages from the page allocator. E.g. memory > hotplug decreases both managed and present counters. I am actually > not > sure that is 100% correct (put on my TODO list to check). There is no > consistency in that regards. We can only offline non-reserved pages (so, managed pages). Since present pages holds reserved_pages + managed_pages, decreasing both should be fine unless I am mistaken. Oscar Salvador
On Fri 16-11-18 12:05:04, osalvador wrote: > On Fri, 2018-11-16 at 10:57 +0100, Michal Hocko wrote: [...] > > E.g. memory hotplug decreases both managed and present counters. I > > am actually not sure that is 100% correct (put on my TODO list to > > check). There is no consistency in that regards. > > We can only offline non-reserved pages (so, managed pages). Yes > Since present pages holds reserved_pages + managed_pages, decreasing > both should be fine unless I am mistaken. Well, present_pages is defined as "physical pages existing within the zone" and those pages are still existing but they are offline. But as I've said I have to think about it some more
On Fri, Nov 16, 2018 at 12:26:03PM +0100, Michal Hocko wrote: >On Fri 16-11-18 12:05:04, osalvador wrote: >> On Fri, 2018-11-16 at 10:57 +0100, Michal Hocko wrote: >[...] >> > E.g. memory hotplug decreases both managed and present counters. I >> > am actually not sure that is 100% correct (put on my TODO list to >> > check). There is no consistency in that regards. >> >> We can only offline non-reserved pages (so, managed pages). > >Yes > >> Since present pages holds reserved_pages + managed_pages, decreasing >> both should be fine unless I am mistaken. > >Well, present_pages is defined as "physical pages existing within the zone" >and those pages are still existing but they are offline. But as I've >said I have to think about it some more I may not catch up with your discussions, while I'd like to share what I learnt. online_pages() online_pages_range() zone->present_pages += onlined_pages; __offline_pages() adjust_managed_page_count() zone->present_pages -= offlined_pages; The two counters: present_pages & managed_pages would be adjusted during online/offline. While I am not sure when *reserved_pages* would be adjusted. Will we add this hot-added memory into memblock.reserved? and allocate memory by memblock_alloc() after system bootup? >-- >Michal Hocko >SUSE Labs
On Fri 16-11-18 15:58:28, Wei Yang wrote: > On Fri, Nov 16, 2018 at 12:26:03PM +0100, Michal Hocko wrote: > >On Fri 16-11-18 12:05:04, osalvador wrote: > >> On Fri, 2018-11-16 at 10:57 +0100, Michal Hocko wrote: > >[...] > >> > E.g. memory hotplug decreases both managed and present counters. I > >> > am actually not sure that is 100% correct (put on my TODO list to > >> > check). There is no consistency in that regards. > >> > >> We can only offline non-reserved pages (so, managed pages). > > > >Yes > > > >> Since present pages holds reserved_pages + managed_pages, decreasing > >> both should be fine unless I am mistaken. > > > >Well, present_pages is defined as "physical pages existing within the zone" > >and those pages are still existing but they are offline. But as I've > >said I have to think about it some more > > I may not catch up with your discussions, while I'd like to share what I > learnt. > > online_pages() > online_pages_range() > zone->present_pages += onlined_pages; > > __offline_pages() > adjust_managed_page_count() > zone->present_pages -= offlined_pages; > > The two counters: present_pages & managed_pages would be adjusted during > online/offline. > > While I am not sure when *reserved_pages* would be adjusted. Will we add > this hot-added memory into memblock.reserved? and allocate memory by > memblock_alloc() after system bootup? This is not really related to this patch. I have only mentioned the memory hotplug as an example. I would rather focus on the change itself so let's not get too off topic here.
On Fri, Nov 16, 2018 at 11:24:05AM +0100, Michal Hocko wrote: >On Thu 15-11-18 07:50:40, Wei Yang wrote: >[...] >> @@ -1193,8 +1196,8 @@ static unsigned int count_free_highmem_pages(void) >> struct zone *zone; >> unsigned int cnt = 0; >> >> - for_each_populated_zone(zone) >> - if (is_highmem(zone)) >> + for_each_zone(zone) >> + if (populated_zone(zone) && is_highmem(zone)) >> cnt += zone_page_state(zone, NR_FREE_PAGES); > >this should be for_each_managed_zone because we only care about highmem >zones which have pages in the allocator (NR_FREE_PAGES). > >> >> return cnt; >> @@ -1239,10 +1242,10 @@ static unsigned int count_highmem_pages(void) >> struct zone *zone; >> unsigned int n = 0; >> >> - for_each_populated_zone(zone) { >> + for_each_zone(zone) { >> unsigned long pfn, max_zone_pfn; >> >> - if (!is_highmem(zone)) >> + if (!populated_zone(zone) || !is_highmem(zone)) >> continue; >> >> mark_free_pages(zone); > >I am not familiar with this code much but I strongly suspect that we do >want for_each_managed_zone here because saveable_highmem_page skips over >all reserved pages which rules out the bootmem. But this should be >double checked with Rafael (Cc-ed). > >Rafael, does this loop care about pages which are not managed by the >page allocator? > Hi, Rafael Your opinion on this change and the following one is appreciated :-) >> @@ -1305,8 +1308,8 @@ static unsigned int count_data_pages(void) >> unsigned long pfn, max_zone_pfn; >> unsigned int n = 0; >> >> - for_each_populated_zone(zone) { >> - if (is_highmem(zone)) >> + for_each_zone(zone) { >> + if (!populated_zone(zone) || is_highmem(zone)) >> continue; >> >> mark_free_pages(zone); >> @@ -1399,9 +1402,12 @@ static void copy_data_pages(struct memory_bitmap *copy_bm, >> struct zone *zone; >> unsigned long pfn; >> >> - for_each_populated_zone(zone) { >> + for_each_zone(zone) { >> unsigned long max_zone_pfn; >> >> + if (!populated_zone(zone)) >> + continue; >> + >> mark_free_pages(zone); >> max_zone_pfn = zone_end_pfn(zone); >> for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) >> @@ -1717,7 +1723,10 @@ int hibernate_preallocate_memory(void) >> saveable += save_highmem; >> highmem = save_highmem; >> size = 0; >> - for_each_populated_zone(zone) { >> + for_each_zone(zone) { >> + if (!populated_zone(zone)) >> + continue; >> + >> size += snapshot_additional_pages(zone); >> if (is_highmem(zone)) >> highmem += zone_page_state(zone, NR_FREE_PAGES); > >ditto for the above. > > >> @@ -1863,8 +1872,8 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) >> struct zone *zone; >> unsigned int free = alloc_normal; >> >> - for_each_populated_zone(zone) >> - if (!is_highmem(zone)) >> + for_each_zone(zone) >> + if (populated_zone(zone) && !is_highmem(zone)) >> free += zone_page_state(zone, NR_FREE_PAGES); >> >> nr_pages += count_pages_for_highmem(nr_highmem); > >This one should be for_each_managed_zone (NR_FREE_PAGES) > >The rest looks good to me. >-- >Michal Hocko >SUSE Labs
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index dc3cede7f2ec..015430bf0c63 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -265,7 +265,7 @@ void arch_set_page_states(int make_stable) return; if (make_stable) drain_local_pages(NULL); - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { spin_lock_irqsave(&zone->lock, flags); for_each_migratetype_order(order, t) { list_for_each(l, &zone->free_area[order].free_list[t]) { diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 847705a6d0ec..2174baba0546 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -937,11 +937,9 @@ extern struct zone *next_zone(struct zone *zone); zone; \ zone = next_zone(zone)) -#define for_each_populated_zone(zone) \ - for (zone = (first_online_pgdat())->node_zones; \ - zone; \ - zone = next_zone(zone)) \ - if (!populated_zone(zone)) \ +#define for_each_managed_zone(zone) \ + for_each_zone(zone) \ + if (!managed_zone(zone)) \ ; /* do nothing */ \ else diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index b0308a2c6000..aa99efa73d89 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -592,10 +592,13 @@ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) INIT_LIST_HEAD(list); - for_each_populated_zone(zone) { + for_each_zone(zone) { unsigned long zone_start, zone_end; struct mem_extent *ext, *cur, *aux; + if (!populated_zone(zone)) + continue; + zone_start = zone->zone_start_pfn; zone_end = zone_end_pfn(zone); @@ -1193,8 +1196,8 @@ static unsigned int count_free_highmem_pages(void) struct zone *zone; unsigned int cnt = 0; - for_each_populated_zone(zone) - if (is_highmem(zone)) + for_each_zone(zone) + if (populated_zone(zone) && is_highmem(zone)) cnt += zone_page_state(zone, NR_FREE_PAGES); return cnt; @@ -1239,10 +1242,10 @@ static unsigned int count_highmem_pages(void) struct zone *zone; unsigned int n = 0; - for_each_populated_zone(zone) { + for_each_zone(zone) { unsigned long pfn, max_zone_pfn; - if (!is_highmem(zone)) + if (!populated_zone(zone) || !is_highmem(zone)) continue; mark_free_pages(zone); @@ -1305,8 +1308,8 @@ static unsigned int count_data_pages(void) unsigned long pfn, max_zone_pfn; unsigned int n = 0; - for_each_populated_zone(zone) { - if (is_highmem(zone)) + for_each_zone(zone) { + if (!populated_zone(zone) || is_highmem(zone)) continue; mark_free_pages(zone); @@ -1399,9 +1402,12 @@ static void copy_data_pages(struct memory_bitmap *copy_bm, struct zone *zone; unsigned long pfn; - for_each_populated_zone(zone) { + for_each_zone(zone) { unsigned long max_zone_pfn; + if (!populated_zone(zone)) + continue; + mark_free_pages(zone); max_zone_pfn = zone_end_pfn(zone); for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) @@ -1717,7 +1723,10 @@ int hibernate_preallocate_memory(void) saveable += save_highmem; highmem = save_highmem; size = 0; - for_each_populated_zone(zone) { + for_each_zone(zone) { + if (!populated_zone(zone)) + continue; + size += snapshot_additional_pages(zone); if (is_highmem(zone)) highmem += zone_page_state(zone, NR_FREE_PAGES); @@ -1863,8 +1872,8 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) struct zone *zone; unsigned int free = alloc_normal; - for_each_populated_zone(zone) - if (!is_highmem(zone)) + for_each_zone(zone) + if (populated_zone(zone) && !is_highmem(zone)) free += zone_page_state(zone, NR_FREE_PAGES); nr_pages += count_pages_for_highmem(nr_highmem); diff --git a/mm/compaction.c b/mm/compaction.c index 7c607479de4a..8867c011dd45 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -276,7 +276,7 @@ void reset_isolation_suitable(pg_data_t *pgdat) for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { struct zone *zone = &pgdat->node_zones[zoneid]; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; /* Only flush if a full compaction finished recently */ @@ -1832,7 +1832,7 @@ static void compact_node(int nid) for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { zone = &pgdat->node_zones[zoneid]; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; cc.nr_freepages = 0; @@ -1927,7 +1927,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat) for (zoneid = 0; zoneid <= classzone_idx; zoneid++) { zone = &pgdat->node_zones[zoneid]; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; if (compaction_suitable(zone, pgdat->kcompactd_max_order, 0, @@ -1963,7 +1963,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) int status; zone = &pgdat->node_zones[zoneid]; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; if (compaction_deferred(zone, cc.order)) diff --git a/mm/highmem.c b/mm/highmem.c index 59db3223a5d6..1edc0539d25a 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -111,15 +111,14 @@ EXPORT_SYMBOL(totalhigh_pages); EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx); -unsigned int nr_free_highpages (void) +unsigned int nr_free_highpages(void) { struct zone *zone; unsigned int pages = 0; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) if (is_highmem(zone)) pages += zone_page_state(zone, NR_FREE_PAGES); - } return pages; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4e4ef8fa479d..d0f97b29c96f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2829,7 +2829,7 @@ static int split_huge_pages_set(void *data, u64 val) if (val != 1) return -EINVAL; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { max_zone_pfn = zone_end_pfn(zone); for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { if (!pfn_valid(pfn)) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index c13625c1ad5e..4c3ec240d4d9 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1845,7 +1845,7 @@ static void set_recommended_min_free_kbytes(void) int nr_zones = 0; unsigned long recommended_min; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { /* * We don't need to worry about fragmentation of * ZONE_MOVABLE since it only has movable pages. diff --git a/mm/madvise.c b/mm/madvise.c index 6cb1ca93e290..3a8eced61107 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -677,7 +677,7 @@ static int madvise_inject_error(int behavior, } /* Ensure that all poisoned pages are removed from per-cpu lists */ - for_each_populated_zone(zone) + for_each_managed_zone(zone) drain_all_pages(zone); return 0; diff --git a/mm/migrate.c b/mm/migrate.c index f7e4bfdc13b7..5c4846dd0ae3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1819,7 +1819,7 @@ static bool migrate_balanced_pgdat(struct pglist_data *pgdat, for (z = pgdat->nr_zones - 1; z >= 0; z--) { struct zone *zone = pgdat->node_zones + z; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; /* Avoid waking kswapd by allocating pages_to_migrate pages. */ diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 3f690bae6b78..076f51e86149 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -281,7 +281,7 @@ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat) for (z = 0; z < MAX_NR_ZONES; z++) { struct zone *zone = pgdat->node_zones + z; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; nr_pages += zone_page_state(zone, NR_FREE_PAGES); @@ -316,7 +316,7 @@ static unsigned long highmem_dirtyable_memory(unsigned long total) continue; z = &NODE_DATA(node)->node_zones[i]; - if (!populated_zone(z)) + if (!managed_zone(z)) continue; nr_pages = zone_page_state(z, NR_FREE_PAGES); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c20d3c76bd59..458bd81cf75c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1747,7 +1747,7 @@ void __init page_alloc_init_late(void) memblock_discard(); #endif - for_each_populated_zone(zone) + for_each_managed_zone(zone) set_zone_contiguous(zone); } @@ -2569,9 +2569,8 @@ static void drain_pages(unsigned int cpu) { struct zone *zone; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) drain_pages_zone(cpu, zone); - } } /* @@ -2655,7 +2654,7 @@ void drain_all_pages(struct zone *zone) if (pcp->pcp.count) has_pcps = true; } else { - for_each_populated_zone(z) { + for_each_managed_zone(z) { pcp = per_cpu_ptr(z->pageset, cpu); if (pcp->pcp.count) { has_pcps = true; @@ -4857,7 +4856,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) struct zone *zone; pg_data_t *pgdat; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) continue; @@ -4940,7 +4939,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) "yes" : "no"); } - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { int i; if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) @@ -4999,7 +4998,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) printk(KERN_CONT "\n"); } - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { unsigned int order; unsigned long nr[MAX_ORDER], flags, total = 0; unsigned char types[MAX_ORDER]; @@ -5787,7 +5786,7 @@ void __init setup_per_cpu_pageset(void) struct pglist_data *pgdat; struct zone *zone; - for_each_populated_zone(zone) + for_each_managed_zone(zone) setup_zone_pageset(zone); for_each_online_pgdat(pgdat) @@ -6905,7 +6904,7 @@ static void check_for_memory(pg_data_t *pgdat, int nid) for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) { struct zone *zone = &pgdat->node_zones[zone_type]; - if (populated_zone(zone)) { + if (managed_zone(zone)) { if (IS_ENABLED(CONFIG_HIGHMEM)) node_set_state(nid, N_HIGH_MEMORY); if (zone_type <= ZONE_NORMAL) @@ -7581,7 +7580,7 @@ int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write, if (percpu_pagelist_fraction == old_percpu_pagelist_fraction) goto out; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { unsigned int cpu; for_each_possible_cpu(cpu) diff --git a/mm/vmstat.c b/mm/vmstat.c index 6038ce593ce3..06cd9e9ecba1 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -53,7 +53,7 @@ static void zero_zones_numa_counters(void) { struct zone *zone; - for_each_populated_zone(zone) + for_each_managed_zone(zone) zero_zone_numa_counters(zone); } @@ -256,7 +256,7 @@ void refresh_zone_stat_thresholds(void) } } - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { struct pglist_data *pgdat = zone->zone_pgdat; unsigned long max_drift, tolerate_drift; @@ -753,7 +753,7 @@ static int refresh_cpu_vm_stats(bool do_pagesets) int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, }; int changes = 0; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { struct per_cpu_pageset __percpu *p = zone->pageset; for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) { @@ -854,7 +854,7 @@ void cpu_vm_stats_fold(int cpu) #endif int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, }; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { struct per_cpu_pageset *p; p = per_cpu_ptr(zone->pageset, cpu); @@ -1578,8 +1578,8 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, seq_printf(m, ", %ld", zone->lowmem_reserve[i]); seq_putc(m, ')'); - /* If unpopulated, no other information is useful */ - if (!populated_zone(zone)) { + /* If unmanaged, no other information is useful */ + if (!managed_zone(zone)) { seq_putc(m, '\n'); return; } @@ -1817,7 +1817,7 @@ static bool need_update(int cpu) { struct zone *zone; - for_each_populated_zone(zone) { + for_each_managed_zone(zone) { struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu); BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
For one zone, there are three digits to describe its space range: spanned_pages present_pages managed_pages The detailed meaning is written in include/linux/mmzone.h. This patch concerns about the last two. present_pages is physical pages existing within the zone managed_pages is present pages managed by the buddy system From the definition, managed_pages is a more strict condition than present_pages. There are two functions using zone's present_pages as a boundary: populated_zone() for_each_populated_zone() By going through the kernel tree, most of their users are willing to access pages managed by the buddy system, which means it is more exact to check zone's managed_pages for a validation. This patch replaces those checks on present_pages to managed_pages by: * change for_each_populated_zone() to for_each_managed_zone() * convert for_each_populated_zone() to for_each_zone() and check populated_zone() where is necessary * change populated_zone() to managed_zone() at proper places Signed-off-by: Wei Yang <richard.weiyang@gmail.com> --- Michal, after last mail, I did one more thing to replace populated_zone() with managed_zone() at proper places. One thing I am not sure is those places in mm/compaction.c. I have chaged them. If not, please let me know. BTW, I did a boot up test with the patched kernel and looks smooth. --- arch/s390/mm/page-states.c | 2 +- include/linux/mmzone.h | 8 +++----- kernel/power/snapshot.c | 31 ++++++++++++++++++++----------- mm/compaction.c | 8 ++++---- mm/highmem.c | 5 ++--- mm/huge_memory.c | 2 +- mm/khugepaged.c | 2 +- mm/madvise.c | 2 +- mm/migrate.c | 2 +- mm/page-writeback.c | 4 ++-- mm/page_alloc.c | 19 +++++++++---------- mm/vmstat.c | 14 +++++++------- 12 files changed, 52 insertions(+), 47 deletions(-)