On Tue, Nov 24, 2015 at 01:36:14PM +0100, Vlastimil Babka wrote: > The information in /sys/kernel/debug/page_owner includes the migratetype of > the pageblock the page belongs to. This is also checked against the page's > migratetype (as declared by gfp_flags during its allocation), and the page is > reported as Fallback if its migratetype differs from the pageblock's one. > > This is somewhat misleading because in fact fallback allocation is not the > only > reason why these two can differ. It also doesn't direcly provide the page's > migratetype, although it's possible to derive that from the gfp_flags. > > It's arguably better to print both page and pageblock's migratetype and leave > the interpretation to the consumer than to suggest fallback allocation as the > only possible reason. While at it, we can print the migratetypes as string > the same way as /proc/pagetypeinfo does, as some of the numeric values depend > on kernel configuration. For that, this patch moves the migratetype_names > array from #ifdef CONFIG_PROC_FS part of mm/vmstat.c to mm/page_alloc.c and > exports it. > > Example page_owner entry after the patch: > > Page allocated via order 0, mask 0x2420848 > PFN 512 type Reclaimable Block 1 type Reclaimable Flags R LA > [<ffffffff81164e8a>] __alloc_pages_nodemask+0x15a/0xa30 > [<ffffffff811ab808>] alloc_pages_current+0x88/0x120 > [<ffffffff8115bc36>] __page_cache_alloc+0xe6/0x120 > [<ffffffff8115c226>] pagecache_get_page+0x56/0x200 > [<ffffffff81205892>] __getblk_slow+0xd2/0x2b0 > [<ffffffff81205ab0>] __getblk_gfp+0x40/0x50 > [<ffffffff81206ad7>] __breadahead+0x17/0x50 > [<ffffffffa0437b27>] __ext4_get_inode_loc+0x397/0x3e0 [ext4] > > Signed-off-by: Vlastimil Babka <[email protected]> > --- > include/linux/mmzone.h | 3 +++ > mm/page_alloc.c | 13 +++++++++++++ > mm/page_owner.c | 6 +++--- > mm/vmstat.c | 13 ------------- > 4 files changed, 19 insertions(+), 16 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 3b6fb71..2bfad18 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -63,6 +63,9 @@ enum { > MIGRATE_TYPES > }; > > +/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */ > +extern char * const migratetype_names[MIGRATE_TYPES]; > + > #ifdef CONFIG_CMA > # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA) > #else > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 35ab351..61a023a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -229,6 +229,19 @@ static char * const zone_names[MAX_NR_ZONES] = { > #endif > }; > > +char * const migratetype_names[MIGRATE_TYPES] = { > + "Unmovable", > + "Movable", > + "Reclaimable", > + "HighAtomic", > +#ifdef CONFIG_CMA > + "CMA", > +#endif > +#ifdef CONFIG_MEMORY_ISOLATION > + "Isolate", > +#endif > +}; > + > compound_page_dtor * const compound_page_dtors[] = { > NULL, > free_compound_page, > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 983c3a1..f35826e 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -110,11 +110,11 @@ print_page_owner(char __user *buf, size_t count, > unsigned long pfn, > pageblock_mt = get_pfnblock_migratetype(page, pfn); > page_mt = gfpflags_to_migratetype(page_ext->gfp_mask); > ret += snprintf(kbuf + ret, count - ret, > - "PFN %lu Block %lu type %d %s Flags > %s%s%s%s%s%s%s%s%s%s%s%s\n", > + "PFN %lu type %s Block %lu type %s Flags > %s%s%s%s%s%s%s%s%s%s%s%s\n",
How about generalizing dump_flag_names() more and using it here? This output is neat than dump_flag_names() but not complete. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
