On 04/10/2017 06:02 PM, Michal Hocko wrote: > On Mon 10-04-17 16:27:49, Igor Mammedov wrote: > [...] >> #issue3: >> removable flag flipped to non-removable state >> >> // before series at commit ef0b577b6: >> memory32:offline removable: 0 zones: Normal Movable >> memory33:offline removable: 0 zones: Normal Movable >> memory34:offline removable: 0 zones: Normal Movable >> memory35:offline removable: 0 zones: Normal Movable > > did you mean _after_ the series because the bellow looks like > the original behavior (at least valid_zones). > >> // after series at commit 6a010434 >> memory32:offline removable: 1 zones: Normal >> memory33:offline removable: 1 zones: Normal >> memory34:offline removable: 1 zones: Normal >> memory35:offline removable: 1 zones: Normal Movable >> >> also looking at #issue1 removable flag state doesn't >> seem to be consistent between state changes but maybe that's >> been broken before > > Well, the file has a very questionable semantic. It doesn't provide > a stable information. Anyway put that aside. > is_pageblock_removable_nolock relies on having zone association > which we do not have yet if the memblock is offline. So we need > the following. I will queue this as a preparatory patch. > --- > From 4f3ebc02f4d552d3fe114787ca8a38cc68702208 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <[email protected]> > Date: Mon, 10 Apr 2017 17:59:03 +0200 > Subject: [PATCH] mm, memory_hotplug: consider offline memblocks removable > > is_pageblock_removable_nolock relies on having zone association to > examine all the page blocks to check whether they are movable or free. > This is just wasting of cycles when the memblock is offline. Later patch > in the series will also change the time when the page is associated with > a zone so we let's bail out early if the memblock is offline. > > Reported-by: Igor Mammedov <[email protected]> > Signed-off-by: Michal Hocko <[email protected]>
Acked-by: Vlastimil Babka <[email protected]> > --- > drivers/base/memory.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 9677b6b711b0..0c29ec5598ea 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -128,6 +128,9 @@ static ssize_t show_mem_removable(struct device *dev, > int ret = 1; > struct memory_block *mem = to_memory_block(dev); > > + if (mem->stat != MEM_ONLINE) > + goto out; > + > for (i = 0; i < sections_per_block; i++) { > if (!present_section_nr(mem->start_section_nr + i)) > continue; > @@ -135,6 +138,7 @@ static ssize_t show_mem_removable(struct device *dev, > ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION); > } > > +out: > return sprintf(buf, "%d\n", ret); > } > >
