* Re: [PATCH] mm,hwpoison: Return -EBUSY when migration fails
[not found] <20201209092818.30417-1-osalvador@suse.de>
@ 2020-12-09 10:25 ` Vlastimil Babka
2020-12-09 10:38 ` Oscar Salvador
0 siblings, 1 reply; 2+ messages in thread
From: Vlastimil Babka @ 2020-12-09 10:25 UTC (permalink / raw)
To: Oscar Salvador, akpm; +Cc: n-horiguchi, linux-mm, linux-kernel, Linux API
On 12/9/20 10:28 AM, Oscar Salvador wrote:
> Currently, we return -EIO when we fail to migrate the page.
>
> Migrations' failures are rather transient as they can happen due to
> several reasons, e.g: high page refcount bump, mapping->migrate_page
> failing etc.
> All meaning that at that time the page could not be migrated, but
> that has nothing to do with an EIO error.
>
> Let us return -EBUSY instead, as we do in case we failed to isolate
> the page.
>
> While are it, let us remove the "ret" print as its value does not change.
>
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Technically this affects madvise(2) so let's cc linux-api. The manpage doesn't
document error codes of MADV_HWPOISON and MADV_SOFT_OFFLINE (besides EPERM)
though so nothing to adjust there. It's meant only for the hwpoison testing
suite anyway.
> ---
> mm/memory-failure.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 428991e297e2..1942fb83ac64 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1849,11 +1849,11 @@ static int __soft_offline_page(struct page *page)
> pr_info("soft offline: %#lx: %s migration failed %d, type %lx (%pGp)\n",
> pfn, msg_page[huge], ret, page->flags, &page->flags);
> if (ret > 0)
> - ret = -EIO;
> + ret = -EBUSY;
> }
> } else {
> - pr_info("soft offline: %#lx: %s isolation failed: %d, page count %d, type %lx (%pGp)\n",
> - pfn, msg_page[huge], ret, page_count(page), page->flags, &page->flags);
> + pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %lx (%pGp)\n",
> + pfn, msg_page[huge], page_count(page), page->flags, &page->flags);
> ret = -EBUSY;
> }
> return ret;
>
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] mm,hwpoison: Return -EBUSY when migration fails
2020-12-09 10:25 ` [PATCH] mm,hwpoison: Return -EBUSY when migration fails Vlastimil Babka
@ 2020-12-09 10:38 ` Oscar Salvador
0 siblings, 0 replies; 2+ messages in thread
From: Oscar Salvador @ 2020-12-09 10:38 UTC (permalink / raw)
To: Vlastimil Babka; +Cc: akpm, n-horiguchi, linux-mm, linux-kernel, Linux API
On Wed, Dec 09, 2020 at 11:25:31AM +0100, Vlastimil Babka wrote:
> On 12/9/20 10:28 AM, Oscar Salvador wrote:
> > Currently, we return -EIO when we fail to migrate the page.
> >
> > Migrations' failures are rather transient as they can happen due to
> > several reasons, e.g: high page refcount bump, mapping->migrate_page
> > failing etc.
> > All meaning that at that time the page could not be migrated, but
> > that has nothing to do with an EIO error.
> >
> > Let us return -EBUSY instead, as we do in case we failed to isolate
> > the page.
> >
> > While are it, let us remove the "ret" print as its value does not change.
> >
> > Signed-off-by: Oscar Salvador <osalvador@suse.de>
>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
> Technically this affects madvise(2) so let's cc linux-api. The manpage doesn't
> document error codes of MADV_HWPOISON and MADV_SOFT_OFFLINE (besides EPERM)
> though so nothing to adjust there. It's meant only for the hwpoison testing
> suite anyway.
Well, not only for hwpoison testing suite.
RAS/CEC and GHES also use soft_offline_page by means of memory_failure_queue
in case a page cec count goes beyond a certain thereshold, but they do not
really check the return code.
Only madvise does.
--
Oscar Salvador
SUSE L3
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-12-09 10:25 ` [PATCH] mm,hwpoison: Return -EBUSY when migration fails Vlastimil Babka
2020-12-09 10:38 ` Oscar Salvador
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