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SubjectRe: [PATCH] mm, soft-offline: convert parameter to pfn
Date
On Wed, Oct 16, 2019 at 10:34:52AM +0200, David Hildenbrand wrote:
> On 16.10.19 10:27, Naoya Horiguchi wrote:
> > On Wed, Oct 16, 2019 at 09:56:19AM +0200, David Hildenbrand wrote:
> > > On 16.10.19 09:09, Naoya Horiguchi wrote:
> > > > Hi,
> > > >
> > > > I wrote a simple cleanup for parameter of soft_offline_page(),
> > > > based on thread https://lkml.org/lkml/2019/10/11/57.
> > > >
> > > > I know that we need more cleanup on hwpoison-inject, but I think
> > > > that will be mentioned in re-write patchset Oscar is preparing now.
> > > > So let me shared only this part as a separate one now.
> > ...
> > >
> > > I think you should rebase that patch on linux-next (where the
> > > pfn_to_online_page() check is in place). I assume you'll want to move the
> > > pfn_to_online_page() check into soft_offline_page() then as well?
> >
> > I rebased to next-20191016. And yes, we will move pfn_to_online_page()
> > into soft offline code. It seems that we can also move pfn_valid(),
> > but is simply moving like below good enough for you?
>
> At least I can't am the patch to current next/master (due to
> pfn_to_online_page()).
>
> >
> > @@ -1877,11 +1877,17 @@ static int soft_offline_free_page(struct page *page)
> > * This is not a 100% solution for all memory, but tries to be
> > * ``good enough'' for the majority of memory.
> > */
> > -int soft_offline_page(struct page *page, int flags)
> > +int soft_offline_page(unsigned long pfn, int flags)
> > {
> > int ret;
> > - unsigned long pfn = page_to_pfn(page);
> > + struct page *page;
> > + if (!pfn_valid(pfn))
> > + return -ENXIO;
> > + /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
> > + if (!pfn_to_online_page(pfn))
> > + return -EIO;
> > + page = pfn_to_page(pfn);
> > if (is_zone_device_page(page)) {
> > pr_debug_ratelimited("soft_offline: %#lx page is device page\n",
> > pfn);
> > --
> >
> > Or we might have an option to do as memory_failure() does like below:
>
> In contrast to soft offlining, memory failure can deal with devmem. So I
> think the above makes sense.

OK, so here's the revised one.

Thanks,
Naoya Horiguchi
---
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date: Wed, 16 Oct 2019 17:00:33 +0900
Subject: [PATCH] mm, soft-offline: convert parameter to pfn

Currently soft_offline_page() receives struct page, and its sibling
memory_failure() receives pfn. This discrepancy looks weird and makes
precheck on pfn validity tricky. So let's align them.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
drivers/base/memory.c | 7 +------
include/linux/mm.h | 2 +-
mm/madvise.c | 2 +-
mm/memory-failure.c | 14 ++++++++++----
4 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 55907c27075b..a757d9ed88a7 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -538,12 +538,7 @@ static ssize_t soft_offline_page_store(struct device *dev,
if (kstrtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
- if (!pfn_valid(pfn))
- return -ENXIO;
- /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
- if (!pfn_to_online_page(pfn))
- return -EIO;
- ret = soft_offline_page(pfn_to_page(pfn), 0);
+ ret = soft_offline_page(pfn, 0);
return ret == 0 ? count : ret;
}

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 44d058723db9..fd360d208346 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2794,7 +2794,7 @@ extern int sysctl_memory_failure_early_kill;
extern int sysctl_memory_failure_recovery;
extern void shake_page(struct page *p, int access);
extern atomic_long_t num_poisoned_pages __read_mostly;
-extern int soft_offline_page(struct page *page, int flags);
+extern int soft_offline_page(unsigned long pfn, int flags);


/*
diff --git a/mm/madvise.c b/mm/madvise.c
index 2be9f3fdb05e..99dd06fecfa9 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -887,7 +887,7 @@ static int madvise_inject_error(int behavior,
pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
pfn, start);

- ret = soft_offline_page(page, MF_COUNT_INCREASED);
+ ret = soft_offline_page(pfn, MF_COUNT_INCREASED);
if (ret)
return ret;
continue;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 05c8c6df25e6..bdf408d7f65c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1476,7 +1476,7 @@ static void memory_failure_work_func(struct work_struct *work)
if (!gotten)
break;
if (entry.flags & MF_SOFT_OFFLINE)
- soft_offline_page(pfn_to_page(entry.pfn), entry.flags);
+ soft_offline_page(entry.pfn, entry.flags);
else
memory_failure(entry.pfn, entry.flags);
}
@@ -1857,7 +1857,7 @@ static int soft_offline_free_page(struct page *page)

/**
* soft_offline_page - Soft offline a page.
- * @page: page to offline
+ * @pfn: pfn to soft-offline
* @flags: flags. Same as memory_failure().
*
* Returns 0 on success, otherwise negated errno.
@@ -1877,11 +1877,17 @@ static int soft_offline_free_page(struct page *page)
* This is not a 100% solution for all memory, but tries to be
* ``good enough'' for the majority of memory.
*/
-int soft_offline_page(struct page *page, int flags)
+int soft_offline_page(unsigned long pfn, int flags)
{
int ret;
- unsigned long pfn = page_to_pfn(page);
+ struct page *page;

+ if (!pfn_valid(pfn))
+ return -ENXIO;
+ /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
+ page = pfn_to_online_page(pfn);
+ if (!page)
+ return -EIO;
if (is_zone_device_page(page)) {
pr_debug_ratelimited("soft_offline: %#lx page is device page\n",
pfn);
--
2.17.1
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