Re: [PATCH] mm, soft-offline: convert parameter to pfn
From: David Hildenbrand
Date: Thu Oct 17 2019 - 04:03:01 EST
On 17.10.19 09:50, Naoya Horiguchi wrote:
On Thu, Oct 17, 2019 at 09:16:42AM +0200, David Hildenbrand wrote:
On 17.10.19 01:47, Naoya Horiguchi wrote:
On Wed, Oct 16, 2019 at 10:57:57AM +0200, David Hildenbrand wrote:
On 16.10.19 10:54, Naoya Horiguchi wrote:
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()).
Could also be that my "git am" skills failed as the mail was not a
proper patch itself :)
Sorry for the inconvenience, my company email system breaks original
message by introducing quoted-printable format ('=20' or '=3D').
Most mail client usually handles it but git-am doesn't.
I give up using it and send via smtp.gmail.com.
@@ -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)) {
-> this is now no longer possible! So you can drop the whole if
(is_zone_device....) case
OK, thanks. I updated it.
Thanks,
Naoya Horiguchi
---
From 5faf227839b578726fe7f5ff414a153abb3b3a31 Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Date: Thu, 17 Oct 2019 08:40:53 +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@xxxxxxxxxxxxx>
---
drivers/base/memory.c | 7 +------
include/linux/mm.h | 2 +-
mm/madvise.c | 2 +-
mm/memory-failure.c | 19 +++++++++----------
4 files changed, 12 insertions(+), 18 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..af2712004a4d 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.
@@ -1877,18 +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 (is_zone_device_page(page)) {
- pr_debug_ratelimited("soft_offline: %#lx page is device page\n",
- pfn);
- if (flags & MF_COUNT_INCREASED)
- put_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)
If you pass in a PFN with MF_COUNT_INCREASED via mm/madvise.c, you would now
no longer do a put_page(page) in case of ZONE_DEVICE (!page =
pfn_to_online_page(pfn);)
Yes, right.
something like this
page = pfn_to_online_page(pfn);
if (!page) {
/*
* With MF_COUNT_INCREASED, we can use pfn_to_page() directly
* (esp., ZONE_DEVICE).
*/
if (flags & MF_COUNT_INCREASED)
put_page(pfn_to_page(page));
return -EIO;
}
For !pfn_valid(pfn), this is not relevant.
Actually I guess that !pfn_valid() never happens when called from
madvise_inject_error(), because madvise_inject_error() gets pfn via
get_user_pages_fast() which only returns valid page for valid pfn.
And we plan to remove MF_COUNT_INCREASED by Oscar's re-design work,
so I start feeling that this patch should come on top of his tree.
I agree, let's clean that up first.
--
Thanks,
David / dhildenb