memory_failure_dev_pagemap code is a bit complex before introduce RMAP
feature for fsdax. So it is needed to factor some helper functions to
simplify these code.
Signed-off-by: Shiyang Ruan <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Dan Williams <[email protected]>
---
mm/memory-failure.c | 157 ++++++++++++++++++++++++--------------------
1 file changed, 87 insertions(+), 70 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ef402b490663..f1cdd39f01f7 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1499,6 +1499,90 @@ static int try_to_split_thp_page(struct page *page, const char *msg)
return 0;
}
+static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn,
+ struct address_space *mapping, pgoff_t index, int flags)
+{
+ struct to_kill *tk;
+ unsigned long size = 0;
+
+ list_for_each_entry(tk, to_kill, nd)
+ if (tk->size_shift)
+ size = max(size, 1UL << tk->size_shift);
+
+ if (size) {
+ /*
+ * Unmap the largest mapping to avoid breaking up device-dax
+ * mappings which are constant size. The actual size of the
+ * mapping being torn down is communicated in siginfo, see
+ * kill_proc()
+ */
+ loff_t start = (index << PAGE_SHIFT) & ~(size - 1);
+
+ unmap_mapping_range(mapping, start, size, 0);
+ }
+
+ kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags);
+}
+
+static int mf_generic_kill_procs(unsigned long long pfn, int flags,
+ struct dev_pagemap *pgmap)
+{
+ struct page *page = pfn_to_page(pfn);
+ LIST_HEAD(to_kill);
+ dax_entry_t cookie;
+ int rc = 0;
+
+ /*
+ * Pages instantiated by device-dax (not filesystem-dax)
+ * may be compound pages.
+ */
+ page = compound_head(page);
+
+ /*
+ * Prevent the inode from being freed while we are interrogating
+ * the address_space, typically this would be handled by
+ * lock_page(), but dax pages do not use the page lock. This
+ * also prevents changes to the mapping of this pfn until
+ * poison signaling is complete.
+ */
+ cookie = dax_lock_page(page);
+ if (!cookie)
+ return -EBUSY;
+
+ if (hwpoison_filter(page)) {
+ rc = -EOPNOTSUPP;
+ goto unlock;
+ }
+
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ /*
+ * TODO: Handle HMM pages which may need coordination
+ * with device-side memory.
+ */
+ return -EBUSY;
+ }
+
+ /*
+ * Use this flag as an indication that the dax page has been
+ * remapped UC to prevent speculative consumption of poison.
+ */
+ SetPageHWPoison(page);
+
+ /*
+ * Unlike System-RAM there is no possibility to swap in a
+ * different physical page at a given virtual address, so all
+ * userspace consumption of ZONE_DEVICE memory necessitates
+ * SIGBUS (i.e. MF_MUST_KILL)
+ */
+ flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
+ collect_procs(page, &to_kill, true);
+
+ unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
+unlock:
+ dax_unlock_page(page, cookie);
+ return 0;
+}
+
/*
* Called from hugetlb code with hugetlb_lock held.
* If a hugepage is successfully grabbed (so it's determined to handle
@@ -1663,12 +1747,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
struct dev_pagemap *pgmap)
{
struct page *page = pfn_to_page(pfn);
- unsigned long size = 0;
- struct to_kill *tk;
LIST_HEAD(tokill);
- int rc = -EBUSY;
- loff_t start;
- dax_entry_t cookie;
+ int rc = -ENXIO;
if (flags & MF_COUNT_INCREASED)
/*
@@ -1677,73 +1757,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
put_page(page);
/* device metadata space is not recoverable */
- if (!pgmap_pfn_valid(pgmap, pfn)) {
- rc = -ENXIO;
- goto out;
- }
-
- /*
- * Pages instantiated by device-dax (not filesystem-dax)
- * may be compound pages.
- */
- page = compound_head(page);
-
- /*
- * Prevent the inode from being freed while we are interrogating
- * the address_space, typically this would be handled by
- * lock_page(), but dax pages do not use the page lock. This
- * also prevents changes to the mapping of this pfn until
- * poison signaling is complete.
- */
- cookie = dax_lock_page(page);
- if (!cookie)
+ if (!pgmap_pfn_valid(pgmap, pfn))
goto out;
- if (hwpoison_filter(page)) {
- rc = -EOPNOTSUPP;
- goto unlock;
- }
-
- if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
- /*
- * TODO: Handle HMM pages which may need coordination
- * with device-side memory.
- */
- goto unlock;
- }
-
- /*
- * Use this flag as an indication that the dax page has been
- * remapped UC to prevent speculative consumption of poison.
- */
- SetPageHWPoison(page);
-
- /*
- * Unlike System-RAM there is no possibility to swap in a
- * different physical page at a given virtual address, so all
- * userspace consumption of ZONE_DEVICE memory necessitates
- * SIGBUS (i.e. MF_MUST_KILL)
- */
- flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
- collect_procs(page, &tokill, true);
-
- list_for_each_entry(tk, &tokill, nd)
- if (tk->size_shift)
- size = max(size, 1UL << tk->size_shift);
- if (size) {
- /*
- * Unmap the largest mapping to avoid breaking up
- * device-dax mappings which are constant size. The
- * actual size of the mapping being torn down is
- * communicated in siginfo, see kill_proc()
- */
- start = (page->index << PAGE_SHIFT) & ~(size - 1);
- unmap_mapping_range(page->mapping, start, size, 0);
- }
- kill_procs(&tokill, true, false, pfn, flags);
- rc = 0;
-unlock:
- dax_unlock_page(page, cookie);
+ rc = mf_generic_kill_procs(pfn, flags, pgmap);
out:
/* drop pgmap ref acquired in caller */
put_dev_pagemap(pgmap);
--
2.35.1
在 2022/4/11 14:37, Christoph Hellwig 写道:
>> + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
>> +unlock:
>> + dax_unlock_page(page, cookie);
>> + return 0;
>
> As the buildbot points out this should probably be a "return rc".
Yes, my mistake, when resolving the conflict with latest code.
--
Thanks,
Ruan
Hi Shiyang,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on hnaz-mm/master]
[also build test WARNING on next-20220408]
[cannot apply to xfs-linux/for-next linus/master linux/master v5.18-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Shiyang-Ruan/fsdax-introduce-fs-query-to-support-reflink/20220411-001048
base: https://github.com/hnaz/linux-mm master
config: x86_64-randconfig-a011 (https://download.01.org/0day-ci/archive/20220411/[email protected]/config)
compiler: gcc-11 (Debian 11.2.0-19) 11.2.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/9ab00d3f6d4d9d3d2e4446480567af17c8726bd2
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Shiyang-Ruan/fsdax-introduce-fs-query-to-support-reflink/20220411-001048
git checkout 9ab00d3f6d4d9d3d2e4446480567af17c8726bd2
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
mm/memory-failure.c: In function 'mf_generic_kill_procs':
>> mm/memory-failure.c:1533:13: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
1533 | int rc = 0;
| ^~
vim +/rc +1533 mm/memory-failure.c
1526
1527 static int mf_generic_kill_procs(unsigned long long pfn, int flags,
1528 struct dev_pagemap *pgmap)
1529 {
1530 struct page *page = pfn_to_page(pfn);
1531 LIST_HEAD(to_kill);
1532 dax_entry_t cookie;
> 1533 int rc = 0;
1534
1535 /*
1536 * Pages instantiated by device-dax (not filesystem-dax)
1537 * may be compound pages.
1538 */
1539 page = compound_head(page);
1540
1541 /*
1542 * Prevent the inode from being freed while we are interrogating
1543 * the address_space, typically this would be handled by
1544 * lock_page(), but dax pages do not use the page lock. This
1545 * also prevents changes to the mapping of this pfn until
1546 * poison signaling is complete.
1547 */
1548 cookie = dax_lock_page(page);
1549 if (!cookie)
1550 return -EBUSY;
1551
1552 if (hwpoison_filter(page)) {
1553 rc = -EOPNOTSUPP;
1554 goto unlock;
1555 }
1556
1557 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
1558 /*
1559 * TODO: Handle HMM pages which may need coordination
1560 * with device-side memory.
1561 */
1562 return -EBUSY;
1563 }
1564
1565 /*
1566 * Use this flag as an indication that the dax page has been
1567 * remapped UC to prevent speculative consumption of poison.
1568 */
1569 SetPageHWPoison(page);
1570
1571 /*
1572 * Unlike System-RAM there is no possibility to swap in a
1573 * different physical page at a given virtual address, so all
1574 * userspace consumption of ZONE_DEVICE memory necessitates
1575 * SIGBUS (i.e. MF_MUST_KILL)
1576 */
1577 flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
1578 collect_procs(page, &to_kill, true);
1579
1580 unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
1581 unlock:
1582 dax_unlock_page(page, cookie);
1583 return 0;
1584 }
1585
--
0-DAY CI Kernel Test Service
https://01.org/lkp
> + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags);
> +unlock:
> + dax_unlock_page(page, cookie);
> + return 0;
As the buildbot points out this should probably be a "return rc".