From: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
torvalds@linux-foundation.org, kirill@shutemov.name
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Subject: [RFC PATCH 1/4] mm: Have the mempolicy pagewalk to avoid positive callback return codes
Date: Thu, 10 Oct 2019 15:40:55 +0200 [thread overview]
Message-ID: <20191010134058.11949-2-thomas_os@shipmail.org> (raw)
In-Reply-To: <20191010134058.11949-1-thomas_os@shipmail.org>
From: Linus Torvalds <torvalds@linux-foundation.org>
The pagewalk code is being reworked to have positive callback return codes
do walk control. Avoid using positive return codes: "1" is replaced by
"-EBUSY".
Co-developed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
---
mm/mempolicy.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4ae967bcf954..df34c7498c27 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -482,8 +482,8 @@ static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
*
* queue_pages_pte_range() has three possible return values:
* 0 - pages are placed on the right node or queued successfully.
- * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
- * specified.
+ * -EBUSY - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were
+ * specified.
* -EIO - only MPOL_MF_STRICT was specified and an existing page was already
* on a node that does not follow the policy.
*/
@@ -503,7 +503,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
if (ptl) {
ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
if (ret != 2)
- return ret;
+ return (ret == 1) ? -EBUSY : ret;
}
/* THP was split, fall through to pte walk */
@@ -546,7 +546,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
cond_resched();
if (has_unmovable)
- return 1;
+ return -EBUSY;
return addr != end ? -EIO : 0;
}
@@ -669,9 +669,9 @@ static const struct mm_walk_ops queue_pages_walk_ops = {
* passed via @private.
*
* queue_pages_range() has three possible return values:
- * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
- * specified.
* 0 - queue pages successfully or no misplaced page.
+ * -EBUSY - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
+ * specified.
* -EIO - there is misplaced page and only MPOL_MF_STRICT was specified.
*/
static int
@@ -1285,7 +1285,7 @@ static long do_mbind(unsigned long start, unsigned long len,
ret = queue_pages_range(mm, start, end, nmask,
flags | MPOL_MF_INVERT, &pagelist);
- if (ret < 0) {
+ if (ret < 0 && ret != -EBUSY) {
err = -EIO;
goto up_out;
}
@@ -1303,7 +1303,7 @@ static long do_mbind(unsigned long start, unsigned long len,
putback_movable_pages(&pagelist);
}
- if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
+ if ((ret < 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
err = -EIO;
} else
putback_movable_pages(&pagelist);
--
2.21.0
next prev parent reply other threads:[~2019-10-10 13:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 13:40 [RFC PATCH 0/4] mm: pagewalk: Rework callback return values and optionally skip the pte level Thomas Hellström (VMware)
2019-10-10 13:40 ` Thomas Hellström (VMware) [this message]
2019-10-11 13:08 ` [RFC PATCH 1/4] mm: Have the mempolicy pagewalk to avoid positive callback return codes Kirill A. Shutemov
2019-10-10 13:40 ` [RFC PATCH 2/4] fs: task_mmu: Have the pagewalk " Thomas Hellström (VMware)
2019-10-10 13:40 ` [RFC PATCH 3/4] mm: pagewalk: Disallow user positive callback return values and use them for walk control Thomas Hellström (VMware)
2019-10-10 13:40 ` [RFC PATCH 4/4] mm: mapping_dirty_helpers: Handle huge pmds correctly Thomas Hellström (VMware)
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