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Message-Id: <20221109102303.851281-2-usama.anjum@collabora.com>
Date: Wed, 9 Nov 2022 15:23:01 +0500
From: Muhammad Usama Anjum <usama.anjum@...labora.com>
To: Michał Mirosław <emmir@...gle.com>,
Andrei Vagin <avagin@...il.com>,
Danylo Mocherniuk <mdanylo@...gle.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Suren Baghdasaryan <surenb@...gle.com>,
Greg KH <gregkh@...uxfoundation.org>,
Christian Brauner <brauner@...nel.org>,
Peter Xu <peterx@...hat.com>, Yang Shi <shy828301@...il.com>,
Vlastimil Babka <vbabka@...e.cz>,
"Zach O'Keefe" <zokeefe@...gle.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
"Gustavo A. R. Silva" <gustavoars@...nel.org>,
Dan Williams <dan.j.williams@...el.com>,
Muhammad Usama Anjum <usama.anjum@...labora.com>,
kernel@...labora.com,
Gabriel Krisman Bertazi <krisman@...labora.com>,
David Hildenbrand <david@...hat.com>,
Peter Enderborg <peter.enderborg@...y.com>,
"open list : KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@...r.kernel.org>, Shuah Khan <shuah@...nel.org>,
open list <linux-kernel@...r.kernel.org>,
"open list : PROC FILESYSTEM" <linux-fsdevel@...r.kernel.org>,
"open list : MEMORY MANAGEMENT" <linux-mm@...ck.org>,
Paul Gofman <pgofman@...eweavers.com>
Subject: [PATCH v6 1/3] fs/proc/task_mmu: update functions to clear the soft-dirty PTE bit
Update the clear_soft_dirty() and clear_soft_dirty_pmd() to optionally
clear and return the status if page is dirty.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@...labora.com>
---
Changes in v2:
- Move back the functions back to their original file
---
fs/proc/task_mmu.c | 82 ++++++++++++++++++++++++++++------------------
1 file changed, 51 insertions(+), 31 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8a74cdcc9af0..8235c536ac70 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1095,8 +1095,8 @@ static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr,
return page_maybe_dma_pinned(page);
}
-static inline void clear_soft_dirty(struct vm_area_struct *vma,
- unsigned long addr, pte_t *pte)
+static inline bool check_soft_dirty(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *pte, bool clear)
{
/*
* The soft-dirty tracker uses #PF-s to catch writes
@@ -1105,55 +1105,75 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
* of how soft-dirty works.
*/
pte_t ptent = *pte;
+ int dirty = 0;
if (pte_present(ptent)) {
pte_t old_pte;
- if (pte_is_pinned(vma, addr, ptent))
- return;
- old_pte = ptep_modify_prot_start(vma, addr, pte);
- ptent = pte_wrprotect(old_pte);
- ptent = pte_clear_soft_dirty(ptent);
- ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
+ dirty = pte_soft_dirty(ptent);
+
+ if (dirty && clear && !pte_is_pinned(vma, addr, ptent)) {
+ old_pte = ptep_modify_prot_start(vma, addr, pte);
+ ptent = pte_wrprotect(old_pte);
+ ptent = pte_clear_soft_dirty(ptent);
+ ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
+ }
} else if (is_swap_pte(ptent)) {
- ptent = pte_swp_clear_soft_dirty(ptent);
- set_pte_at(vma->vm_mm, addr, pte, ptent);
+ dirty = pte_swp_soft_dirty(ptent);
+
+ if (dirty && clear) {
+ ptent = pte_swp_clear_soft_dirty(ptent);
+ set_pte_at(vma->vm_mm, addr, pte, ptent);
+ }
}
+
+ return !!dirty;
}
#else
-static inline void clear_soft_dirty(struct vm_area_struct *vma,
- unsigned long addr, pte_t *pte)
+static inline bool check_soft_dirty(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *pte, bool clear)
{
+ return false;
}
#endif
#if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
-static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
- unsigned long addr, pmd_t *pmdp)
+static inline bool check_soft_dirty_pmd(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmdp, bool clear)
{
pmd_t old, pmd = *pmdp;
+ int dirty = 0;
if (pmd_present(pmd)) {
- /* See comment in change_huge_pmd() */
- old = pmdp_invalidate(vma, addr, pmdp);
- if (pmd_dirty(old))
- pmd = pmd_mkdirty(pmd);
- if (pmd_young(old))
- pmd = pmd_mkyoung(pmd);
-
- pmd = pmd_wrprotect(pmd);
- pmd = pmd_clear_soft_dirty(pmd);
-
- set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ dirty = pmd_soft_dirty(pmd);
+ if (dirty && clear) {
+ /* See comment in change_huge_pmd() */
+ old = pmdp_invalidate(vma, addr, pmdp);
+ if (pmd_dirty(old))
+ pmd = pmd_mkdirty(pmd);
+ if (pmd_young(old))
+ pmd = pmd_mkyoung(pmd);
+
+ pmd = pmd_wrprotect(pmd);
+ pmd = pmd_clear_soft_dirty(pmd);
+
+ set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ }
} else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
- pmd = pmd_swp_clear_soft_dirty(pmd);
- set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ dirty = pmd_swp_soft_dirty(pmd);
+
+ if (dirty && clear) {
+ pmd = pmd_swp_clear_soft_dirty(pmd);
+ set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ }
}
+ return !!dirty;
}
#else
-static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
- unsigned long addr, pmd_t *pmdp)
+static inline bool check_soft_dirty_pmd(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmdp, bool clear)
{
+ return false;
}
#endif
@@ -1169,7 +1189,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
- clear_soft_dirty_pmd(vma, addr, pmd);
+ check_soft_dirty_pmd(vma, addr, pmd, true);
goto out;
}
@@ -1195,7 +1215,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
ptent = *pte;
if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
- clear_soft_dirty(vma, addr, pte);
+ check_soft_dirty(vma, addr, pte, true);
continue;
}
--
2.30.2
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