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From: Chinwen Chang <chinwen.chang@mediatek.com>
To: Matthias Brugger <matthias.bgg@gmail.com>,
	Michel Lespinasse <walken@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Daniel Jordan <daniel.m.jordan@oracle.com>,
	Davidlohr Bueso <dbueso@suse.de>,
	Chinwen Chang <chinwen.chang@mediatek.com>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Steven Price <steven.price@arm.com>,
	Song Liu <songliubraving@fb.com>,
	Jimmy Assarsson <jimmyassarsson@gmail.com>,
	Huang Ying <ying.huang@intel.com>,
	Daniel Kiss <daniel.kiss@arm.com>,
	Laurent Dufour <ldufour@linux.ibm.com>
Cc: <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	<linux-fsdevel@vger.kernel.org>, <wsd_upstream@mediatek.com>
Subject: [PATCH v4 2/3] mm: smaps*: extend smap_gather_stats to support specified beginning
Date: Tue, 18 Aug 2020 09:58:17 +0800	[thread overview]
Message-ID: <1597715898-3854-3-git-send-email-chinwen.chang@mediatek.com> (raw)
In-Reply-To: <1597715898-3854-1-git-send-email-chinwen.chang@mediatek.com>

Extend smap_gather_stats to support indicated beginning address at
which it should start gathering. To achieve the goal, we add a new
parameter @start assigned by the caller and try to refactor it for
simplicity.

If @start is 0, it will use the range of @vma for gathering.

Change since v2:
- This is a new change to make the retry behavior of smaps_rollup
- more complete as suggested by Michel [1]

[1] https://lore.kernel.org/lkml/CANN689FtCsC71cjAjs0GPspOhgo_HRj+diWsoU1wr98YPktgWg@mail.gmail.com/

Signed-off-by: Chinwen Chang <chinwen.chang@mediatek.com>
CC: Michel Lespinasse <walken@google.com>
Reviewed-by: Steven Price <steven.price@arm.com>
---
 fs/proc/task_mmu.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index dbda449..76e623a 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -723,9 +723,21 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 	.pte_hole		= smaps_pte_hole,
 };
 
+/*
+ * Gather mem stats from @vma with the indicated beginning
+ * address @start, and keep them in @mss.
+ *
+ * Use vm_start of @vma as the beginning address if @start is 0.
+ */
 static void smap_gather_stats(struct vm_area_struct *vma,
-			     struct mem_size_stats *mss)
+		struct mem_size_stats *mss, unsigned long start)
 {
+	const struct mm_walk_ops *ops = &smaps_walk_ops;
+
+	/* Invalid start */
+	if (start >= vma->vm_end)
+		return;
+
 #ifdef CONFIG_SHMEM
 	/* In case of smaps_rollup, reset the value from previous vma */
 	mss->check_shmem_swap = false;
@@ -742,18 +754,20 @@ static void smap_gather_stats(struct vm_area_struct *vma,
 		 */
 		unsigned long shmem_swapped = shmem_swap_usage(vma);
 
-		if (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
-					!(vma->vm_flags & VM_WRITE)) {
+		if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
+					!(vma->vm_flags & VM_WRITE))) {
 			mss->swap += shmem_swapped;
 		} else {
 			mss->check_shmem_swap = true;
-			walk_page_vma(vma, &smaps_shmem_walk_ops, mss);
-			return;
+			ops = &smaps_shmem_walk_ops;
 		}
 	}
 #endif
 	/* mmap_lock is held in m_start */
-	walk_page_vma(vma, &smaps_walk_ops, mss);
+	if (!start)
+		walk_page_vma(vma, ops, mss);
+	else
+		walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
 }
 
 #define SEQ_PUT_DEC(str, val) \
@@ -805,7 +819,7 @@ static int show_smap(struct seq_file *m, void *v)
 
 	memset(&mss, 0, sizeof(mss));
 
-	smap_gather_stats(vma, &mss);
+	smap_gather_stats(vma, &mss, 0);
 
 	show_map_vma(m, vma);
 
@@ -854,7 +868,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 	hold_task_mempolicy(priv);
 
 	for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
-		smap_gather_stats(vma, &mss);
+		smap_gather_stats(vma, &mss, 0);
 		last_vma_end = vma->vm_end;
 	}
 
-- 
1.9.1

  parent reply	other threads:[~2020-08-18  1:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18  1:58 [PATCH v4 0/3] Try to release mmap_lock temporarily in smaps_rollup Chinwen Chang
2020-08-18  1:58 ` [PATCH v4 1/3] mmap locking API: add mmap_lock_is_contended() Chinwen Chang
2020-08-18  1:58 ` Chinwen Chang [this message]
2020-08-18  1:58 ` [PATCH v4 3/3] mm: proc: smaps_rollup: do not stall write attempts on mmap_lock Chinwen Chang
2020-08-19  7:37   ` Steven Price

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