Re: [PATCH v2 3/7] mm: introduce do_zap_pte_range()
From: Qi Zheng
Date: Wed Nov 13 2024 - 07:20:59 EST
On 2024/11/13 19:43, David Hildenbrand wrote:
On 13.11.24 03:40, Qi Zheng wrote:
On 2024/11/13 01:00, David Hildenbrand wrote:
On 31.10.24 09:13, Qi Zheng wrote:
This commit introduces do_zap_pte_range() to actually zap the PTEs,
which
will help improve code readability and facilitate secondary checking of
the processed PTEs in the future.
No functional change.
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
---
mm/memory.c | 45 ++++++++++++++++++++++++++-------------------
1 file changed, 26 insertions(+), 19 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index bd9ebe0f4471f..c1150e62dd073 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1657,6 +1657,27 @@ static inline int zap_nonpresent_ptes(struct
mmu_gather *tlb,
return nr;
}
+static inline int do_zap_pte_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pte_t *pte,
+ unsigned long addr, unsigned long end,
+ struct zap_details *details, int *rss,
+ bool *force_flush, bool *force_break)
+{
+ pte_t ptent = ptep_get(pte);
+ int max_nr = (end - addr) / PAGE_SIZE;
+
+ if (pte_none(ptent))
+ return 1;
Maybe we should just skip all applicable pte_none() here directly.
Do you mean we should keep pte_none() case in zap_pte_range()? Like
below:
No rather an addon patch that will simply skip over all
consecutive pte_none, like:
if (pte_none(ptent)) {
int nr;
for (nr = 1; nr < max_nr; nr++) {
ptent = ptep_get(pte + nr);
if (pte_none(ptent))
continue;
}
max_nr -= nr;
if (!max_nr)
return nr;
addr += nr * PAGE_SIZE;
pte += nr;
}
Assuming that it's likely more common to have larger pte_none() holes
that single ones, optimizing out the
need_resched()+force_break+incremental pte/addr increments etc.
Ah, got it. And I agree with you, will change to it in the next version.
Thanks!