| Message ID | 202302100916423431376@zte.com.cn (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ksm: support tracking KSM-placed zero-pages | expand |
On Fri, 10 Feb 2023 09:16:42 +0800 (CST) <yang.yang29@zte.com.cn> wrote: > From: xu xin <xu.xin16@zte.com.cn> > > A new function try_to_get_old_rmap_item is abstracted from > get_next_rmap_item. This function will be reused by the subsequent > patches about counting ksm_zero_pages. > > The patch improves the readability and reusability of KSM code. > > Signed-off-by: xu xin <xu.xin16@zte.com.cn> > Cc: David Hildenbrand <david@redhat.com> > Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> > Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> > Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> > Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> > > v5->v6: > Modify some comments according to David's suggestions. > --- > mm/ksm.c | 27 +++++++++++++++++++++------ > 1 file changed, 21 insertions(+), 6 deletions(-) > > diff --git a/mm/ksm.c b/mm/ksm.c > index 83e2f74ae7da..905a79d213da 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -2214,23 +2214,38 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite > } > } > > -static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, > - struct ksm_rmap_item **rmap_list, > - unsigned long addr) > +static struct ksm_rmap_item *try_to_get_old_rmap_item(unsigned long addr, > + struct ksm_rmap_item **rmap_list) > { > - struct ksm_rmap_item *rmap_item; > - > while (*rmap_list) { > - rmap_item = *rmap_list; > + struct ksm_rmap_item *rmap_item = *rmap_list; why are you declaring this here? I think it's more clear if you declare the variable at the beginning of the function, like it was before > + > if ((rmap_item->address & PAGE_MASK) == addr) > return rmap_item; > if (rmap_item->address > addr) > break; > *rmap_list = rmap_item->rmap_list; > + /* > + * If we end up here, the VMA is MADV_UNMERGEABLE or its page > + * is ineligible or discarded, e.g. MADV_DONTNEED. > + */ > remove_rmap_item_from_tree(rmap_item); > free_rmap_item(rmap_item); > } > > + return NULL; > +} > + > +static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, > + struct ksm_rmap_item **rmap_list, > + unsigned long addr) > +{ > + struct ksm_rmap_item *rmap_item; > + > + rmap_item = try_to_get_old_rmap_item(addr, rmap_list); > + if (rmap_item) > + return rmap_item; > + > rmap_item = alloc_rmap_item(); > if (rmap_item) { > /* It has already been zeroed */
diff --git a/mm/ksm.c b/mm/ksm.c index 83e2f74ae7da..905a79d213da 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2214,23 +2214,38 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite } } -static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, - struct ksm_rmap_item **rmap_list, - unsigned long addr) +static struct ksm_rmap_item *try_to_get_old_rmap_item(unsigned long addr, + struct ksm_rmap_item **rmap_list) { - struct ksm_rmap_item *rmap_item; - while (*rmap_list) { - rmap_item = *rmap_list; + struct ksm_rmap_item *rmap_item = *rmap_list; + if ((rmap_item->address & PAGE_MASK) == addr) return rmap_item; if (rmap_item->address > addr) break; *rmap_list = rmap_item->rmap_list; + /* + * If we end up here, the VMA is MADV_UNMERGEABLE or its page + * is ineligible or discarded, e.g. MADV_DONTNEED. + */ remove_rmap_item_from_tree(rmap_item); free_rmap_item(rmap_item); } + return NULL; +} + +static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, + struct ksm_rmap_item **rmap_list, + unsigned long addr) +{ + struct ksm_rmap_item *rmap_item; + + rmap_item = try_to_get_old_rmap_item(addr, rmap_list); + if (rmap_item) + return rmap_item; + rmap_item = alloc_rmap_item(); if (rmap_item) { /* It has already been zeroed */