Messages in this thread | | | Date | Tue, 7 Mar 2023 09:22:33 +0800 | Subject | Re: [PATCH v2 2/3] mm/damon/paddr: minor refactor of damon_pa_young() | From | Kefeng Wang <> |
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On 2023/3/7 5:27, SeongJae Park wrote: > Hi Kefeng, > > On Mon, 6 Mar 2023 09:56:49 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote: > >> >> >> On 2023/3/6 9:10, Kefeng Wang wrote: >>> >>> >>> On 2023/3/4 2:39, SeongJae Park wrote: >>>> Hi Kefeng, >>>> >>>> On Fri, 3 Mar 2023 16:43:42 +0800 Kefeng Wang >>>> <wangkefeng.wang@huawei.com> wrote: >>>> >>>>> Omit three lines by unified folio_put(), and make code more clear. >>>>> >>>>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >>>>> --- >>>>> mm/damon/paddr.c | 11 ++++------- >>>>> 1 file changed, 4 insertions(+), 7 deletions(-) >>>>> >>>>> diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c >>>>> index 3fda00a0f786..2ef9db0189ca 100644 >>>>> --- a/mm/damon/paddr.c >>>>> +++ b/mm/damon/paddr.c >>>>> @@ -130,24 +130,21 @@ static bool damon_pa_young(unsigned long paddr, >>>>> unsigned long *folio_sz) >>>>> accessed = false; >>>>> else >>>>> accessed = true; >>>>> - folio_put(folio); >>>>> goto out; >>>> >>>> Because you moved 'out' label to not include *folio_sz setting, >>>> folio_sz will >>>> not set in this case. It should be set. >>> oh, it should be fixed. >>>> >>>>> } >>>>> need_lock = !folio_test_anon(folio) || folio_test_ksm(folio); >>>>> - if (need_lock && !folio_trylock(folio)) { >>>>> - folio_put(folio); >>>>> - return false; >>>>> - } >> >> Hi SJ, apart from above issue, it looks that this branch need the >> folio_size() setting, right? > > folio_sz is effectively used by caller of damon_pa_young() only if this > function returns true, so this branch doesn't need to set folio_sz.
__damon_pa_check_access() store last_addr, last_accessed and last_folio_sz, even damon_pa_young() return false, the following check still use last_folio_sz,
ALIGN_DOWN(last_addr, last_folio_sz) == ALIGN_DOWN(r->sampling_addr, last_folio_sz)
but last_folio_sz is not up to date, so I think it need to update, and update last_folio_sz is harmless, which could let's unify the return path, correct me if I am wrong.
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