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From: Lance Yang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4E4F98000E X-Stat-Signature: kt9pswdwitzz37ri4otgbwx3omeexea6 X-Rspam-User: X-HE-Tag: 1757946422-253248 X-HE-Meta: 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 zV7kSQ46 XtwqiQspbpH3rUdamfPebQcl5fEk6yxSZn3XzDnyM6dXAsx6trDI4zfemuUaQaRXd3hNzPs1+kQrH7wguLMUA/8GHEs3f7r5E4o+Uh7KmesWjBPYIz84tS/nX8YlB6mSslLTze3BkivPKK4lDgBYPuXdmvdJhS3O3S6L2VyAhGbUs7cggSoBI5mpYOkCUbjtrNgm2oxRGL7xGRPZGlZhzPEXPPakJ+KUVrDCaSeNIEWlBC3SuJa8q3zVgY19RXAMs5TOfTEsjMd0oloIKqOkyv2AuFrzZZPclU/ePi3BzulY78A8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Lorenzo, Thanks for taking time to review! On 2025/9/15 21:54, Lorenzo Stoakes wrote: > On Sun, Sep 14, 2025 at 10:35:46PM +0800, Lance Yang wrote: >> From: Lance Yang >> >> is_guard_pte_marker() performs a redundant check because it calls both >> is_pte_marker() and is_guard_swp_entry(), both of which internally check >> for a PTE marker. >> >> is_guard_pte_marker() >> |- is_pte_marker() >> | `- is_pte_marker_entry() // First check >> `- is_guard_swp_entry() >> `- is_pte_marker_entry() // Second, redundant check >> > > I mean, it expands to: > > is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte)) && > is_pte_marker_entry(pte_to_swp_entry(pte)) Yes, that's a much clearer way to lay it out ;) > > So I don't think it's really unreasonable to expect compiler magic here... > > But you're right that I should have just used is_swap_pte() really, it's a bit > silly not to, so this is fine :) Exactly. Glad we're on the same page! > >> While a modern compiler could likely optimize this away, let's have clean >> code and not rely on it ;) > > Please don't put smileys in commit messages :) as cute as they are, this is > going on the permanent kernel record and while we all love them, it's > probably not the best place to put them :P > >> >> Also, make it available for hugepage collapsing code. > > Nit but put a newline after this. Got it. Will fix up all nits in v2. > > I think probably if I'm really really nitty I'd say that you should put > this bit first, as it's the primary motivation for the change, and put the > refactoring stuff after. Ah, right. The motivation for exposing the helper should come first. I'll reorder this changelog in v2. > >> Cc: Kairui Song >> Signed-off-by: Lance Yang > > This seems fine to me, so: > > Reviewed-by: Lorenzo Stoakes Thanks, Lance > >> --- >> include/linux/swapops.h | 6 ++++++ >> mm/madvise.c | 6 ------ >> 2 files changed, 6 insertions(+), 6 deletions(-) >> >> diff --git a/include/linux/swapops.h b/include/linux/swapops.h >> index 59c5889a4d54..7f5684fa043b 100644 >> --- a/include/linux/swapops.h >> +++ b/include/linux/swapops.h >> @@ -469,6 +469,12 @@ static inline int is_guard_swp_entry(swp_entry_t entry) >> (pte_marker_get(entry) & PTE_MARKER_GUARD); >> } >> >> +static inline bool is_guard_pte_marker(pte_t ptent) >> +{ >> + return is_swap_pte(ptent) && >> + is_guard_swp_entry(pte_to_swp_entry(ptent)); >> +} >> + >> /* >> * This is a special version to check pte_none() just to cover the case when >> * the pte is a pte marker. It existed because in many cases the pte marker >> diff --git a/mm/madvise.c b/mm/madvise.c >> index 35ed4ab0d7c5..bd46e6788fac 100644 >> --- a/mm/madvise.c >> +++ b/mm/madvise.c >> @@ -1069,12 +1069,6 @@ static bool is_valid_guard_vma(struct vm_area_struct *vma, bool allow_locked) >> return !(vma->vm_flags & disallowed); >> } >> >> -static bool is_guard_pte_marker(pte_t ptent) >> -{ >> - return is_pte_marker(ptent) && >> - is_guard_swp_entry(pte_to_swp_entry(ptent)); >> -} >> - >> static int guard_install_pud_entry(pud_t *pud, unsigned long addr, >> unsigned long next, struct mm_walk *walk) >> { >> -- >> 2.49.0 >>