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AJvYcCUbGW6YixmmHVJKPyoSQdzv2Qa0UZ5/O2mg2/PwcLOkCYkWDjTmqT/ogUoPUdya9lf32ZouiaDI85b3jJTFCk3mYj4= X-Gm-Message-State: AOJu0Yx4GFbMahJtsPuBwnZzRFQxF2k6IJJxtbTaLkzEZyBtJ+pEfFRO KfWRes8yQHyEthlAqzEIE/b1kXubDvyIRAzljzO7pmqgsMzc6dBIyTJZ3oSJjoCwv7cf7lBRKAP vRc37jBdP1dj9GX1OHFk4htProCM= X-Google-Smtp-Source: AGHT+IFA0QAC0jQwNYVUYeAL9ghcZWctuTIiC8wIocajR135msiyIBXAIbpojWrWryNqi6Z5hHTJ265EnUGHLcyIegk= X-Received: by 2002:ac2:4c86:0:b0:518:6ea2:a2a3 with SMTP id d6-20020ac24c86000000b005186ea2a2a3mr9198678lfl.54.1713327229200; Tue, 16 Apr 2024 21:13:49 -0700 (PDT) MIME-Version: 1.0 References: <20240416033457.32154-1-ioworker0@gmail.com> <20240416033457.32154-2-ioworker0@gmail.com> <3c4b1711-5a84-4e7a-b54a-d4955d62ec59@arm.com> In-Reply-To: <3c4b1711-5a84-4e7a-b54a-d4955d62ec59@arm.com> From: Lance Yang Date: Wed, 17 Apr 2024 12:13:37 +0800 Message-ID: Subject: Re: [PATCH v7 1/3] mm/madvise: introduce clear_young_dirty_ptes() batch helper To: Ryan Roberts Cc: akpm@linux-foundation.org, david@redhat.com, 21cnbao@gmail.com, mhocko@suse.com, fengwei.yin@intel.com, zokeefe@google.com, shy828301@gmail.com, xiehuan09@gmail.com, wangkefeng.wang@huawei.com, songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 02B60100006 X-Stat-Signature: qc4fwdbetwpdois1fouqp9qir1dqq8ub X-HE-Tag: 1713327230-291669 X-HE-Meta: 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 LO52PfMT Nmwro7DN7FUnRZRWZ4KB5Z1Yu2Vk+DD1tJEjlrYZORCA3JQapD3/igmN9m9KdjBDCoOdvesFTZm6jJh/GNPkPGrat9zOS50XCOWO4b26wTMQ4J1U+qyZ1YuplJE151alsS38tp47AAPwPyWZvjR2HcEUi+KLSzFbL+vRrbxSvIjj+B9z4z9MDLROZcrp5pDi/ivDFaihrHqcuF9AWukmtx+5cOVIqJgFBhWbq/TxG6oIvDL1fagHTkcuvc3Y1dPBo5g+8R/7Al3LD+PDXY36NP13shwDLwvO/QCrlCjbiCkopDBSY40U8p3HseQwyXhfdlPIvSxN8eaELhcEZWC6BD6iXGXu2zGtWPgelL6j1fb3p+YNdPsWQYYF7o944uVz0ni/Jcczm6hUToU2rLoTquPr/kNDfey+LgmpKMGnKQnHd9aYwnJfFxzGNTc69Bevc9TH0vCDd5P+8RB2KtGd7pWfL9EsR75esXATLCGHfIOFkoYo= 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: On Wed, Apr 17, 2024 at 12:25=E2=80=AFAM Ryan Roberts wrote: > > On 16/04/2024 04:34, Lance Yang wrote: > > This commit introduces clear_young_dirty_ptes() to replace mkold_ptes()= . > > By doing so, we can use the same function for both use cases > > (madvise_pageout and madvise_free), and it also provides the flexibilit= y > > to only clear the dirty flag in the future if needed. > > > > Suggested-by: Ryan Roberts > > Signed-off-by: Lance Yang > > Reviewed-by: Ryan Roberts Hey Ryan, Thanks for taking time to review! Best, Lance > > > --- > > include/linux/mm_types.h | 9 +++++ > > include/linux/pgtable.h | 74 ++++++++++++++++++++++++---------------- > > mm/madvise.c | 3 +- > > 3 files changed, 55 insertions(+), 31 deletions(-) > > > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > > index c432add95913..28822cd65d2a 100644 > > --- a/include/linux/mm_types.h > > +++ b/include/linux/mm_types.h > > @@ -1367,6 +1367,15 @@ enum fault_flag { > > > > typedef unsigned int __bitwise zap_flags_t; > > > > +/* Flags for clear_young_dirty_ptes(). */ > > +typedef int __bitwise cydp_t; > > + > > +/* Clear the access bit */ > > +#define CYDP_CLEAR_YOUNG ((__force cydp_t)BIT(0)) > > + > > +/* Clear the dirty bit */ > > +#define CYDP_CLEAR_DIRTY ((__force cydp_t)BIT(1)) > > + > > /* > > * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with= each > > * other. Here is what they mean, and how to use them: > > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > > index e2f45e22a6d1..18019f037bae 100644 > > --- a/include/linux/pgtable.h > > +++ b/include/linux/pgtable.h > > @@ -361,36 +361,6 @@ static inline int ptep_test_and_clear_young(struct= vm_area_struct *vma, > > } > > #endif > > > > -#ifndef mkold_ptes > > -/** > > - * mkold_ptes - Mark PTEs that map consecutive pages of the same folio= as old. > > - * @vma: VMA the pages are mapped into. > > - * @addr: Address the first page is mapped at. > > - * @ptep: Page table pointer for the first entry. > > - * @nr: Number of entries to mark old. > > - * > > - * May be overridden by the architecture; otherwise, implemented as a = simple > > - * loop over ptep_test_and_clear_young(). > > - * > > - * Note that PTE bits in the PTE range besides the PFN can differ. For= example, > > - * some PTEs might be write-protected. > > - * > > - * Context: The caller holds the page table lock. The PTEs map consec= utive > > - * pages that belong to the same folio. The PTEs are all in the same = PMD. > > - */ > > -static inline void mkold_ptes(struct vm_area_struct *vma, unsigned lon= g addr, > > - pte_t *ptep, unsigned int nr) > > -{ > > - for (;;) { > > - ptep_test_and_clear_young(vma, addr, ptep); > > - if (--nr =3D=3D 0) > > - break; > > - ptep++; > > - addr +=3D PAGE_SIZE; > > - } > > -} > > -#endif > > - > > #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG > > #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NO= NLEAF_PMD_YOUNG) > > static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma= , > > @@ -489,6 +459,50 @@ static inline pte_t ptep_get_and_clear(struct mm_s= truct *mm, > > } > > #endif > > > > +#ifndef clear_young_dirty_ptes > > +/** > > + * clear_young_dirty_ptes - Mark PTEs that map consecutive pages of th= e > > + * same folio as old/clean. > > + * @mm: Address space the pages are mapped into. > > + * @addr: Address the first page is mapped at. > > + * @ptep: Page table pointer for the first entry. > > + * @nr: Number of entries to mark old/clean. > > + * @flags: Flags to modify the PTE batch semantics. > > + * > > + * May be overridden by the architecture; otherwise, implemented by > > + * get_and_clear/modify/set for each pte in the range. > > + * > > + * Note that PTE bits in the PTE range besides the PFN can differ. For= example, > > + * some PTEs might be write-protected. > > + * > > + * Context: The caller holds the page table lock. The PTEs map consec= utive > > + * pages that belong to the same folio. The PTEs are all in the same = PMD. > > + */ > > +static inline void clear_young_dirty_ptes(struct vm_area_struct *vma, > > + unsigned long addr, pte_t *ptep= , > > + unsigned int nr, cydp_t flags) > > +{ > > + pte_t pte; > > + > > + for (;;) { > > + if (flags =3D=3D CYDP_CLEAR_YOUNG) > > + ptep_test_and_clear_young(vma, addr, ptep); > > + else { > > + pte =3D ptep_get_and_clear(vma->vm_mm, addr, ptep= ); > > + if (flags & CYDP_CLEAR_YOUNG) > > + pte =3D pte_mkold(pte); > > + if (flags & CYDP_CLEAR_DIRTY) > > + pte =3D pte_mkclean(pte); > > + set_pte_at(vma->vm_mm, addr, ptep, pte); > > + } > > + if (--nr =3D=3D 0) > > + break; > > + ptep++; > > + addr +=3D PAGE_SIZE; > > + } > > +} > > +#endif > > + > > static inline void ptep_clear(struct mm_struct *mm, unsigned long addr= , > > pte_t *ptep) > > { > > diff --git a/mm/madvise.c b/mm/madvise.c > > index f59169888b8e..edb592adb749 100644 > > --- a/mm/madvise.c > > +++ b/mm/madvise.c > > @@ -507,7 +507,8 @@ static int madvise_cold_or_pageout_pte_range(pmd_t = *pmd, > > continue; > > > > if (!pageout && pte_young(ptent)) { > > - mkold_ptes(vma, addr, pte, nr); > > + clear_young_dirty_ptes(vma, addr, pte, nr, > > + CYDP_CLEAR_YOUNG); > > tlb_remove_tlb_entries(tlb, pte, nr, addr); > > } > > >