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Tue, 07 Feb 2023 17:55:02 -0800 (PST) Received: from localhost ([2400:8902::f03c:93ff:fe27:642a]) by smtp.gmail.com with ESMTPSA id q20-20020a638c54000000b004eecc3080f8sm8635372pgn.29.2023.02.07.17.54.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Feb 2023 17:54:59 -0800 (PST) Date: Wed, 8 Feb 2023 01:54:47 +0000 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v4 5/7] mm: replace vma->vm_flags indirect modification in ksm_madvise Message-ID: References: <20230126193752.297968-1-surenb@google.com> <20230126193752.297968-6-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230126193752.297968-6-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 26, 2023 at 11:37:50AM -0800, Suren Baghdasaryan wrote: > Replace indirect modifications to vma->vm_flags with calls to modifier > functions to be able to track flag changes and to keep vma locking > correctness. > > Signed-off-by: Suren Baghdasaryan > Acked-by: Michal Hocko > Acked-by: Mel Gorman > Acked-by: Mike Rapoport (IBM) > --- > arch/powerpc/kvm/book3s_hv_uvmem.c | 6 +++++- > arch/s390/mm/gmap.c | 6 +++++- > 2 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c > index 1d67baa5557a..709ebd578394 100644 > --- a/arch/powerpc/kvm/book3s_hv_uvmem.c > +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c > @@ -393,6 +393,7 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, > { > unsigned long gfn = memslot->base_gfn; > unsigned long end, start = gfn_to_hva(kvm, gfn); > + unsigned long vm_flags; > int ret = 0; > struct vm_area_struct *vma; > int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE; > @@ -409,12 +410,15 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, > ret = H_STATE; > break; > } > + /* Copy vm_flags to avoid partial modifications in ksm_madvise */ > + vm_flags = vma->vm_flags; > ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, > - merge_flag, &vma->vm_flags); > + merge_flag, &vm_flags); > if (ret) { > ret = H_STATE; > break; > } > + vm_flags_reset(vma, vm_flags); > start = vma->vm_end; > } while (end > vma->vm_end); > > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index ab836597419d..5a716bdcba05 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -2587,14 +2587,18 @@ int gmap_mark_unmergeable(void) > { > struct mm_struct *mm = current->mm; > struct vm_area_struct *vma; > + unsigned long vm_flags; > int ret; > VMA_ITERATOR(vmi, mm, 0); > > for_each_vma(vmi, vma) { > + /* Copy vm_flags to avoid partial modifications in ksm_madvise */ > + vm_flags = vma->vm_flags; > ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, > - MADV_UNMERGEABLE, &vma->vm_flags); > + MADV_UNMERGEABLE, &vm_flags); > if (ret) > return ret; > + vm_flags_reset(vma, vm_flags); > } > mm->def_flags &= ~VM_MERGEABLE; > return 0; > -- Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > 2.39.1 > >