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V.'s message of "Sun, 03 Mar 2024 11:47:47 +0530") References: <9c3f7b743477560d1c5b12b8c111a584a2cc92ee.1708097962.git.donettom@linux.ibm.com> <20240218133851.22c22b55460e866a099be5ce@linux-foundation.org> <63a0f7c4-3c3f-4097-9a24-d1e3fc7b6030@linux.ibm.com> <20240219172130.82a16c1ebecbf8ba86a8987d@linux-foundation.org> <21f343fa-84a7-4539-91e2-6fc963dbfb62@kernel.org> <87frxnps8w.fsf@yhuang6-desk2.ccr.corp.intel.com> <7097ff95-6077-4744-a770-b90d224c0c9b@kernel.org> <8734tnppls.fsf@yhuang6-desk2.ccr.corp.intel.com> <875xy3ltys.fsf@kernel.org> Date: Mon, 04 Mar 2024 09:49:54 +0800 Message-ID: <87sf16bwal.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 222A7C000A X-Stat-Signature: pm7cr8qt1jnjfhnmmpmaks85piej9rnw X-HE-Tag: 1709517115-256934 X-HE-Meta: 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 i7vI0t31 /1D2VJzqllU654ch5GbCVZYK31gLDC1fmW5knX26aBa6GhVHjgN8amTWjke16Pc4EPzCF0x5bj0+3G54Z1NFmW8iDOHq8FpoWbaWVW9+jrpBAwNhfXdJJcrWuRrXJwtFeWSqb3EMW4dVl/T8wtx9dz5H85AL1Le25vwd004b1yEzn2fx0u7mIN2otC3U5b9qbbjsOQLPW3j4GBnXFZqL3CGtolI+0gyEhHqYOH/E1ckV8thzuI5WdvzuDxRk0sXQuz/hW9zNtKxG99NtUM2kSdZlcF14i31wUyrqJ 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: Aneesh Kumar K.V writes: > Michal Hocko writes: > >> On Tue 20-02-24 15:22:07, Huang, Ying wrote: >> [...] >>> This isn't an issue now, because mpol_misplaced() are always called with >>> PTL held. And, we can still keep thiscpu local variable. >> >> yes, this is the case but it would be better if we made that assumption >> official by lockdep_assert_held >> > > How about this folded into this patch? > > 2 files changed, 12 insertions(+), 4 deletions(-) > mm/memory.c | 6 ++++-- > mm/mempolicy.c | 10 ++++++++-- > > modified mm/memory.c > @@ -4879,9 +4879,11 @@ static vm_fault_t do_fault(struct vm_fault *vmf) > return ret; > } > > -int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma, > +int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf, > unsigned long addr, int page_nid, int *flags) > { > + struct vm_area_struct *vma = vmf->vma; > + > folio_get(folio); > > /* Record the current PID acceesing VMA */ > @@ -4893,7 +4895,7 @@ int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma, > *flags |= TNF_FAULT_LOCAL; > } > > - return mpol_misplaced(folio, vma, addr); > + return mpol_misplaced(folio, vmf, addr); > } > > static vm_fault_t do_numa_page(struct vm_fault *vmf) > modified mm/mempolicy.c > @@ -2495,18 +2495,24 @@ static inline bool mpol_preferred_should_numa_migrate(int exec_node, int folio_n > * Return: NUMA_NO_NODE if the page is in a node that is valid for this > * policy, or a suitable node ID to allocate a replacement folio from. > */ > -int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma, > +int mpol_misplaced(struct folio *folio, struct vm_fault *vmf, > unsigned long addr) > { > struct mempolicy *pol; > pgoff_t ilx; > struct zoneref *z; > int curnid = folio_nid(folio); > + struct vm_area_struct *vma = vmf->vma; > int thiscpu = raw_smp_processor_id(); > - int thisnid = cpu_to_node(thiscpu); > + int thisnid = numa_node_id(); > int polnid = NUMA_NO_NODE; > int ret = NUMA_NO_NODE; > > + /* > + * Make sure ptl is held so that we don't preempt and we > + * have a stable smp processor id > + */ > + lockdep_assert_held(vmf->ptl); > pol = get_vma_policy(vma, addr, folio_order(folio), &ilx); > if (!(pol->flags & MPOL_F_MOF)) > goto out; > > [back] > LGTM, Thanks! -- Best Regards, Huang, Ying