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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko References: <20260119220708.3438514-1-david@kernel.org> <20260119220708.3438514-3-david@kernel.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: <20260119220708.3438514-3-david@kernel.org> 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: A9FC71A0009 X-Stat-Signature: rpyacz4h1qfeczrsddnz3u5mp8yc9qmp X-Rspam-User: X-HE-Tag: 1768879943-233651 X-HE-Meta: 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 EnYQJn1u PFlxqFGJreyu554Mofxdtx3hXVD5rXv/9gsJC7uR1+luMTHllZW9hHFnfVxbqrJO8VGvrV/SOCm3USkHVJsGe7coGU3F0sqrnuHy8DhpE47uF5J0xuHPst4zN2XUmhlG7GyBoo8QtzGVrUDFUzxxj5rpv/caU7ZFK2bd1PAyNAsmaGSGH+DdGxHlmRgG4zELMSP5m4zvA3AbaPc1aGXmm8v8ad3kuJZVfz7Ly0JskWt7yA6Y6+fNnht7eiDKpCzOh9IOa3ZxQvhzzlLT5DlLmf/UdFJaPDFtJMVS4oRcH+042PM5/Cdl7ehJMWq2azJF47UyYTuc0+zkYi8eFtyb6NfTluw== 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 1/20/26 6:07 AM, David Hildenbrand (Red Hat) wrote: > While we handle pte_lockptr() == pmd_lockptr() correctly in > zap_pte_table_if_empty(), we don't handle it in zap_empty_pte_table(), > making the spin_trylock() always fail and forcing us onto the slow path. > > So let's handle the scenario where pte_lockptr() == pmd_lockptr() > better, which can only happen if CONFIG_SPLIT_PTE_PTLOCKS is not set. > > This is only relevant once we unlock CONFIG_PT_RECLAIM on architectures > that are not x86-64. > > Signed-off-by: David Hildenbrand (Red Hat) > --- > mm/memory.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) Reviewed-by: Qi Zheng Thanks! > > diff --git a/mm/memory.c b/mm/memory.c > index c3055b2577c27..3852075ea62d4 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1833,16 +1833,18 @@ static bool pte_table_reclaim_possible(unsigned long start, unsigned long end, > return details && details->reclaim_pt && (end - start >= PMD_SIZE); > } > > -static bool zap_empty_pte_table(struct mm_struct *mm, pmd_t *pmd, pmd_t *pmdval) > +static bool zap_empty_pte_table(struct mm_struct *mm, pmd_t *pmd, > + spinlock_t *ptl, pmd_t *pmdval) > { > spinlock_t *pml = pmd_lockptr(mm, pmd); > > - if (!spin_trylock(pml)) > + if (ptl != pml && !spin_trylock(pml)) > return false; > > *pmdval = pmdp_get(pmd); > pmd_clear(pmd); > - spin_unlock(pml); > + if (ptl != pml) > + spin_unlock(pml); > return true; > } > > @@ -1934,7 +1936,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, > * from being repopulated by another thread. > */ > if (can_reclaim_pt && direct_reclaim && addr == end) > - direct_reclaim = zap_empty_pte_table(mm, pmd, &pmdval); > + direct_reclaim = zap_empty_pte_table(mm, pmd, ptl, &pmdval); > > add_mm_rss_vec(mm, rss); > lazy_mmu_mode_disable();