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b=vjFt0nrlOB/ft5KBo/sMOqaAq+tEOD0nuPweYTI1L+TMBmzOhi2KsDTvpCdUHMClpdQjkHRXLoIhUkx3imYlCY+4MQU5n7ebU9Eg5yog36QHzEkyi4mElR62V52A5SjCEyP4QLh+WrO8q8/pQ0qqNB4f11YTS1crPHyXbmKhi1s= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WT1p3x3_1742960303 cluster:ay36) by smtp.aliyun-inc.com; Wed, 26 Mar 2025 11:38:24 +0800 From: Baolin Wang To: akpm@linux-foundation.org, hughd@google.com Cc: willy@infradead.org, david@redhat.com, 21cnbao@gmail.com, ryan.roberts@arm.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] mm: mincore: use folio_pte_batch() to batch process large folios Date: Wed, 26 Mar 2025 11:38:11 +0800 Message-ID: <7ad05bc9299de5d954fb21a2da57f46dd6ec59d0.1742960003.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Queue-Id: 1AF1B4000C X-Stat-Signature: qz7qa6o1k1d1jxnx9u9htaxn48ny5k4t X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1742960309-39249 X-HE-Meta: U2FsdGVkX19cEbzEduEOiE3rAOXaUvh06zTsTLSZVff/fVMnV7OjU+ywxxlwaGw/8YaCg/fKQUH4xAAhPQYr4sN63ssXnnYD7HXf8eTzkXPOmySN/1xADL79+IP54h3cQTMLlYAe2sFgm46hXrKKsBJf4CnbEKD1rPIPijaOIcqgWC2/hrByPkHfF4JZMfaKejIqxEU8cOh4vO3W1p4b6O/7Vm6V+0uqKF92Es7/9C9ofb5P+6hH78xcKJJh9J0nxUsoVUAJP/Xwmt3/0MaKV8510ISK/ID+GyT2rubMJ3r3JMDgqdXvRh00/0rxxkrhwrny75CmOpyEmo3yCh3cymXI7Dx0gB7kL+Cbrrs0rNDimofzVMgwgI4paCk6Uqo8VXoqMjMA745MS4jtbMds/6C6KEmGFujibOmPkCwXevU/MSQVUfo3XSB8UNJmAHT4aJ3pshYpGni6vTR3YkvoQ7MwPXUibCQQQWG/vm2h6fuzO4480Fpm6Us5kiNGlEDB88jx+Md3dh96k3QRquTeVbsWmc3XOYhP86Vdim06rYrK7HX0x8lRJf1KpPoFpMW074yHWRrHs7F704dsMGc2y9y54qi0qXWNNJB65ATZSDTZ/SZ3SFK/j2GOReS40UCix53ZcIY4bZ5sUV2+oRmD7hZNqFsLhhtj2VgaNwiBLyPJTkclkae3dYAZyrxjaB9GC8AaHnj3SbVRr6atHKHTNJNDahzqwV8gbVjrxkZJd0FOYOuD4n3WSl4IVAV2HStrcAuVGvr4Of1wg8f/rhmxQaVPx/1o0sp+1jIOJpXxvijTziswE7a1adlh4K1sYKzJjsGx+02UAu0HlahP5wUeCbmcc/uhqL4Ocy6vP81TawvRv8wXDG0J+ZE76d9sdxn9mjkDQBllTnARMYtHKMpSLNkBLybgiToJeVDotMOHgnScUL1uLwXGQKNbW1mizFnOolamwlwlGk4p/bMfsEQ DhyfDdt9 MUSyRtGxNBKN9/eyyx80ztuYNcK53xedt95jMcB8ua0quyN4+KPQHztB4XgoDN6/3j11a912i2eR0SfvfYzEwKHNx/NMkEOspX0JgbtkU3mVOQ70y+g2wsxC1pCB0ztTWwTgbHwUaraiv7YIRVZh3nFx/CKV78oayaR0A2kWt+SUsjEpS/OUTTxNiL2WQyGMtPV3SQWKLOJPwTdxm1M5SAvMT45edwxxrXU6xF1sY4AcXDZMOjCFaWK6HTzb7WcrCiaBBIGGSp+dpcZx1aZJEWhhefw== 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: When I tested the mincore() syscall, I observed that it takes longer with 64K mTHP enabled on my Arm64 server. The reason is the mincore_pte_range() still checks each PTE individually, even when the PTEs are contiguous, which is not efficient. Thus we can use folio_pte_batch() to get the batch number of the present contiguous PTEs, which can improve the performance. I tested the mincore() syscall with 1G anonymous memory populated with 64K mTHP, and observed an obvious performance improvement: w/o patch w/ patch changes 6022us 1115us +81% Moreover, I also tested mincore() with disabling mTHP/THP, and did not see any obvious regression. Signed-off-by: Baolin Wang --- mm/mincore.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/mm/mincore.c b/mm/mincore.c index 832f29f46767..88be180b5550 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -21,6 +21,7 @@ #include #include "swap.h" +#include "internal.h" static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long end, struct mm_walk *walk) @@ -105,6 +106,7 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t *ptep; unsigned char *vec = walk->private; int nr = (end - addr) >> PAGE_SHIFT; + int step, i; ptl = pmd_trans_huge_lock(pmd, vma); if (ptl) { @@ -118,16 +120,31 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, walk->action = ACTION_AGAIN; return 0; } - for (; addr != end; ptep++, addr += PAGE_SIZE) { + for (; addr != end; ptep += step, addr += step * PAGE_SIZE) { pte_t pte = ptep_get(ptep); + step = 1; /* We need to do cache lookup too for pte markers */ if (pte_none_mostly(pte)) __mincore_unmapped_range(addr, addr + PAGE_SIZE, vma, vec); - else if (pte_present(pte)) - *vec = 1; - else { /* pte is a swap entry */ + else if (pte_present(pte)) { + if (pte_batch_hint(ptep, pte) > 1) { + struct folio *folio = vm_normal_folio(vma, addr, pte); + + if (folio && folio_test_large(folio)) { + const fpb_t fpb_flags = FPB_IGNORE_DIRTY | + FPB_IGNORE_SOFT_DIRTY; + int max_nr = (end - addr) / PAGE_SIZE; + + step = folio_pte_batch(folio, addr, ptep, pte, + max_nr, fpb_flags, NULL, NULL, NULL); + } + } + + for (i = 0; i < step; i++) + vec[i] = 1; + } else { /* pte is a swap entry */ swp_entry_t entry = pte_to_swp_entry(pte); if (non_swap_entry(entry)) { @@ -146,7 +163,7 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, #endif } } - vec++; + vec += step; } pte_unmap_unlock(ptep - 1, ptl); out: