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[92.145.124.62]) by smtp.gmail.com with ESMTPSA id l27-20020a05600c1d1b00b003fe1b3e0852sm2908793wms.0.2023.08.01.01.57.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 01:57:09 -0700 (PDT) From: Alexandre Ghiti To: Will Deacon , "Aneesh Kumar K . V" , Andrew Morton , Nick Piggin , Peter Zijlstra , Mayuresh Chitale , Vincent Chen , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alexandre Ghiti , Andrew Jones Subject: [PATCH v3 3/4] riscv: Make __flush_tlb_range() loop over pte instead of flushing the whole tlb Date: Tue, 1 Aug 2023 10:54:01 +0200 Message-Id: <20230801085402.1168351-4-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230801085402.1168351-1-alexghiti@rivosinc.com> References: <20230801085402.1168351-1-alexghiti@rivosinc.com> MIME-Version: 1.0 X-Stat-Signature: b7skkqhzbrskishz8a71exgcgna8ch3e X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 745EA40018 X-Rspam-User: X-HE-Tag: 1690880231-488944 X-HE-Meta: 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 05TYBh8v 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 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: Currently, when the range to flush covers more than one page (a 4K page or a hugepage), __flush_tlb_range() flushes the whole tlb. Flushing the whole tlb comes with a greater cost than flushing a single entry so we should flush single entries up to a certain threshold so that: threshold * cost of flushing a single entry < cost of flushing the whole tlb. Co-developed-by: Mayuresh Chitale Signed-off-by: Mayuresh Chitale Signed-off-by: Alexandre Ghiti Reviewed-by: Andrew Jones --- arch/riscv/mm/tlbflush.c | 48 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 44 insertions(+), 4 deletions(-) diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c index d883df0dee4a..0c955c474f3a 100644 --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -7,6 +7,9 @@ #include #include +#define FLUSH_TLB_MAX_SIZE ((unsigned long)-1) +#define FLUSH_TLB_NO_ASID ((unsigned long)-1) + static inline void local_flush_tlb_all_asid(unsigned long asid) { __asm__ __volatile__ ("sfence.vma x0, %0" @@ -24,13 +27,48 @@ static inline void local_flush_tlb_page_asid(unsigned long addr, : "memory"); } +/* + * Flush entire TLB if number of entries to be flushed is greater + * than the threshold below. + */ +static unsigned long tlb_flush_all_threshold __read_mostly = 64; + +static void local_flush_tlb_range_threshold_asid(unsigned long start, + unsigned long size, + unsigned long stride, + unsigned long asid) +{ + u16 nr_ptes_in_range = DIV_ROUND_UP(size, stride); + int i; + + if (nr_ptes_in_range > tlb_flush_all_threshold) { + if (asid != FLUSH_TLB_NO_ASID) + local_flush_tlb_all_asid(asid); + else + local_flush_tlb_all(); + return; + } + + for (i = 0; i < nr_ptes_in_range; ++i) { + if (asid != FLUSH_TLB_NO_ASID) + local_flush_tlb_page_asid(start, asid); + else + local_flush_tlb_page(start); + start += stride; + } +} + static inline void local_flush_tlb_range(unsigned long start, unsigned long size, unsigned long stride) { if (size <= stride) local_flush_tlb_page(start); - else + else if (size == FLUSH_TLB_MAX_SIZE) local_flush_tlb_all(); + else + local_flush_tlb_range_threshold_asid(start, size, stride, + FLUSH_TLB_NO_ASID); + } static inline void local_flush_tlb_range_asid(unsigned long start, @@ -38,8 +76,10 @@ static inline void local_flush_tlb_range_asid(unsigned long start, { if (size <= stride) local_flush_tlb_page_asid(start, asid); - else + else if (size == FLUSH_TLB_MAX_SIZE) local_flush_tlb_all_asid(asid); + else + local_flush_tlb_range_threshold_asid(start, size, stride, asid); } static void __ipi_flush_tlb_all(void *info) @@ -52,7 +92,7 @@ void flush_tlb_all(void) if (riscv_use_ipi_for_rfence()) on_each_cpu(__ipi_flush_tlb_all, NULL, 1); else - sbi_remote_sfence_vma(NULL, 0, -1); + sbi_remote_sfence_vma(NULL, 0, FLUSH_TLB_MAX_SIZE); } struct flush_tlb_range_data { @@ -130,7 +170,7 @@ static void __flush_tlb_range(struct mm_struct *mm, unsigned long start, void flush_tlb_mm(struct mm_struct *mm) { - __flush_tlb_range(mm, 0, -1, PAGE_SIZE); + __flush_tlb_range(mm, 0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE); } void flush_tlb_mm_range(struct mm_struct *mm,