From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F6E824B25E for ; Fri, 10 Jan 2025 22:15:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736547354; cv=none; b=rGednQ2jRBKH+7sBq1UDzJNSeaVSs2zE/5k0fc1D9bQ/aO4kXo52IGmGEMkCaLmcbbZouIOd6A3eQnmyfe3SWukkYcuLKWCeI0a681PTCcwhrGy4GTb1MnutQsPvJAAj4TqSwrWSfaulX66Z7H1zTzWB3oWNarxGoazqhbPWLuY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736547354; c=relaxed/simple; bh=gnlGkcqoy8HDXZ9a0ZC+/Ln+qP750ey1PbJxmMWBHiA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=aCVk2YNqusC3oeCu7mQVqlH6qNXViXY+KQYNtIdNZJWI35vTf2kJwRJln6mLDev5zT5W2xuYjzWz5QtlarAhJTZlWujcw0wETQi5yx7c5NTQzPWYTMau+NZ+brBvRpY/XGCz/TmU6p4WP/EpgJTksmdnCO3JBBCjNFySnmC36fg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=yc2W6Uhl; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="yc2W6Uhl" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2ef8c7ef51dso4568859a91.1 for ; Fri, 10 Jan 2025 14:15:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1736547352; x=1737152152; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WARCt/vdn+mdVM4SzGkFnsiJbS611IMJoZ0S5oBY9ZA=; b=yc2W6Uhl6pzurS2W/JKQmE/G0LxxQ4TYYSYraCyyv1JtXhbe/y6PzLTTqY4AbbLLR2 duo6HLjFOxVsJWsHmKy/ILGh7+x5bmrbPKJ1r3MooRpY6jL1QleAAtwhda3FppEI5eRj FiTcwi0UZv4OrxYQT3au15zJSGDxEsNlezRpNcuFI9SWVnE/qmpmNQDlvPWHbhapwf30 6B1sexpGhTYLoEpD/oN4thFJRxkCIorwcegmw74o62B2XT9pAXKOu2bmbiYG4o+pNmQ5 pKzwKe06Txtj92zZgLR2GMLvtUhiZN/HLWb8HmSuoPpSmGITjCJ6DzKIFAxm+iRU3iFV 3qrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1736547352; x=1737152152; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WARCt/vdn+mdVM4SzGkFnsiJbS611IMJoZ0S5oBY9ZA=; b=K7670mC8u06W8z0svjEzDlIT8iMD4vUsdE39CygLuZKf92TVNEGF1jPpatx5dAfxpj lJN0KgEbmsEjh3mmuxU0BEsp+yUaRjKysoJ6fViKSVZrRUizGCt+fEJsehQJSbZFkb5O uSUL0IT0vBumhy7CTpfPpBmqsszcs0o1JF3CHY131AiTNH+TOTSFEBUOZAc2DV1anu0+ qUDNCtd436mVrFiv7Wy9MkkO/ZUUPNXgaRKzJUiR5zOskX4qqJv0sy5U5MT/DSY6L/NZ fpVolU1tJy+EaBcFNBipMGQ+By8xYCyX1zz1p5Ff/Z8l6UqVlMRCbQxnMhxsrLbVdvxk Tnng== X-Forwarded-Encrypted: i=1; AJvYcCXjN1caeDAHywxRTNLzo4jcSb+6A8VDX9adVauvFY64f266nHttP1li4uErjEsjY2CMKJ4=@vger.kernel.org X-Gm-Message-State: AOJu0Yw74yyfz1TdF/mT3Q/PVN8S3KFknGlSBbK9xgFIR3+JuvIYkbtx rd3gOM5OcyPdN2UIjL45oql24mHBD5cI0wcIFNLBho8j5bU01VhFK76ZQhdAMPRbxHDdKMHuR7y XJg== X-Google-Smtp-Source: AGHT+IFMgbGPh/f2NFCJsUCfG4G1W6cH/dRD+d3e6//H3dc23WWf2uFuIbgG2SvY04H9rIGvR5K/Qf9mhR0= X-Received: from pjboh12.prod.google.com ([2002:a17:90b:3a4c:b0:2da:5868:311c]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3b4f:b0:2f2:a974:fc11 with SMTP id 98e67ed59e1d1-2f554603e39mr12751309a91.17.1736547352564; Fri, 10 Jan 2025 14:15:52 -0800 (PST) Date: Fri, 10 Jan 2025 14:15:51 -0800 In-Reply-To: <20241105184333.2305744-2-jthoughton@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241105184333.2305744-1-jthoughton@google.com> <20241105184333.2305744-2-jthoughton@google.com> Message-ID: Subject: Re: [PATCH v8 01/11] KVM: Remove kvm_handle_hva_range helper functions From: Sean Christopherson To: James Houghton Cc: Paolo Bonzini , David Matlack , David Rientjes , Marc Zyngier , Oliver Upton , Wei Xu , Yu Zhao , Axel Rasmussen , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Tue, Nov 05, 2024, James Houghton wrote: > kvm_handle_hva_range is only used by the young notifiers. In a later > patch, it will be even further tied to the young notifiers. Instead of > renaming kvm_handle_hva_range to something like When referencing functions, include parantheses so its super obvious that the symbol is a function(), e.g. kvm_handle_hva_range(), kvm_handle_hva_range_young(), etc. > kvm_handle_hva_range_young, simply remove kvm_handle_hva_range. This > seems slightly more readable, I disagree, quite strongly in fact. The amount of duplication makes it harder to see the differences between the three aging flow, and the fewer instances of this pattern: return kvm_handle_hva_range(kvm, &range).ret; the better. I added the tuple return as a way to avoid an out-param (which I still think is a good tradeoff), but there's definitely a cost to it. > though there is slightly more code duplication. Heh, you have a different definition of "slightly". The total lines of code may be close to a wash, but at the end of the series there's ~10 lines of code that is nearly identical in three different places. My vote is for this: --- virt/kvm/kvm_main.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index de2c11dae231..bf4670e9fcc6 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -551,8 +551,8 @@ static void kvm_null_fn(void) node; \ node = interval_tree_iter_next(node, start, last)) \ -static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, - const struct kvm_mmu_notifier_range *range) +static __always_inline kvm_mn_ret_t kvm_handle_hva_range(struct kvm *kvm, + const struct kvm_mmu_notifier_range *range) { struct kvm_mmu_notifier_return r = { .ret = false, @@ -628,7 +628,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, return r; } -static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, +static __always_inline int kvm_age_hva_range(struct mmu_notifier *mn, unsigned long start, unsigned long end, gfn_handler_t handler, @@ -647,10 +647,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn, return __kvm_handle_hva_range(kvm, &range).ret; } -static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn, - unsigned long start, - unsigned long end, - gfn_handler_t handler) +static __always_inline int kvm_age_hva_range_no_flush(struct mmu_notifier *mn, + unsigned long start, + unsigned long end, + gfn_handler_t handler) { return kvm_handle_hva_range(mn, start, end, handler, false); } @@ -747,7 +747,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, * that guest memory has been reclaimed. This needs to be done *after* * dropping mmu_lock, as x86's reclaim path is slooooow. */ - if (__kvm_handle_hva_range(kvm, &hva_range).found_memslot) + if (kvm_handle_hva_range(kvm, &hva_range).found_memslot) kvm_arch_guest_memory_reclaimed(kvm); return 0; @@ -793,7 +793,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, }; bool wake; - __kvm_handle_hva_range(kvm, &hva_range); + kvm_handle_hva_range(kvm, &hva_range); /* Pairs with the increment in range_start(). */ spin_lock(&kvm->mn_invalidate_lock); @@ -817,8 +817,8 @@ static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, { trace_kvm_age_hva(start, end); - return kvm_handle_hva_range(mn, start, end, kvm_age_gfn, - !IS_ENABLED(CONFIG_KVM_ELIDE_TLB_FLUSH_IF_YOUNG)); + return kvm_age_hva_range(mn, start, end, kvm_age_gfn, + !IS_ENABLED(CONFIG_KVM_ELIDE_TLB_FLUSH_IF_YOUNG)); } static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, @@ -841,7 +841,7 @@ static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, * cadence. If we find this inaccurate, we might come up with a * more sophisticated heuristic later. */ - return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn); + return kvm_age_hva_range_no_flush(mn, start, end, kvm_age_gfn); } static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn, @@ -850,8 +850,7 @@ static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn, { trace_kvm_test_age_hva(address); - return kvm_handle_hva_range_no_flush(mn, address, address + 1, - kvm_test_age_gfn); + return kvm_age_hva_range_no_flush(mn, address, address + 1, kvm_test_age_gfn); } static void kvm_mmu_notifier_release(struct mmu_notifier *mn, base-commit: 2d5faa6a8402435d6332e8e8f3c3f18cca382d83 --