From: Borislav Petkov <bp@alien8.de>
To: Balbir Singh <sblbir@amazon.com>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
tony.luck@intel.com, keescook@chromium.org, x86@kernel.org,
benh@kernel.crashing.org, dave.hansen@intel.com
Subject: Re: [PATCH 3/3] arch/x86: Optionally flush L1D on context switch
Date: Fri, 3 Apr 2020 00:11:09 +0200 [thread overview]
Message-ID: <20200402221109.GJ9352@zn.tnic> (raw)
In-Reply-To: <20200402062401.29856-4-sblbir@amazon.com>
On Thu, Apr 02, 2020 at 05:24:01PM +1100, Balbir Singh wrote:
> +int enable_l1d_flush_for_task(struct task_struct *tsk)
> +{
> + struct page *page;
> + int ret = 0;
> +
> + if (static_cpu_has(X86_FEATURE_FLUSH_L1D))
> + goto done;
> +
> + page = READ_ONCE(l1d_flush_pages);
> + if (unlikely(!page)) {
> + mutex_lock(&l1d_flush_mutex);
> + if (!l1d_flush_pages) {
> + l1d_flush_pages = alloc_l1d_flush_pages();
> + if (!l1d_flush_pages)
> + return -ENOMEM;
Do I see it correctly that you'll return here with l1d_flush_mutex still
held?
> + }
> + mutex_unlock(&l1d_flush_mutex);
> + }
> + /* I don't think we need to worry about KSM */
Pls use passive voice: no "we" or "I", etc.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-04-02 22:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 6:23 [PATCH 0/3] arch/x86: Optionally flush L1D on context switch Balbir Singh
2020-04-02 6:23 ` [PATCH 1/3] arch/x86/kvm: Refactor l1d flush lifecycle management Balbir Singh
2020-04-02 6:24 ` [PATCH 2/3] arch/x86: Refactor tlbflush and l1d flush Balbir Singh
2020-04-02 6:24 ` [PATCH 3/3] arch/x86: Optionally flush L1D on context switch Balbir Singh
2020-04-02 22:11 ` Borislav Petkov [this message]
2020-04-02 22:18 ` Singh, Balbir
2020-04-02 20:13 ` [PATCH 0/3] " Josh Poimboeuf
2020-04-02 20:35 ` Singh, Balbir
2020-04-02 20:47 ` Josh Poimboeuf
2020-04-02 21:45 ` Thomas Gleixner
2020-04-02 22:23 ` Singh, Balbir
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