From: Linus Torvalds <torvalds@linux-foundation.org>
To: Michael Neuling <mikey@neuling.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
benh@kernel.crashing.org, anton@samba.org
Subject: Re: [PATCH 0/2] More i387 state save/restore work
Date: Sun, 19 Feb 2012 17:11:12 -0800 [thread overview]
Message-ID: <CA+55aFwc6u6Mr9iCMKM+MexfKso4tN7D2VdWpJpuT2saj0Pgfw@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFxqK1A0g6qHvZHxzGOTGT0YFAoRJtOeYWLxVchM=e=qww@mail.gmail.com>
Oh, and final comment - looking at the thing you pointed at, it looks
much more adventurous than my x86 FP state thing.
I always save things unconditionally, so that I don't have to do the
IPI or just in general care about the "oops, now I want things in
memory, not in some random CPU FP state". So mine is just a "writeback
cache", and only optimizes the reading things back: there is never any
dirty state in the CPU except when the process is actively using it.
That obviously does mean that I only optimize away the restore side,
not the save side. But it's *way* simpler, and considering that I just
spent almost a week trying to figure out FP state save bugs, simple is
good.
Linus
next prev parent reply other threads:[~2012-02-20 1:11 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-19 22:23 [PATCH 0/2] More i387 state save/restore work Linus Torvalds
2012-02-19 22:26 ` [PATCH 1/2] i387: use 'restore_fpu_checking()' directly in task switching code Linus Torvalds
2012-02-19 22:37 ` [PATCH 2/2] i387: support lazy restore of FPU state Linus Torvalds
2012-02-19 22:44 ` H. Peter Anvin
2012-02-19 23:18 ` H. Peter Anvin
2012-02-19 23:56 ` Linus Torvalds
2012-02-20 7:51 ` Ingo Molnar
2012-02-20 0:53 ` [PATCH 0/2] More i387 state save/restore work Michael Neuling
2012-02-20 1:03 ` Linus Torvalds
2012-02-20 1:06 ` Linus Torvalds
2012-02-20 1:11 ` Linus Torvalds [this message]
2012-03-01 11:30 ` Benjamin Herrenschmidt
2012-02-20 2:09 ` Indan Zupancic
2012-02-20 19:46 ` [PATCH v2 0/3] " Linus Torvalds
2012-02-20 19:47 ` [PATCH v2 1/3] i387: fix up some fpu_counter confusion Linus Torvalds
2012-02-20 19:48 ` [PATCH v2 2/3] i387: use 'restore_fpu_checking()' directly in task switching code Linus Torvalds
2012-02-20 19:48 ` [PATCH v2 3/3] i387: support lazy restore of FPU state Linus Torvalds
2012-02-21 1:50 ` Josh Boyer
2012-02-21 2:10 ` Linus Torvalds
2012-02-21 2:14 ` H. Peter Anvin
2012-02-21 5:27 ` Linus Torvalds
2012-02-21 5:35 ` H. Peter Anvin
2012-02-21 14:19 ` Josh Boyer
2012-02-21 17:59 ` H. Peter Anvin
2012-02-21 18:06 ` Ingo Molnar
2012-02-21 18:26 ` Linus Torvalds
2012-02-21 21:14 ` H. Peter Anvin
2012-02-21 21:39 ` [PATCH 0/2] i387: FP state interface cleanups Linus Torvalds
2012-02-21 21:40 ` [PATCH 1/2] i387: uninline the generic FP helpers that we expose to kernel modules Linus Torvalds
2012-02-21 21:41 ` [PATCH 2/2] i387: split up <asm/i387.h> into exported and internal interfaces Linus Torvalds
2012-02-21 23:50 ` [tip:x86/fpu] i387: Split " tip-bot for Linus Torvalds
2012-02-28 11:21 ` [PATCH 2/2] i387: split " Avi Kivity
2012-02-28 16:05 ` Linus Torvalds
2012-02-28 17:21 ` Avi Kivity
2012-02-28 17:37 ` Linus Torvalds
2012-02-28 18:08 ` Linus Torvalds
2012-02-28 18:29 ` Avi Kivity
2012-02-28 18:09 ` Avi Kivity
2012-02-28 18:34 ` Linus Torvalds
2012-02-28 19:06 ` Avi Kivity
2012-02-28 19:26 ` Linus Torvalds
2012-02-28 19:45 ` Avi Kivity
2012-02-21 23:49 ` [tip:x86/fpu] i387: Uninline the generic FP helpers that we expose to kernel modules tip-bot for Linus Torvalds
2012-02-21 2:18 ` [PATCH v2 3/3] i387: support lazy restore of FPU state Linus Torvalds
2012-02-21 2:32 ` H. Peter Anvin
2012-02-21 2:11 ` H. Peter Anvin
2012-02-21 21:54 ` Suresh Siddha
2012-02-21 21:57 ` Linus Torvalds
2012-02-21 22:19 ` Suresh Siddha
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