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| author |   Dave Hansen <dave@sr71.net> | 2015-07-17 12:28:11 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2015-07-18 03:42:35 +0200 |
| commit | 0c8c0f03e3a292e031596484275c14cf39c0ab7a (patch) | |
| tree | c1d012c83722e9fa3b7bc152e64697828f6cbc35 /arch/x86/include/asm/processor.h | |
| parent | x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code (diff) | |
| download | linux-dev-0c8c0f03e3a292e031596484275c14cf39c0ab7a.tar.xz linux-dev-0c8c0f03e3a292e031596484275c14cf39c0ab7a.zip | |
x86/fpu, sched: Dynamically allocate 'struct fpu'
The FPU rewrite removed the dynamic allocations of 'struct fpu'.
But, this potentially wastes massive amounts of memory (2k per
task on systems that do not have AVX-512 for instance).
Instead of having a separate slab, this patch just appends the
space that we need to the 'task_struct' which we dynamically
allocate already. This saves from doing an extra slab
allocation at fork().
The only real downside here is that we have to stick everything
and the end of the task_struct. But, I think the
BUILD_BUG_ON()s I stuck in there should keep that from being too
fragile.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437128892-9831-2-git-send-email-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/processor.h')
| -rw-r--r-- | arch/x86/include/asm/processor.h | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 43e6519df0d5..944f1785ed0d 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -390,9 +390,6 @@ struct thread_struct { #endif unsigned long gs; - /* Floating point and extended processor state */ - struct fpu fpu; - /* Save middle states of ptrace breakpoints */ struct perf_event *ptrace_bps[HBP_NUM]; /* Debug status used for traps, single steps, etc... */ @@ -418,6 +415,13 @@ struct thread_struct { unsigned long iopl; /* Max allowed port in the bitmap, in bytes: */ unsigned io_bitmap_max; + + /* Floating point and extended processor state */ + struct fpu fpu; + /* + * WARNING: 'fpu' is dynamically-sized. It *MUST* be at + * the end. + */ }; /* |