- 03 11月, 2014 1 次提交
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由 Christoph Lameter 提交于
This still has not been merged and now powerpc is the only arch that does not have this change. Sorry about missing linuxppc-dev before. V2->V2 - Fix up to work against 3.18-rc1 __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Paul Mackerras <paulus@samba.org> Signed-off-by: NChristoph Lameter <cl@linux.com> [mpe: Fix build errors caused by set/or_softirq_pending(), and rework assignment in __set_breakpoint() to use memcpy().] Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 25 9月, 2014 1 次提交
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由 Zhouyi Zhou 提交于
CONFIG_JUMP_LABEL doesn't ensure HAVE_JUMP_LABEL, if it is not the case use maintainers's own mutex to guard the modification of global values. Signed-off-by: NZhouyi Zhou <yizhouzhou@ict.ac.cn> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 27 8月, 2014 2 次提交
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由 Tejun Heo 提交于
This reverts commit 5828f666 due to build failure after merging with pending powerpc changes. Link: http://lkml.kernel.org/g/20140827142243.6277eaff@canb.auug.org.auSigned-off-by: NTejun Heo <tj@kernel.org> Reported-by: NStephen Rothwell <sfr@canb.auug.org.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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由 Christoph Lameter 提交于
__get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) tj: Folded a fix patch. http://lkml.kernel.org/g/alpine.DEB.2.11.1408172143020.9652@gentwo.org Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Paul Mackerras <paulus@samba.org> Signed-off-by: NChristoph Lameter <cl@linux.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 11 7月, 2014 1 次提交
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由 Anton Blanchard 提交于
Knowing how long we spend in firmware calls is an important part of minimising OS jitter. This patch adds tracepoints to each OPAL call. If tracepoints are enabled we branch out to a common routine that calls an entry and exit tracepoint. This allows us to write tools that monitor the frequency and duration of OPAL calls, eg: name count total(ms) min(ms) max(ms) avg(ms) period(ms) OPAL_HANDLE_INTERRUPT 5 0.199 0.037 0.042 0.040 12547.545 OPAL_POLL_EVENTS 204 2.590 0.012 0.036 0.013 2264.899 OPAL_PCI_MSI_EOI 2830 3.066 0.001 0.005 0.001 81.166 We use jump labels if configured, which means we only add a single nop instruction to every OPAL call when the tracepoints are disabled. Signed-off-by: NAnton Blanchard <anton@samba.org> Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
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