| Message ID | 20201111055524.2458-1-jniethe5@gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | powerpc/powernv/memtrace: Fake non-memblock aligned sized traces | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (80ecbe16c827714ce3741ed1f1d34488b903e717) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 46 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
CC Rashmica Gupta <rashmicy@gmail.com> On Wed, 2020-11-11 at 16:55 +1100, Jordan Niethe wrote: > The hardware trace macros which use the memory provided by memtrace are > able to use trace sizes as small as 16MB. Only memblock aligned values > can be removed from each NUMA node by writing that value to > memtrace/enable in debugfs. This means setting up, say, a 16MB trace is > not possible. To allow such a trace size, instead align whatever value > is written to memtrace/enable to the memblock size for the purpose of > removing it from each NUMA node but report the written value from > memtrace/enable and memtrace/x/size in debugfs. > > Signed-off-by: Jordan Niethe <jniethe5@gmail.com> > --- > arch/powerpc/platforms/powernv/memtrace.c | 20 ++++++-------------- > 1 file changed, 6 insertions(+), 14 deletions(-) > > diff --git a/arch/powerpc/platforms/powernv/memtrace.c > b/arch/powerpc/platforms/powernv/memtrace.c > index 6828108486f8..1188bc8fd090 100644 > --- a/arch/powerpc/platforms/powernv/memtrace.c > +++ b/arch/powerpc/platforms/powernv/memtrace.c > @@ -191,7 +191,7 @@ static int memtrace_init_debugfs(void) > ent->dir = dir; > debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); > debugfs_create_x64("start", 0400, dir, &ent->start); > - debugfs_create_x64("size", 0400, dir, &ent->size); > + debugfs_create_x64("size", 0400, dir, &memtrace_size); > } > > return ret; > @@ -259,33 +259,25 @@ static int memtrace_enable_set(void *data, u64 val) > { > u64 bytes; > > - /* > - * Don't attempt to do anything if size isn't aligned to a memory > - * block or equal to zero. > - */ > - bytes = memory_block_size_bytes(); > - if (val & (bytes - 1)) { > - pr_err("Value must be aligned with 0x%llx\n", bytes); > - return -EINVAL; > - } > - > /* Re-add/online previously removed/offlined memory */ > if (memtrace_size) { > if (memtrace_online()) > return -EAGAIN; > } > > + memtrace_size = val; > + > if (!val) > return 0; > > - /* Offline and remove memory */ > - if (memtrace_init_regions_runtime(val)) > + /* Offline and remove memory aligned to memory blocks */ > + bytes = memory_block_size_bytes(); > + if (memtrace_init_regions_runtime(ALIGN(val, bytes))) > return -EINVAL; > > if (memtrace_init_debugfs()) > return -EINVAL; > > - memtrace_size = val; > > return 0; > }
Jordan Niethe <jniethe5@gmail.com> writes: > The hardware trace macros which use the memory provided by memtrace are > able to use trace sizes as small as 16MB. Only memblock aligned values > can be removed from each NUMA node by writing that value to > memtrace/enable in debugfs. This means setting up, say, a 16MB trace is > not possible. To allow such a trace size, instead align whatever value > is written to memtrace/enable to the memblock size for the purpose of > removing it from each NUMA node but report the written value from > memtrace/enable and memtrace/x/size in debugfs. Why does it matter if the size that's removed is larger than the size that was requested? Is it about constraining the size of the trace? If so that seems like it should be the job of the tracing tools, not the kernel. cheers
On Mon, Nov 16, 2020 at 11:02 PM Michael Ellerman <mpe@ellerman.id.au> wrote: > > Jordan Niethe <jniethe5@gmail.com> writes: > > The hardware trace macros which use the memory provided by memtrace are > > able to use trace sizes as small as 16MB. Only memblock aligned values > > can be removed from each NUMA node by writing that value to > > memtrace/enable in debugfs. This means setting up, say, a 16MB trace is > > not possible. To allow such a trace size, instead align whatever value > > is written to memtrace/enable to the memblock size for the purpose of > > removing it from each NUMA node but report the written value from > > memtrace/enable and memtrace/x/size in debugfs. > > Why does it matter if the size that's removed is larger than the size > that was requested? > > Is it about constraining the size of the trace? If so that seems like it > should be the job of the tracing tools, not the kernel. Yeah about constraining the size, I'll just do it in the trace tools. > > cheers
Jordan Niethe <jniethe5@gmail.com> writes: > On Mon, Nov 16, 2020 at 11:02 PM Michael Ellerman <mpe@ellerman.id.au> wrote: >> >> Jordan Niethe <jniethe5@gmail.com> writes: >> > The hardware trace macros which use the memory provided by memtrace are >> > able to use trace sizes as small as 16MB. Only memblock aligned values >> > can be removed from each NUMA node by writing that value to >> > memtrace/enable in debugfs. This means setting up, say, a 16MB trace is >> > not possible. To allow such a trace size, instead align whatever value >> > is written to memtrace/enable to the memblock size for the purpose of >> > removing it from each NUMA node but report the written value from >> > memtrace/enable and memtrace/x/size in debugfs. >> >> Why does it matter if the size that's removed is larger than the size >> that was requested? >> >> Is it about constraining the size of the trace? If so that seems like it >> should be the job of the tracing tools, not the kernel. > > Yeah about constraining the size, I'll just do it in the trace tools. OK, I think that would be better. Thanks. cheers
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c index 6828108486f8..1188bc8fd090 100644 --- a/arch/powerpc/platforms/powernv/memtrace.c +++ b/arch/powerpc/platforms/powernv/memtrace.c @@ -191,7 +191,7 @@ static int memtrace_init_debugfs(void) ent->dir = dir; debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); debugfs_create_x64("start", 0400, dir, &ent->start); - debugfs_create_x64("size", 0400, dir, &ent->size); + debugfs_create_x64("size", 0400, dir, &memtrace_size); } return ret; @@ -259,33 +259,25 @@ static int memtrace_enable_set(void *data, u64 val) { u64 bytes; - /* - * Don't attempt to do anything if size isn't aligned to a memory - * block or equal to zero. - */ - bytes = memory_block_size_bytes(); - if (val & (bytes - 1)) { - pr_err("Value must be aligned with 0x%llx\n", bytes); - return -EINVAL; - } - /* Re-add/online previously removed/offlined memory */ if (memtrace_size) { if (memtrace_online()) return -EAGAIN; } + memtrace_size = val; + if (!val) return 0; - /* Offline and remove memory */ - if (memtrace_init_regions_runtime(val)) + /* Offline and remove memory aligned to memory blocks */ + bytes = memory_block_size_bytes(); + if (memtrace_init_regions_runtime(ALIGN(val, bytes))) return -EINVAL; if (memtrace_init_debugfs()) return -EINVAL; - memtrace_size = val; return 0; }
The hardware trace macros which use the memory provided by memtrace are able to use trace sizes as small as 16MB. Only memblock aligned values can be removed from each NUMA node by writing that value to memtrace/enable in debugfs. This means setting up, say, a 16MB trace is not possible. To allow such a trace size, instead align whatever value is written to memtrace/enable to the memblock size for the purpose of removing it from each NUMA node but report the written value from memtrace/enable and memtrace/x/size in debugfs. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> --- arch/powerpc/platforms/powernv/memtrace.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-)