| Message ID | 20190903052407.16638-7-alastair@au1.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc: convert cache asm to C | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | warning | Failed to apply on branch next (c317052c95bef1f977b023158e5aa929215f443d) |
| snowpatch_ozlabs/apply_patch | fail | Failed to apply to any branch |
Le 03/09/2019 à 07:24, Alastair D'Silva a écrit : > From: Alastair D'Silva <alastair@d-silva.org> > > This operation takes a significant amount of time when hotplugging > large amounts of memory (~50 seconds with 890GB of persistent memory). > > This was orignally in commit fb5924fddf9e > ("powerpc/mm: Flush cache on memory hot(un)plug") to support memtrace, > but the flush on add is not needed as it is flushed on remove. > > Signed-off-by: Alastair D'Silva <alastair@d-silva.org> > --- > arch/powerpc/mm/mem.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > index 854aaea2c6ae..2a14b5b93e19 100644 > --- a/arch/powerpc/mm/mem.c > +++ b/arch/powerpc/mm/mem.c > @@ -111,7 +111,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, > { > unsigned long start_pfn = start >> PAGE_SHIFT; > unsigned long nr_pages = size >> PAGE_SHIFT; > - u64 i; > int rc; > > resize_hpt_for_hotplug(memblock_phys_mem_size()); > @@ -124,12 +123,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, > return -EFAULT; > } > > - for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { > - flush_dcache_range(start + i, > - min(start + size, start + i + FLUSH_CHUNK_SIZE)); > - cond_resched(); > - } > - So you are removing the code you added in patch 4. Why not move this one before patch 4 ? > return __add_pages(nid, start_pfn, nr_pages, restrictions); > } > > Christophe
On Tue, 2019-09-03 at 08:23 +0200, Christophe Leroy wrote: > > Le 03/09/2019 à 07:24, Alastair D'Silva a écrit : > > From: Alastair D'Silva <alastair@d-silva.org> > > > > This operation takes a significant amount of time when hotplugging > > large amounts of memory (~50 seconds with 890GB of persistent > > memory). > > > > This was orignally in commit fb5924fddf9e > > ("powerpc/mm: Flush cache on memory hot(un)plug") to support > > memtrace, > > but the flush on add is not needed as it is flushed on remove. > > > > Signed-off-by: Alastair D'Silva <alastair@d-silva.org> > > --- > > arch/powerpc/mm/mem.c | 7 ------- > > 1 file changed, 7 deletions(-) > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index 854aaea2c6ae..2a14b5b93e19 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -111,7 +111,6 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > { > > unsigned long start_pfn = start >> PAGE_SHIFT; > > unsigned long nr_pages = size >> PAGE_SHIFT; > > - u64 i; > > int rc; > > > > resize_hpt_for_hotplug(memblock_phys_mem_size()); > > @@ -124,12 +123,6 @@ int __ref arch_add_memory(int nid, u64 start, > > u64 size, > > return -EFAULT; > > } > > > > - for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { > > - flush_dcache_range(start + i, > > - min(start + size, start + i + > > FLUSH_CHUNK_SIZE)); > > - cond_resched(); > > - } > > - > > So you are removing the code you added in patch 4. Why not move this > one > before patch 4 ? > I put them in this order so that if someone did want the flushes in arch_add_memory, they could drop the later patch, but not trigger RCU stalls.
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 854aaea2c6ae..2a14b5b93e19 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -111,7 +111,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, { unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; - u64 i; int rc; resize_hpt_for_hotplug(memblock_phys_mem_size()); @@ -124,12 +123,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, return -EFAULT; } - for (i = 0; i < size; i += FLUSH_CHUNK_SIZE) { - flush_dcache_range(start + i, - min(start + size, start + i + FLUSH_CHUNK_SIZE)); - cond_resched(); - } - return __add_pages(nid, start_pfn, nr_pages, restrictions); }