| Message ID | 20230721131800.20003-3-bhe@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | percpu: some trivial cleanup patches | expand |
Hello, On Fri, Jul 21, 2023 at 09:17:59PM +0800, Baoquan He wrote: > This removes the need of local varibale 'chunk', and optimize the code > calling pcpu_alloc_first_chunk() to initialize reserved chunk and > dynamic chunk to make it simpler. > > Signed-off-by: Baoquan He <bhe@redhat.com> > --- > mm/percpu.c | 32 +++++++++++++------------------- > 1 file changed, 13 insertions(+), 19 deletions(-) > > diff --git a/mm/percpu.c b/mm/percpu.c > index 1480bf283d11..c25b058a46ad 100644 > --- a/mm/percpu.c > +++ b/mm/percpu.c > @@ -2581,7 +2581,6 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > { > size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; > size_t static_size, dyn_size; > - struct pcpu_chunk *chunk; > unsigned long *group_offsets; > size_t *group_sizes; > unsigned long *unit_off; > @@ -2697,7 +2696,7 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; > pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; > pcpu_atom_size = ai->atom_size; > - pcpu_chunk_struct_size = struct_size(chunk, populated, > + pcpu_chunk_struct_size = struct_size((struct pcpu_chunk *)0, populated, > BITS_TO_LONGS(pcpu_unit_pages)); > > pcpu_stats_save_ai(ai); > @@ -2735,28 +2734,23 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > > /* > * Initialize first chunk. > - * If the reserved_size is non-zero, this initializes the reserved > - * chunk. If the reserved_size is zero, the reserved chunk is NULL > - * and the dynamic region is initialized here. The first chunk, > - * pcpu_first_chunk, will always point to the chunk that serves > - * the dynamic region. > + * If the reserved_size is non-zero, initializes the reserved chunk ^initialize > + * firstly. If the reserved_size is zero, the reserved chunk is NULL ^ can remove firstly. > + * and the dynamic region is initialized directly. The first chunk, > + * pcpu_first_chunk, will always point to the chunk that serves the > + * dynamic region. Reading this, I'll probably reword this comment to explain the reserved chunk better. > */ > tmp_addr = (unsigned long)base_addr + static_size; > - map_size = ai->reserved_size ?: dyn_size; > - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > - > - /* init dynamic chunk if necessary */ > if (ai->reserved_size) { > - pcpu_reserved_chunk = chunk; > - > - tmp_addr = (unsigned long)base_addr + static_size + > - ai->reserved_size; > - map_size = dyn_size; > - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > + map_size = ai->reserved_size; > + pcpu_reserved_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > } > > - /* link the first chunk in */ > - pcpu_first_chunk = chunk; > + /* init dynamic chunk if necessary */ > + tmp_addr += (unsigned long)ai->reserved_size; I'm not a big fan of += the tmp_addr as I personally find it easier to read if it's just laid out explicitly. > + map_size = dyn_size; > + pcpu_first_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > + > pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; > pcpu_chunk_relocate(pcpu_first_chunk, -1); > > -- > 2.34.1 > Overall, I think this is good, but I'd go 1 step further and get rid of map_size. Regarding tmp_addr, I'd prefer if we kept all the math together. Thanks, Dennis
On 07/21/23 at 02:01pm, Dennis Zhou wrote: > Hello, > > On Fri, Jul 21, 2023 at 09:17:59PM +0800, Baoquan He wrote: > > This removes the need of local varibale 'chunk', and optimize the code > > calling pcpu_alloc_first_chunk() to initialize reserved chunk and > > dynamic chunk to make it simpler. > > > > Signed-off-by: Baoquan He <bhe@redhat.com> > > --- > > mm/percpu.c | 32 +++++++++++++------------------- > > 1 file changed, 13 insertions(+), 19 deletions(-) > > > > diff --git a/mm/percpu.c b/mm/percpu.c > > index 1480bf283d11..c25b058a46ad 100644 > > --- a/mm/percpu.c > > +++ b/mm/percpu.c > > @@ -2581,7 +2581,6 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > > { > > size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; > > size_t static_size, dyn_size; > > - struct pcpu_chunk *chunk; > > unsigned long *group_offsets; > > size_t *group_sizes; > > unsigned long *unit_off; > > @@ -2697,7 +2696,7 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > > pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; > > pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; > > pcpu_atom_size = ai->atom_size; > > - pcpu_chunk_struct_size = struct_size(chunk, populated, > > + pcpu_chunk_struct_size = struct_size((struct pcpu_chunk *)0, populated, > > BITS_TO_LONGS(pcpu_unit_pages)); > > > > pcpu_stats_save_ai(ai); > > @@ -2735,28 +2734,23 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, > > > > /* > > * Initialize first chunk. > > - * If the reserved_size is non-zero, this initializes the reserved > > - * chunk. If the reserved_size is zero, the reserved chunk is NULL > > - * and the dynamic region is initialized here. The first chunk, > > - * pcpu_first_chunk, will always point to the chunk that serves > > - * the dynamic region. > > + * If the reserved_size is non-zero, initializes the reserved chunk > ^initialize > > + * firstly. If the reserved_size is zero, the reserved chunk is NULL > ^ can remove firstly. > > + * and the dynamic region is initialized directly. The first chunk, > > + * pcpu_first_chunk, will always point to the chunk that serves the > > + * dynamic region. > > Reading this, I'll probably reword this comment to explain the reserved > chunk better. Agree. The expression is a little messy and too colloquial. > > > */ > > tmp_addr = (unsigned long)base_addr + static_size; > > - map_size = ai->reserved_size ?: dyn_size; > > - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > > - > > - /* init dynamic chunk if necessary */ > > if (ai->reserved_size) { > > - pcpu_reserved_chunk = chunk; > > - > > - tmp_addr = (unsigned long)base_addr + static_size + > > - ai->reserved_size; > > - map_size = dyn_size; > > - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > > + map_size = ai->reserved_size; > > + pcpu_reserved_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > > } > > > > - /* link the first chunk in */ > > - pcpu_first_chunk = chunk; > > + /* init dynamic chunk if necessary */ > > + tmp_addr += (unsigned long)ai->reserved_size; > > I'm not a big fan of += the tmp_addr as I personally find it easier to > read if it's just laid out explicitly. OK, will change. > > > + map_size = dyn_size; > > + pcpu_first_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); > > + > > pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; > > pcpu_chunk_relocate(pcpu_first_chunk, -1); > > > > -- > > 2.34.1 > > > > Overall, I think this is good, but I'd go 1 step further and get rid of > map_size. Regarding tmp_addr, I'd prefer if we kept all the math > together. Makes sense. Thanks a lot for your careful review and great suggestions. According to your comments, I made a draft v2. Please help check if I have got them correctly and if the new change is OK to you. From 17832ce8a755d8327b853a18c6f1cc00c9f93e50 Mon Sep 17 00:00:00 2001 From: Baoquan He <bhe@redhat.com> Date: Tue, 27 Jun 2023 09:33:28 +0800 Subject: [PATCH] mm/percpu.c: optimize the code in pcpu_setup_first_chunk() a little bit Content-type: text/plain This removes the need of local varibale 'chunk', and optimize the code calling pcpu_alloc_first_chunk() to initialize reserved chunk and dynamic chunk to make it simpler. Signed-off-by: Baoquan He <bhe@redhat.com> --- mm/percpu.c | 36 +++++++++++++----------------------- 1 file changed, 13 insertions(+), 23 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index 1480bf283d11..83fc47206680 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -2581,14 +2581,12 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, { size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; size_t static_size, dyn_size; - struct pcpu_chunk *chunk; unsigned long *group_offsets; size_t *group_sizes; unsigned long *unit_off; unsigned int cpu; int *unit_map; int group, unit, i; - int map_size; unsigned long tmp_addr; size_t alloc_size; @@ -2697,7 +2695,7 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; pcpu_atom_size = ai->atom_size; - pcpu_chunk_struct_size = struct_size(chunk, populated, + pcpu_chunk_struct_size = struct_size((struct pcpu_chunk *)0, populated, BITS_TO_LONGS(pcpu_unit_pages)); pcpu_stats_save_ai(ai); @@ -2734,29 +2732,21 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, dyn_size = ai->dyn_size - (static_size - ai->static_size); /* - * Initialize first chunk. - * If the reserved_size is non-zero, this initializes the reserved - * chunk. If the reserved_size is zero, the reserved chunk is NULL - * and the dynamic region is initialized here. The first chunk, - * pcpu_first_chunk, will always point to the chunk that serves - * the dynamic region. + * Initialize first chunk: + * + * - If the reserved_size is non-zero, initialize the reserved + * chunk firstly. Otherwise, the reserved chunk is NULL. + * + * - The first chunk, pcpu_first_chunk, always points to the + * chunk that serves the dynamic region. */ tmp_addr = (unsigned long)base_addr + static_size; - map_size = ai->reserved_size ?: dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); - - /* init dynamic chunk if necessary */ - if (ai->reserved_size) { - pcpu_reserved_chunk = chunk; - - tmp_addr = (unsigned long)base_addr + static_size + - ai->reserved_size; - map_size = dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); - } + if (ai->reserved_size) + pcpu_reserved_chunk = pcpu_alloc_first_chunk(tmp_addr, + ai->reserved_size); + tmp_addr = (unsigned long)base_addr + static_size + ai->reserved_size; + pcpu_first_chunk = pcpu_alloc_first_chunk(tmp_addr, dyn_size); - /* link the first chunk in */ - pcpu_first_chunk = chunk; pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; pcpu_chunk_relocate(pcpu_first_chunk, -1);
diff --git a/mm/percpu.c b/mm/percpu.c index 1480bf283d11..c25b058a46ad 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -2581,7 +2581,6 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, { size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; size_t static_size, dyn_size; - struct pcpu_chunk *chunk; unsigned long *group_offsets; size_t *group_sizes; unsigned long *unit_off; @@ -2697,7 +2696,7 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT; pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT; pcpu_atom_size = ai->atom_size; - pcpu_chunk_struct_size = struct_size(chunk, populated, + pcpu_chunk_struct_size = struct_size((struct pcpu_chunk *)0, populated, BITS_TO_LONGS(pcpu_unit_pages)); pcpu_stats_save_ai(ai); @@ -2735,28 +2734,23 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, /* * Initialize first chunk. - * If the reserved_size is non-zero, this initializes the reserved - * chunk. If the reserved_size is zero, the reserved chunk is NULL - * and the dynamic region is initialized here. The first chunk, - * pcpu_first_chunk, will always point to the chunk that serves - * the dynamic region. + * If the reserved_size is non-zero, initializes the reserved chunk + * firstly. If the reserved_size is zero, the reserved chunk is NULL + * and the dynamic region is initialized directly. The first chunk, + * pcpu_first_chunk, will always point to the chunk that serves the + * dynamic region. */ tmp_addr = (unsigned long)base_addr + static_size; - map_size = ai->reserved_size ?: dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); - - /* init dynamic chunk if necessary */ if (ai->reserved_size) { - pcpu_reserved_chunk = chunk; - - tmp_addr = (unsigned long)base_addr + static_size + - ai->reserved_size; - map_size = dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); + map_size = ai->reserved_size; + pcpu_reserved_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); } - /* link the first chunk in */ - pcpu_first_chunk = chunk; + /* init dynamic chunk if necessary */ + tmp_addr += (unsigned long)ai->reserved_size; + map_size = dyn_size; + pcpu_first_chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); + pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; pcpu_chunk_relocate(pcpu_first_chunk, -1);
This removes the need of local varibale 'chunk', and optimize the code calling pcpu_alloc_first_chunk() to initialize reserved chunk and dynamic chunk to make it simpler. Signed-off-by: Baoquan He <bhe@redhat.com> --- mm/percpu.c | 32 +++++++++++++------------------- 1 file changed, 13 insertions(+), 19 deletions(-)