| Message ID | 20220405135758.774016-9-catalin.marinas@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, arm64: Reduce ARCH_KMALLOC_MINALIGN below the cache line size | expand |
On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > ARCH_KMALLOC_MINALIGN represents the minimum guaranteed kmalloc() > alignment but an architecture may require a larger run-time alignment. > Do not create kmalloc caches smaller than arch_kmalloc_minalign(). > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > --- > include/linux/slab.h | 2 ++ > mm/slab.c | 6 +----- > mm/slab.h | 2 ++ > mm/slab_common.c | 33 +++++++++++++++++++++++---------- > 4 files changed, 28 insertions(+), 15 deletions(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index d58211bdeceb..2137dba85691 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -332,6 +332,8 @@ enum kmalloc_cache_type { > extern struct kmem_cache * > kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1]; > > +unsigned int arch_kmalloc_minalign(void); > + > /* > * Define gfp bits that should not be set for KMALLOC_NORMAL. > */ > diff --git a/mm/slab.c b/mm/slab.c > index b04e40078bdf..4aaeeb9c994d 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -1256,11 +1256,7 @@ void __init kmem_cache_init(void) > * Initialize the caches that provide memory for the kmem_cache_node > * structures first. Without this, further allocations will bug. > */ > - kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache( > - kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL], > - kmalloc_info[INDEX_NODE].size, > - ARCH_KMALLOC_FLAGS, 0, > - kmalloc_info[INDEX_NODE].size); > + new_kmalloc_cache(INDEX_NODE, KMALLOC_NORMAL, ARCH_KMALLOC_FLAGS); > slab_state = PARTIAL_NODE; > setup_kmalloc_cache_index_table(); > > diff --git a/mm/slab.h b/mm/slab.h > index fd7ae2024897..e9238406602a 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -283,6 +283,8 @@ int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); > struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size, > slab_flags_t flags, unsigned int useroffset, > unsigned int usersize); > +void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, > + slab_flags_t flags); > extern void create_boot_cache(struct kmem_cache *, const char *name, > unsigned int size, slab_flags_t flags, > unsigned int useroffset, unsigned int usersize); > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 6ee64d6208b3..594d8a8a68d0 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > } > } > > -static void __init > +unsigned int __weak arch_kmalloc_minalign(void) > +{ > + return ARCH_KMALLOC_MINALIGN; > +} > + As ARCH_KMALLOC_ALIGN and arch_kmalloc_minalign() may not be same after patch 10, I think s/ARCH_KMALLOC_ALIGN/arch_kmalloc_minalign/g for every user of it would be more correct? > +void __init > new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > { > + unsigned int minalign = arch_kmalloc_minalign(); > + unsigned int aligned_size = kmalloc_info[idx].size; > + int aligned_idx = idx; > + > if (type == KMALLOC_RECLAIM) { > flags |= SLAB_RECLAIM_ACCOUNT; > } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { > @@ -851,10 +860,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > flags |= SLAB_ACCOUNT; > } > > - kmalloc_caches[type][idx] = create_kmalloc_cache( > - kmalloc_info[idx].name[type], > - kmalloc_info[idx].size, flags, 0, > - kmalloc_info[idx].size); > + if (minalign > ARCH_KMALLOC_MINALIGN) { > + aligned_size = ALIGN(aligned_size, minalign); > + aligned_idx = __kmalloc_index(aligned_size, false); > + } > + > + if (!kmalloc_caches[type][aligned_idx]) > + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( > + kmalloc_info[aligned_idx].name[type], > + aligned_size, flags, 0, aligned_size); > + if (idx != aligned_idx) > + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; I would prefer detecting minimum kmalloc size in create_kmalloc_caches() in runtime instead of changing behavior of new_kmalloc_cache(). > /* > * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for > @@ -904,11 +920,8 @@ void __init create_kmalloc_caches(slab_flags_t flags) > struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; > > if (s) { > - kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( > - kmalloc_info[i].name[KMALLOC_DMA], > - kmalloc_info[i].size, > - SLAB_CACHE_DMA | flags, 0, > - kmalloc_info[i].size); > + new_kmalloc_cache(i, KMALLOC_DMA, > + SLAB_CACHE_DMA | flags); > } > } > #endif
On Thu, Apr 07, 2022 at 03:46:37AM +0000, Hyeonggon Yoo wrote: > On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > > --- a/mm/slab_common.c > > +++ b/mm/slab_common.c > > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > > } > > } > > > > -static void __init > > +unsigned int __weak arch_kmalloc_minalign(void) > > +{ > > + return ARCH_KMALLOC_MINALIGN; > > +} > > + > > As ARCH_KMALLOC_ALIGN and arch_kmalloc_minalign() may not be same after > patch 10, I think s/ARCH_KMALLOC_ALIGN/arch_kmalloc_minalign/g > for every user of it would be more correct? Not if the code currently using ARCH_KMALLOC_MINALIGN needs a constant. Yes, there probably are a few places where the code can cope with a dynamic arch_kmalloc_minalign() but there are two other cases where a constant is needed: 1. As a BUILD_BUG check because the code is storing some flags in the bottom bits of a pointer. A smaller ARCH_KMALLOC_MINALIGN works just fine here. 2. As a static alignment for DMA requirements. That's where the newly exposed ARCH_DMA_MINALIGN should be used. Note that this series doesn't make the situation any worse than before since ARCH_DMA_MINALIGN stays at 128 bytes for arm64. Current users can evolve to use a dynamic alignment in future patches. My main aim with this series is to be able to create kmalloc-64 caches on arm64. > > @@ -851,10 +860,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > > flags |= SLAB_ACCOUNT; > > } > > > > - kmalloc_caches[type][idx] = create_kmalloc_cache( > > - kmalloc_info[idx].name[type], > > - kmalloc_info[idx].size, flags, 0, > > - kmalloc_info[idx].size); > > + if (minalign > ARCH_KMALLOC_MINALIGN) { > > + aligned_size = ALIGN(aligned_size, minalign); > > + aligned_idx = __kmalloc_index(aligned_size, false); > > + } > > + > > + if (!kmalloc_caches[type][aligned_idx]) > > + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( > > + kmalloc_info[aligned_idx].name[type], > > + aligned_size, flags, 0, aligned_size); > > + if (idx != aligned_idx) > > + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; > > I would prefer detecting minimum kmalloc size in create_kmalloc_caches() > in runtime instead of changing behavior of new_kmalloc_cache(). That was my initial attempt but we have a couple of create_kmalloc_cache() (not *_caches) calls directly, one of them in mm/slab.c kmem_cache_init(). So I wanted all the minalign logic in a single place, hence I replaced the explicit create_kmalloc_cache() call with new_kmalloc_cache(). See this patch and patch 9 for some clean-up.
On Thu, Apr 07, 2022 at 09:50:23AM +0100, Catalin Marinas wrote: > On Thu, Apr 07, 2022 at 03:46:37AM +0000, Hyeonggon Yoo wrote: > > On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > > > --- a/mm/slab_common.c > > > +++ b/mm/slab_common.c > > > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > > > } > > > } > > > > > > -static void __init > > > +unsigned int __weak arch_kmalloc_minalign(void) > > > +{ > > > + return ARCH_KMALLOC_MINALIGN; > > > +} > > > + > > > > As ARCH_KMALLOC_ALIGN and arch_kmalloc_minalign() may not be same after > > patch 10, I think s/ARCH_KMALLOC_ALIGN/arch_kmalloc_minalign/g > > for every user of it would be more correct? > > Not if the code currently using ARCH_KMALLOC_MINALIGN needs a constant. > Yes, there probably are a few places where the code can cope with a > dynamic arch_kmalloc_minalign() but there are two other cases where a > constant is needed: > > 1. As a BUILD_BUG check because the code is storing some flags in the > bottom bits of a pointer. A smaller ARCH_KMALLOC_MINALIGN works just > fine here. > > 2. As a static alignment for DMA requirements. That's where the newly > exposed ARCH_DMA_MINALIGN should be used. > > Note that this series doesn't make the situation any worse than before > since ARCH_DMA_MINALIGN stays at 128 bytes for arm64. Current users can > evolve to use a dynamic alignment in future patches. My main aim with > this series is to be able to create kmalloc-64 caches on arm64. AFAIK there are bunch of drivers that directly calls kmalloc(). It becomes tricky when e.g.) a driver allocates just 32 bytes, but architecture requires it to be 128-byte aligned. That's why everything allocated from kmalloc() need to be aligned in ARCH_DMA_MINALIGN. And It's too hard to update all of drivers that depends on this fact. So I'm yet skeptical on decoupling ARCH_DMA/KMALLOC_MINALIGN. Instead of decoupling it, I'm more into dynamically decreasing it. Please kindly let me know If I'm missing something ;-) > > > @@ -851,10 +860,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > > > flags |= SLAB_ACCOUNT; > > > } > > > > > > - kmalloc_caches[type][idx] = create_kmalloc_cache( > > > - kmalloc_info[idx].name[type], > > > - kmalloc_info[idx].size, flags, 0, > > > - kmalloc_info[idx].size); > > > + if (minalign > ARCH_KMALLOC_MINALIGN) { > > > + aligned_size = ALIGN(aligned_size, minalign); > > > + aligned_idx = __kmalloc_index(aligned_size, false); > > > + } > > > + > > > + if (!kmalloc_caches[type][aligned_idx]) > > > + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( > > > + kmalloc_info[aligned_idx].name[type], > > > + aligned_size, flags, 0, aligned_size); > > > + if (idx != aligned_idx) > > > + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; > > > > I would prefer detecting minimum kmalloc size in create_kmalloc_caches() > > in runtime instead of changing behavior of new_kmalloc_cache(). > > That was my initial attempt but we have a couple of > create_kmalloc_cache() (not *_caches) calls directly, one of them in > mm/slab.c kmem_cache_init(). So I wanted all the minalign logic in a > single place, hence I replaced the explicit create_kmalloc_cache() call > with new_kmalloc_cache(). See this patch and patch 9 for some clean-up. > > -- > Catalin
On Thu, Apr 07, 2022 at 06:18:16PM +0900, Hyeonggon Yoo wrote: > On Thu, Apr 07, 2022 at 09:50:23AM +0100, Catalin Marinas wrote: > > On Thu, Apr 07, 2022 at 03:46:37AM +0000, Hyeonggon Yoo wrote: > > > On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > > > > --- a/mm/slab_common.c > > > > +++ b/mm/slab_common.c > > > > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > > > > } > > > > } > > > > > > > > -static void __init > > > > +unsigned int __weak arch_kmalloc_minalign(void) > > > > +{ > > > > + return ARCH_KMALLOC_MINALIGN; > > > > +} > > > > + > > > > > > As ARCH_KMALLOC_ALIGN and arch_kmalloc_minalign() may not be same after > > > patch 10, I think s/ARCH_KMALLOC_ALIGN/arch_kmalloc_minalign/g > > > for every user of it would be more correct? > > > > Not if the code currently using ARCH_KMALLOC_MINALIGN needs a constant. > > Yes, there probably are a few places where the code can cope with a > > dynamic arch_kmalloc_minalign() but there are two other cases where a > > constant is needed: > > > > 1. As a BUILD_BUG check because the code is storing some flags in the > > bottom bits of a pointer. A smaller ARCH_KMALLOC_MINALIGN works just > > fine here. > > > > 2. As a static alignment for DMA requirements. That's where the newly > > exposed ARCH_DMA_MINALIGN should be used. > > > > Note that this series doesn't make the situation any worse than before > > since ARCH_DMA_MINALIGN stays at 128 bytes for arm64. Current users can > > evolve to use a dynamic alignment in future patches. My main aim with > > this series is to be able to create kmalloc-64 caches on arm64. > > AFAIK there are bunch of drivers that directly calls kmalloc(). Well, lots of drivers call kmalloc() ;). > It becomes tricky when e.g.) a driver allocates just 32 bytes, > but architecture requires it to be 128-byte aligned. That's the current behaviour, a 32 byte allocation would return an object from kmalloc-128. I want to reduce this to at least kmalloc-64 (or smaller) if the CPU/SoC allows it. > That's why everything allocated from kmalloc() need to be aligned in > ARCH_DMA_MINALIGN. I don't get your conclusion here. Would you mind explaining? > So I'm yet skeptical on decoupling ARCH_DMA/KMALLOC_MINALIGN. Instead > of decoupling it, I'm more into dynamically decreasing it. The reason for decoupling is mostly that there are some static uses of ARCH_KMALLOC_MINALIGN as per point 1 above. The other is the __assume_kmalloc_alignment attribute. We shouldn't have such assumed alignment larger than what a dynamic kmalloc() would return. To me it makes a lot more sense for ARCH_KMALLOC_MINALIGN to be the minimum guaranteed in a kernel build but kmalloc() returning a larger alignment at run-time than the other way around. Thanks.
On Thu, Apr 07, 2022 at 10:35:04AM +0100, Catalin Marinas wrote: > On Thu, Apr 07, 2022 at 06:18:16PM +0900, Hyeonggon Yoo wrote: > > On Thu, Apr 07, 2022 at 09:50:23AM +0100, Catalin Marinas wrote: > > > On Thu, Apr 07, 2022 at 03:46:37AM +0000, Hyeonggon Yoo wrote: > > > > On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > > > > > --- a/mm/slab_common.c > > > > > +++ b/mm/slab_common.c > > > > > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > > > > > } > > > > > } > > > > > > > > > > -static void __init > > > > > +unsigned int __weak arch_kmalloc_minalign(void) > > > > > +{ > > > > > + return ARCH_KMALLOC_MINALIGN; > > > > > +} > > > > > + > > > > > > > > As ARCH_KMALLOC_ALIGN and arch_kmalloc_minalign() may not be same after > > > > patch 10, I think s/ARCH_KMALLOC_ALIGN/arch_kmalloc_minalign/g > > > > for every user of it would be more correct? > > > > > > Not if the code currently using ARCH_KMALLOC_MINALIGN needs a constant. > > > Yes, there probably are a few places where the code can cope with a > > > dynamic arch_kmalloc_minalign() but there are two other cases where a > > > constant is needed: > > > > > > 1. As a BUILD_BUG check because the code is storing some flags in the > > > bottom bits of a pointer. A smaller ARCH_KMALLOC_MINALIGN works just > > > fine here. > > > > > > 2. As a static alignment for DMA requirements. That's where the newly > > > exposed ARCH_DMA_MINALIGN should be used. > > > > > > Note that this series doesn't make the situation any worse than before > > > since ARCH_DMA_MINALIGN stays at 128 bytes for arm64. Current users can > > > evolve to use a dynamic alignment in future patches. My main aim with > > > this series is to be able to create kmalloc-64 caches on arm64. > > > > AFAIK there are bunch of drivers that directly calls kmalloc(). > > Well, lots of drivers call kmalloc() ;). > > > It becomes tricky when e.g.) a driver allocates just 32 bytes, > > but architecture requires it to be 128-byte aligned. > > That's the current behaviour, a 32 byte allocation would return an > object from kmalloc-128. I want to reduce this to at least kmalloc-64 > (or smaller) if the CPU/SoC allows it. Yeah I agree the change is worth :) Thanks for the work. > > That's why everything allocated from kmalloc() need to be aligned in > > ARCH_DMA_MINALIGN. > > I don't get your conclusion here. Would you mind explaining? What I wanted to say was that, why ARCH_DMA_MINALIGN should be different from ARCH_KMALLOC_MINALIGN. I thought the two were basically same thing. Instead of decoupling them, I thought just decreasing them in runtime makes more sense. > > So I'm yet skeptical on decoupling ARCH_DMA/KMALLOC_MINALIGN. Instead > > of decoupling it, I'm more into dynamically decreasing it. > > The reason for decoupling is mostly that there are some static uses of > ARCH_KMALLOC_MINALIGN as per point 1 above. The other is the > __assume_kmalloc_alignment attribute. We shouldn't have such assumed > alignment larger than what a dynamic kmalloc() would return. To me it > makes a lot more sense for ARCH_KMALLOC_MINALIGN to be the minimum > guaranteed in a kernel build but kmalloc() returning a larger alignment > at run-time than the other way around. But yeah, considering the problems you mentioned, it seems unavoidable to decouple them. Thank you for explanation and I will review slab part soon. > Thanks. > > -- > Catalin
On Tue, Apr 05, 2022 at 02:57:56PM +0100, Catalin Marinas wrote: > ARCH_KMALLOC_MINALIGN represents the minimum guaranteed kmalloc() > alignment but an architecture may require a larger run-time alignment. > Do not create kmalloc caches smaller than arch_kmalloc_minalign(). > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > --- > include/linux/slab.h | 2 ++ > mm/slab.c | 6 +----- > mm/slab.h | 2 ++ > mm/slab_common.c | 33 +++++++++++++++++++++++---------- > 4 files changed, 28 insertions(+), 15 deletions(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index d58211bdeceb..2137dba85691 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -332,6 +332,8 @@ enum kmalloc_cache_type { > extern struct kmem_cache * > kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1]; > > +unsigned int arch_kmalloc_minalign(void); > + > /* > * Define gfp bits that should not be set for KMALLOC_NORMAL. > */ > diff --git a/mm/slab.c b/mm/slab.c > index b04e40078bdf..4aaeeb9c994d 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -1256,11 +1256,7 @@ void __init kmem_cache_init(void) > * Initialize the caches that provide memory for the kmem_cache_node > * structures first. Without this, further allocations will bug. > */ > - kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache( > - kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL], > - kmalloc_info[INDEX_NODE].size, > - ARCH_KMALLOC_FLAGS, 0, > - kmalloc_info[INDEX_NODE].size); > + new_kmalloc_cache(INDEX_NODE, KMALLOC_NORMAL, ARCH_KMALLOC_FLAGS); > slab_state = PARTIAL_NODE; > setup_kmalloc_cache_index_table(); > > diff --git a/mm/slab.h b/mm/slab.h > index fd7ae2024897..e9238406602a 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -283,6 +283,8 @@ int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); > struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size, > slab_flags_t flags, unsigned int useroffset, > unsigned int usersize); > +void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, > + slab_flags_t flags); > extern void create_boot_cache(struct kmem_cache *, const char *name, > unsigned int size, slab_flags_t flags, > unsigned int useroffset, unsigned int usersize); > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 6ee64d6208b3..594d8a8a68d0 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) > } > } > > -static void __init > +unsigned int __weak arch_kmalloc_minalign(void) > +{ > + return ARCH_KMALLOC_MINALIGN; > +} > + > +void __init > new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > { > + unsigned int minalign = arch_kmalloc_minalign(); > + unsigned int aligned_size = kmalloc_info[idx].size; > + int aligned_idx = idx; > + > if (type == KMALLOC_RECLAIM) { > flags |= SLAB_RECLAIM_ACCOUNT; > } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { > @@ -851,10 +860,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) > flags |= SLAB_ACCOUNT; > } > > - kmalloc_caches[type][idx] = create_kmalloc_cache( > - kmalloc_info[idx].name[type], > - kmalloc_info[idx].size, flags, 0, > - kmalloc_info[idx].size); > + if (minalign > ARCH_KMALLOC_MINALIGN) { > + aligned_size = ALIGN(aligned_size, minalign); > + aligned_idx = __kmalloc_index(aligned_size, false); > + } > + > + if (!kmalloc_caches[type][aligned_idx]) > + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( > + kmalloc_info[aligned_idx].name[type], > + aligned_size, flags, 0, aligned_size); > + if (idx != aligned_idx) > + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; > > /* > * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for > @@ -904,11 +920,8 @@ void __init create_kmalloc_caches(slab_flags_t flags) > struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; > > if (s) { > - kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( > - kmalloc_info[i].name[KMALLOC_DMA], > - kmalloc_info[i].size, > - SLAB_CACHE_DMA | flags, 0, > - kmalloc_info[i].size); > + new_kmalloc_cache(i, KMALLOC_DMA, > + SLAB_CACHE_DMA | flags); > } > } > #endif Looks good to me. Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> And works fine with SLAB/SLUB/SLOB on my arm64 machine. Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Thanks!
diff --git a/include/linux/slab.h b/include/linux/slab.h index d58211bdeceb..2137dba85691 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -332,6 +332,8 @@ enum kmalloc_cache_type { extern struct kmem_cache * kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1]; +unsigned int arch_kmalloc_minalign(void); + /* * Define gfp bits that should not be set for KMALLOC_NORMAL. */ diff --git a/mm/slab.c b/mm/slab.c index b04e40078bdf..4aaeeb9c994d 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1256,11 +1256,7 @@ void __init kmem_cache_init(void) * Initialize the caches that provide memory for the kmem_cache_node * structures first. Without this, further allocations will bug. */ - kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache( - kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL], - kmalloc_info[INDEX_NODE].size, - ARCH_KMALLOC_FLAGS, 0, - kmalloc_info[INDEX_NODE].size); + new_kmalloc_cache(INDEX_NODE, KMALLOC_NORMAL, ARCH_KMALLOC_FLAGS); slab_state = PARTIAL_NODE; setup_kmalloc_cache_index_table(); diff --git a/mm/slab.h b/mm/slab.h index fd7ae2024897..e9238406602a 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -283,6 +283,8 @@ int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size, slab_flags_t flags, unsigned int useroffset, unsigned int usersize); +void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, + slab_flags_t flags); extern void create_boot_cache(struct kmem_cache *, const char *name, unsigned int size, slab_flags_t flags, unsigned int useroffset, unsigned int usersize); diff --git a/mm/slab_common.c b/mm/slab_common.c index 6ee64d6208b3..594d8a8a68d0 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -838,9 +838,18 @@ void __init setup_kmalloc_cache_index_table(void) } } -static void __init +unsigned int __weak arch_kmalloc_minalign(void) +{ + return ARCH_KMALLOC_MINALIGN; +} + +void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) { + unsigned int minalign = arch_kmalloc_minalign(); + unsigned int aligned_size = kmalloc_info[idx].size; + int aligned_idx = idx; + if (type == KMALLOC_RECLAIM) { flags |= SLAB_RECLAIM_ACCOUNT; } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) { @@ -851,10 +860,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags) flags |= SLAB_ACCOUNT; } - kmalloc_caches[type][idx] = create_kmalloc_cache( - kmalloc_info[idx].name[type], - kmalloc_info[idx].size, flags, 0, - kmalloc_info[idx].size); + if (minalign > ARCH_KMALLOC_MINALIGN) { + aligned_size = ALIGN(aligned_size, minalign); + aligned_idx = __kmalloc_index(aligned_size, false); + } + + if (!kmalloc_caches[type][aligned_idx]) + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache( + kmalloc_info[aligned_idx].name[type], + aligned_size, flags, 0, aligned_size); + if (idx != aligned_idx) + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx]; /* * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for @@ -904,11 +920,8 @@ void __init create_kmalloc_caches(slab_flags_t flags) struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; if (s) { - kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( - kmalloc_info[i].name[KMALLOC_DMA], - kmalloc_info[i].size, - SLAB_CACHE_DMA | flags, 0, - kmalloc_info[i].size); + new_kmalloc_cache(i, KMALLOC_DMA, + SLAB_CACHE_DMA | flags); } } #endif
ARCH_KMALLOC_MINALIGN represents the minimum guaranteed kmalloc() alignment but an architecture may require a larger run-time alignment. Do not create kmalloc caches smaller than arch_kmalloc_minalign(). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> --- include/linux/slab.h | 2 ++ mm/slab.c | 6 +----- mm/slab.h | 2 ++ mm/slab_common.c | 33 +++++++++++++++++++++++---------- 4 files changed, 28 insertions(+), 15 deletions(-)