mm/vmalloc: Do not warn on -ENOMEM from va_alloc()
Subsystems (2)
Uladzislau Rezki (Sony)
maintainerPATCH 1/1 mm/vmalloc: Do not warn on -ENOMEM from va_alloc()
Since vmalloc() accepts non-blocking GFP flags, allocation requests may fail when callers pass restrictive GFP masks.
va_clip() may return -ENOMEM when its GFP_NOWAIT fallback allocation fails during NE_FIT_TYPE splitting. This is an expected failure, so va_alloc() should return the error without triggering a kernel splat.
--- mm/vmalloc.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
mm/vmalloc.c +6 -7
@@ -1817,8 +1817,10 @@ va_alloc(struct vmap_area *va,/* Update the free vmap_area. */ ret =va_clip (root, head, va, nva_start_addr, size); -if (WARN_ON_ONCE (ret)) +if (ret) { +WARN_ON_ONCE (ret != -ENOMEM );return ret; + }return nva_start_addr; }
@@ -1891,12 +1893,9 @@ preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node)/* * Preload this CPU with one extra vmap_area object. It is used -* when fit type of free area is NE_FIT_TYPE. It guarantees that -* a CPU that does an allocation is preloaded. -* -* We do it in non-atomic context, thus it allows us to use more -* permissive allocation masks to be more stable under low memory -* condition and high memory pressure. +* when fit type of free area is NE_FIT_TYPE. It is best effort +* pre-loading. If it fails va_clip() may return -ENOMEM from its +* GFP_NOWAIT fallback. */ if (!this_cpu_read (ne_fit_preload_node)) va =kmem_cache_alloc_node (vmap_area_cachep, gfp_mask, node);
Signature · 1 line
2.47.3
Quoted 7 lines · Uladzislau Rezki (Sony)
Since
vmalloc()accepts non-blocking GFP flags, allocation requests may fail when callers pass restrictive GFP masks.
va_clip()may return-ENOMEMwhen itsGFP_NOWAITfallback allocation fails duringNE_FIT_TYPEsplitting. This is an expected failure, sova_alloc()should return the error without triggering a kernel splat.
Dropping WARN_ON_ONCE() just for -ENOMEM while preserving this warning for other returned errors does make sense.
Quoted 2 lines
Reported-by [email protected]
Very small nit.
If there is actual link for the problem report, probably it could be added as an Link: or Closes: here.
Quoted 1 line
Signed-off-by Uladzislau Rezki (Sony) <[email protected]>
Quoted 39 lines
--- mm/vmalloc.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)mm/vmalloc.c +6
-7@@ -1817,8 +1817,10 @@ va_alloc(struct vmap_area *va,/* Update the free vmap_area. */ ret =va_clip (root, head, va, nva_start_addr, size); -if (WARN_ON_ONCE (ret)) +if (ret) { +WARN_ON_ONCE (ret != -ENOMEM );return ret; + }return nva_start_addr; }@@ -1891,12 +1893,9 @@ preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node)/* * Preload this CPU with one extra vmap_area object. It is used -* when fit type of free area is NE_FIT_TYPE. It guarantees that -* a CPU that does an allocation is preloaded. -* -* We do it in non-atomic context, thus it allows us to use more -* permissive allocation masks to be more stable under low memory -* condition and high memory pressure. +* when fit type of free area is NE_FIT_TYPE. It is best effort +* pre-loading. If it fails va_clip() may return -ENOMEM from its +* GFP_NOWAIT fallback. */ if (!this_cpu_read (ne_fit_preload_node)) va =kmem_cache_alloc_node (vmap_area_cachep, gfp_mask, node);Signature · 1 line
2.47.3
Uladzislau Rezki
maintainerQuoted 13 lines · Anshuman Khandual
Quoted 7 lines · Uladzislau Rezki (Sony)
Since
vmalloc()accepts non-blocking GFP flags, allocation requests may fail when callers pass restrictive GFP masks.
va_clip()may return-ENOMEMwhen itsGFP_NOWAITfallback allocation fails duringNE_FIT_TYPEsplitting. This is an expected failure, sova_alloc()should return the error without triggering a kernel splat.Dropping
WARN_ON_ONCE()just for-ENOMEMwhile preserving this warning for other returned errors does make sense.Quoted 1 line
Quoted 7 lines
Quoted 1 line
Reported-by [email protected]Very small nit.
If there is actual link for the problem report, probably it could be added as an Link: or Closes: here.
I hope Andrew can help here. If not i will resend!
Thank you!
--
Uladzislau Rezki
Quoted 36 lines · Uladzislau Rezki (Sony)
Since
vmalloc()accepts non-blocking GFP flags, allocation requests may fail when callers pass restrictive GFP masks.
va_clip()may return-ENOMEMwhen itsGFP_NOWAITfallback allocation fails duringNE_FIT_TYPEsplitting. This is an expected failure, sova_alloc()should return the error without triggering a kernel splat.Reported-by [email protected]Signed-off-by Uladzislau Rezki (Sony) <[email protected]>--- mm/vmalloc.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)mm/vmalloc.c +3
-3@@ -1817,8 +1817,10 @@ va_alloc(struct vmap_area *va,/* Update the free vmap_area. */ ret =va_clip (root, head, va, nva_start_addr, size); -if (WARN_ON_ONCE (ret)) +if (ret) { +WARN_ON_ONCE (ret != -ENOMEM );return ret; + }return nva_start_addr; }@@ -1891,12 +1893,9 @@ preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node)/* * Preload this CPU with one extra vmap_area object. It is used -* when fit type of free area is NE_FIT_TYPE. It guarantees that -* a CPU that does an allocation is preloaded.
mm/vmalloc.c preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node) · line 1901
Quoted 10 lines
mm/vmalloc.c +3
-4-* -* We do it in non-atomic context, thus it allows us to use more -* permissive allocation masks to be more stable under low memory -* condition and high memory pressure. +* when fit type of free area is NE_FIT_TYPE. It is best effort +* pre-loading. If it fails va_clip() may return -ENOMEM from its +* GFP_NOWAIT fallback. */ if (!this_cpu_read (ne_fit_preload_node)) va =kmem_cache_alloc_node (vmap_area_cachep, gfp_mask, node);
LGTM,