Re: [PATCH v2 0/4] debug_pagealloc improvements through page_owner
On Thu, 22 Aug 2019 16:03:44 -0700 Andrew Morton wrote: > On Tue, 20 Aug 2019 15:18:24 +0200 Vlastimil Babka wrote: > > > v2: also fix THP split handling (added Patch 1) per Kirill > > > > The debug_pagealloc functionality serves a similar purpose on the page > > allocator level that slub_debug does on the kmalloc level, which is to > > detect > > bad users. One notable feature that slub_debug has is storing stack traces > > of > > who last allocated and freed the object. On page level we track allocations > > via > > page_owner, but that info is discarded when freeing, and we don't track > > freeing > > at all. This series improves those aspects. With both debug_pagealloc and > > page_owner enabled, we can then get bug reports such as the example in > > Patch 4. > > > > SLUB debug tracking additionaly stores cpu, pid and timestamp. This could be > > added later, if deemed useful enough to justify the additional page_ext > > structure size. > > Thanks. I split [1/1] out of the series as a bugfix and turned this > into a three-patch series. > None of which anyone has yet reviewed :(
Re: [PATCH v2 0/4] debug_pagealloc improvements through page_owner
On Tue, 20 Aug 2019 15:18:24 +0200 Vlastimil Babka wrote: > v2: also fix THP split handling (added Patch 1) per Kirill > > The debug_pagealloc functionality serves a similar purpose on the page > allocator level that slub_debug does on the kmalloc level, which is to detect > bad users. One notable feature that slub_debug has is storing stack traces of > who last allocated and freed the object. On page level we track allocations > via > page_owner, but that info is discarded when freeing, and we don't track > freeing > at all. This series improves those aspects. With both debug_pagealloc and > page_owner enabled, we can then get bug reports such as the example in Patch > 4. > > SLUB debug tracking additionaly stores cpu, pid and timestamp. This could be > added later, if deemed useful enough to justify the additional page_ext > structure size. Thanks. I split [1/1] out of the series as a bugfix and turned this into a three-patch series.
[PATCH v2 0/4] debug_pagealloc improvements through page_owner
v2: also fix THP split handling (added Patch 1) per Kirill The debug_pagealloc functionality serves a similar purpose on the page allocator level that slub_debug does on the kmalloc level, which is to detect bad users. One notable feature that slub_debug has is storing stack traces of who last allocated and freed the object. On page level we track allocations via page_owner, but that info is discarded when freeing, and we don't track freeing at all. This series improves those aspects. With both debug_pagealloc and page_owner enabled, we can then get bug reports such as the example in Patch 4. SLUB debug tracking additionaly stores cpu, pid and timestamp. This could be added later, if deemed useful enough to justify the additional page_ext structure size. Vlastimil Babka (4): mm, page_owner: handle THP splits correctly mm, page_owner: record page owner for each subpage mm, page_owner: keep owner info when freeing the page mm, page_owner, debug_pagealloc: save and dump freeing stack trace .../admin-guide/kernel-parameters.txt | 2 + include/linux/page_ext.h | 1 + mm/Kconfig.debug | 4 +- mm/huge_memory.c | 4 + mm/page_owner.c | 123 +- 5 files changed, 100 insertions(+), 34 deletions(-) -- 2.22.0
