JIRA: https://issues.redhat.com/browse/RHEL-64867
commit 414d0f45c316221acbf066658afdbae5b354a5cc
Author: Jens Axboe <axboe@kernel.dk>
Date: Wed Mar 20 15:19:44 2024 -0600
io_uring/alloc_cache: switch to array based caching
Currently lists are being used to manage this, but best practice is
usually to have these in an array instead as that it cheaper to manage.
Outside of that detail, games are also played with KASAN as the list
is inside the cached entry itself.
Finally, all users of this need a struct io_cache_entry embedded in
their struct, which is union'ized with something else in there that
isn't used across the free -> realloc cycle.
Get rid of all of that, and simply have it be an array. This will not
change the memory used, as we're just trading an 8-byte member entry
for the per-elem array size.
This reduces the overhead of the recycled allocations, and it reduces
the amount of code code needed to support recycling to about half of
what it currently is.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-64867
commit 0ae9b9a14d54bd0aa68c1e8bda9dd8e6346f1d87
Author: Jens Axboe <axboe@kernel.dk>
Date: Sat Mar 16 18:23:44 2024 -0600
io_uring/alloc_cache: shrink default max entries from 512 to 128
In practice, we just need to recycle a few elements for (by far) most
use cases. Shrink the total size down from 512 to 128, which should be
more than plenty.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-64867
commit 8ab3b09755d926afc3bdd2fadff7f159310440c2
Author: Andrey Konovalov <andreyknvl@gmail.com>
Date: Tue Dec 19 23:29:05 2023 +0100
io_uring: use mempool KASAN hook
Use the proper kasan_mempool_unpoison_object hook for unpoisoning cached
objects.
A future change might also update io_uring to check the return value of
kasan_mempool_poison_object to prevent double-free and invalid-free bugs.
This proves to be non-trivial with the current way io_uring caches
objects, so this is left out-of-scope of this series.
Link: https://lkml.kernel.org/r/eca18d6cbf676ed784f1a1f209c386808a8087c5.1703024586.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-64867
commit 280ec6ccb6422aa4a04f9ac4216ddcf055acc95d
Author: Andrey Konovalov <andreyknvl@gmail.com>
Date: Tue Dec 19 23:28:45 2023 +0100
kasan: rename kasan_slab_free_mempool to kasan_mempool_poison_object
Patch series "kasan: save mempool stack traces".
This series updates KASAN to save alloc and free stack traces for
secondary-level allocators that cache and reuse allocations internally
instead of giving them back to the underlying allocator (e.g. mempool).
As a part of this change, introduce and document a set of KASAN hooks:
bool kasan_mempool_poison_pages(struct page *page, unsigned int order);
void kasan_mempool_unpoison_pages(struct page *page, unsigned int order);
bool kasan_mempool_poison_object(void *ptr);
void kasan_mempool_unpoison_object(void *ptr, size_t size);
and use them in the mempool code.
Besides mempool, skbuff and io_uring also cache allocations and already
use KASAN hooks to poison those. Their code is updated to use the new
mempool hooks.
The new hooks save alloc and free stack traces (for normal kmalloc and
slab objects; stack traces for large kmalloc objects and page_alloc are
not supported by KASAN yet), improve the readability of the users' code,
and also allow the users to prevent double-free and invalid-free bugs; see
the patches for the details.
This patch (of 21):
Rename kasan_slab_free_mempool to kasan_mempool_poison_object.
kasan_slab_free_mempool is a slightly confusing name: it is unclear
whether this function poisons the object when it is freed into mempool or
does something when the object is freed from mempool to the underlying
allocator.
The new name also aligns with other mempool-related KASAN hooks added in
the following patches in this series.
Link: https://lkml.kernel.org/r/cover.1703024586.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/c5618685abb7cdbf9fb4897f565e7759f601da84.1703024586.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-12076
commit 69bbc6ade9d9d4e3c556cb83e77b6f3cd9ad3d18
Author: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue Apr 4 13:39:57 2023 +0100
io_uring/rsrc: add custom limit for node caching
The number of entries in the rsrc node cache is limited to 512, which
still seems unnecessarily large. Add per cache thresholds and set to
to 32 for the rsrc node cache.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d0cd538b944dac0bf878e276fc0199f21e6bccea.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-12076
commit e1fe7ee885dc0712e982ee465d9f8b96254c30c1
Author: Breno Leitao <leitao@debian.org>
Date: Thu Feb 23 08:43:53 2023 -0800
io_uring: Add KASAN support for alloc_caches
Add support for KASAN in the alloc_caches (apoll and netmsg_cache).
Thus, if something touches the unused caches, it will raise a KASAN
warning/exception.
It poisons the object when the object is put to the cache, and unpoisons
it when the object is gotten or freed.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230223164353.2839177-2-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-12076
commit efba1a9e653e107577a48157b5424878c46f2285
Author: Breno Leitao <leitao@debian.org>
Date: Thu Feb 23 08:43:52 2023 -0800
io_uring: Move from hlist to io_wq_work_node
Having cache entries linked using the hlist format brings no benefit, and
also requires an unnecessary extra pointer address per cache entry.
Use the internal io_wq_work_node single-linked list for the internal
alloc caches (async_msghdr and async_poll)
This is required to be able to use KASAN on cache entries, since we do
not need to touch unused (and poisoned) cache entries when adding more
entries to the list.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230223164353.2839177-2-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2068237
commit fd30d1cdcc4ff405fc54765edf2e11b03f2ed4f3
Author: Pavel Begunkov <asml.silence@gmail.com>
Date: Thu Mar 30 06:52:38 2023 -0600
io_uring: fix poll/netmsg alloc caches
We increase cache->nr_cached when we free into the cache but don't
decrease when we take from it, so in some time we'll get an empty
cache with cache->nr_cached larger than IO_ALLOC_CACHE_MAX, that fails
io_alloc_cache_put() and effectively disables caching.
Fixes: 9b797a37c4bd8 ("io_uring: add abstraction around apoll cache")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2068237
commit 9731bc9855dc169f27433fef3c4d0ff3496c512d
Author: Jens Axboe <axboe@kernel.dk>
Date: Thu Jul 7 14:20:54 2022 -0600
io_uring: impose max limit on apoll cache
Caches like this tend to grow to the peak size, and then never get any
smaller. Impose a max limit on the size, to prevent it from growing too
big.
A somewhat randomly chosen 512 is the max size we'll allow the cache
to get. If a batch of frees come in and would bring it over that, we
simply start kfree'ing the surplus.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2068237
commit 9b797a37c4bd83b03cedcfbd15852b836f5e562c
Author: Jens Axboe <axboe@kernel.dk>
Date: Thu Jul 7 14:16:20 2022 -0600
io_uring: add abstraction around apoll cache
In preparation for adding limits, and one more user, abstract out the
core bits of the allocation+free cache.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Jeff Moyer