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charset=UTF-8 X-Stat-Signature: r9zypkbqwjibfygwte7ucmg3mypzwqz9 X-Rspam-User: X-Rspamd-Queue-Id: E3AD01C0012 X-Rspamd-Server: rspam12 X-HE-Tag: 1772466808-712268 X-HE-Meta: U2FsdGVkX1917b1Myu0SrqdbUTAgt2oGqnj0yGJMum9pcbZdmC5U67KzWnv+PXtkcqqEaZRHNjCyY2GDtAwcgFlQzxkhUFYyyNdbAPnViaP51VXn9i6l6g1j7CkTvtpjD7OclfRpwP4VehMlMFIaMBJfyDpVZ2ARWxdth7ZuVgFon1CxPJ4h6VD0j633JJliL+xUCYb5cHzxflVvsYLe9UBnKWl5zrfKvpFsGXZGIDhAF/61LdlctltDwg0h3MY2wcK2H6+A+bnYa23CCDCaVB09u4oBz6pBo9qjBOXlpCtmeqJ//72L+fUmSVYUhpc05UUdCBO7kq4HETznXMnAJ5itH3tYFFC4GMW9GyHJS+TRS+9biRoiqLdaEpS3+DyOlZQCA0Aw7Umgt41TI4i+hnZ8GK5+Z73HoVtx8C31RGctD37WSv9EhHv2HOZ5bu/Ge+bou7wtcY7pxT/w72wJcAL2mXhrErHq4IUMp3NvRZR1l2usrn67mBD5Hx4+CSqJS8cFMyZyUlPdE26bOeRQoTiD1079oq7zb70sx/BeVsPXoHu7HMNklY6MZbqQRs6U30pTpPYhPzmp5pZswd5pxL+T2vLFPNQp09EBChrkCFQerDMt6x+FOTKmvmsPdlUtAtIb5RuktVtgVmqsUxT5SmdAnq4I3lScp6XssWqSvzhkLPkqb6yKXUYVzGRZm8p2bi57qW4xsXKEvtav7eAYXd1B/WMHwulMOhtfaxGRxweJe2kbPi1Dvt1NzkNj7p86m1EBe1nDg/EySblD2/fBC8o/4wMsM+0tcAO58DXrbiNiIzauIu3fXO7xma7owPKr2KKdfdhsKk/Bkh/eju4Hy8pGr4EK5veoTCQI2rNQ199s9yFTrRpiQGtvVsPFNGdM8AXgzd1XEMnnMjzpfLR51HMHGATitAr9SbJd5DX+ioa4RfKhvUaaLkeB7zuERFmu1PdxXpCcPxm0rVh7e5S uGsJoJaU OhjJ2XnpKUp62VtxxV0JTecHX7rELjqdw5bGXp0wOovORE+Mw+kKa+Bxz16gYrXN1s9CBptyjOlhcrs17I20dF0q70PKnMhZ5ZQtAFcvVLLTZrBk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Vlastimil Babka sheaf_flush_main() can be called from __pcs_replace_full_main() where the trylock can in theory fail, and pcs_flush_all() where it's not expected to and it would be actually a problem if it failed and left the main sheaf not flushed. To make this explicit, split the function into sheaf_flush_main() (using local_lock()) and sheaf_try_flush_main() (using local_trylock()) where both call __sheaf_flush_main_batch() to flush a single batch of objects. This will allow lockdep to verify our assumptions. Signed-off-by: Vlastimil Babka --- mm/slub.c | 47 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 37 insertions(+), 10 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 18c30872d196..12912b29f5bb 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2844,19 +2844,19 @@ static void __kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p); * object pointers are moved to a on-stack array under the lock. To bound the * stack usage, limit each batch to PCS_BATCH_MAX. * - * returns true if at least partially flushed + * Must be called with s->cpu_sheaves->lock locked, returns with the lock + * unlocked. + * + * Returns how many objects are remaining to be flushed */ -static bool sheaf_flush_main(struct kmem_cache *s) +static unsigned int __sheaf_flush_main_batch(struct kmem_cache *s) { struct slub_percpu_sheaves *pcs; unsigned int batch, remaining; void *objects[PCS_BATCH_MAX]; struct slab_sheaf *sheaf; - bool ret = false; -next_batch: - if (!local_trylock(&s->cpu_sheaves->lock)) - return ret; + lockdep_assert_held(this_cpu_ptr(&s->cpu_sheaves->lock)); pcs = this_cpu_ptr(s->cpu_sheaves); sheaf = pcs->main; @@ -2874,10 +2874,37 @@ static bool sheaf_flush_main(struct kmem_cache *s) stat_add(s, SHEAF_FLUSH, batch); - ret = true; + return remaining; +} - if (remaining) - goto next_batch; +static void sheaf_flush_main(struct kmem_cache *s) +{ + unsigned int remaining; + + do { + local_lock(&s->cpu_sheaves->lock); + + remaining = __sheaf_flush_main_batch(s); + + } while (remaining); +} + +/* + * Returns true if the main sheaf was at least partially flushed. + */ +static bool sheaf_try_flush_main(struct kmem_cache *s) +{ + unsigned int remaining; + bool ret = false; + + do { + if (!local_trylock(&s->cpu_sheaves->lock)) + return ret; + + ret = true; + remaining = __sheaf_flush_main_batch(s); + + } while (remaining); return ret; } @@ -5685,7 +5712,7 @@ __pcs_replace_full_main(struct kmem_cache *s, struct slub_percpu_sheaves *pcs, if (put_fail) stat(s, BARN_PUT_FAIL); - if (!sheaf_flush_main(s)) + if (!sheaf_try_flush_main(s)) return NULL; if (!local_trylock(&s->cpu_sheaves->lock)) --- base-commit: 27125df9a5d3b4cfd03bce3a8ec405a368cc9aae change-id: 20260211-b4-sheaf-flush-2eb99a9c8bfb Best regards, -- Vlastimil Babka