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b=AtbQWd/RyZIQcaJSOx4arO+G10/M9zPE282t83jiUPnxcFMILI/MR5c98mRbJf8L1 1pXTATvUmoZmucTydvz2d3g18BgZz/thVtXTRpqMuILL7E5tjZTveHb+IawsOIhY9Z ZCZR+vhM8poY6rmI3ZhSS2LZllcI9jEFLl6Fl0Z8A8qQIDUFgsVSBp4YDvdXANnlLH rfqbOeJXUC4hK6qHvY8yh/6vH65kg9ad1AB+kMwWNzkRn89CoShs5r7ux6lkVKuIQg FQ1s1nUBFaZOg2uxuF8v/vZOxIaQY7qPMHVtXbZ0r/JHUMBlP7WDog9T338kfKKYtx uxpjrUIn73aLA== Date: Mon, 12 Oct 2026 13:58:18 +0100 From: "Lorenzo Stoakes (ARM)" To: Gregory Price Cc: albin_yang@163.com, akpm@linux-foundation.org, liam@infradead.org, david@kernel.org, vbabka@kernel.org, jannh@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, albinwyang@tencent.com Subject: Re: [PATCH] mm/madvise: add cond_resched() in THP branch of madvise_cold_or_pageout_pte_range() Message-ID: References: <20261010024042.4070048-1-albin_yang@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 100B7120006 X-Rspam-User: X-Stat-Signature: qyx1mjqbjia761bw6ekjgff9kii845ub X-HE-Tag: 1791809904-474111 X-HE-Meta: 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 XtnRftEL maQdRq2BDYhQlgnXEdQ/zTrgoVw1Tv+SApCev4SzXf4SnezWpWuilQ6lTGB905JGwawWHziCCufqM9NQgT/h3bar+TqFAOjFjSy6j96h1C0MnAasXwEYj+MxbS4YPJ4j/jszM/zUZhtQ1MsmbbtW2qfVDbHPEV0ny7JUM8nlXYoN6iJJfWr7KvUw2RjIyTLw0Fn0hZAKYBW9Vn1JKjS/Na0arnCsULgf3ScB6hckYeO5Q4FTCs8h22JMhk+CgKlt9d+zBOo9Zl8K56YVv/7OAn6JWkhurUcllO5ymfvqeSW3QTd1ROKOs9qBson/pBJC0xmUs4w4csasti/vKyIqXHoRplF5eiQ7DK6z8Dy30FvViGoEyqEpgvpiMrC8jchOvXaJRAr0T/wboBdSw1rNxQSW7RN7GH/tdcKr3JcJrTj68sCglCSgHUlt4Vg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Oct 10, 2026 at 10:26:33AM -0400, Gregory Price wrote: > On Sat, Oct 10, 2026 at 10:40:42AM +0800, albin_yang@163.com wrote: > > From: Wei Yang > > > > Crash log: > > watchdog: BUG: soft lockup - CPU#63 stuck for 23s! [stress-ng-vm:1665914] > > ... > > Call trace: > > pmdp_invalidate+0x48/0x68 > > madvise_cold_or_pageout_pte_range+0x84c/0xb00 > > walk_pmd_range.isra.0+0x1ac/0x3b0 > > walk_pud_range+0x120/0x190 > > walk_pgd_range+0x170/0x1b8 > > __walk_page_range+0x184/0x198 > > walk_page_range_vma+0x94/0x128 > > madvise_cold+0xd8/0x198 > > madvise_vma_behavior+0x234/0x638 > > madvise_walk_vmas.constprop.0+0xdc/0x210 > > madvise_do_behavior+0xa8/0x328 > > do_madvise+0xd8/0x140 > > __arm64_sys_madvise+0x2c/0xe0 > > > > Signed-off-by: Wei Yang > > --- > > mm/madvise.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/madvise.c b/mm/madvise.c > > index eeee82cf2b3f..0755e6d99757 100644 > > --- a/mm/madvise.c > > +++ b/mm/madvise.c > > @@ -450,6 +450,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, > > spin_unlock(ptl); > > if (pageout) > > reclaim_pages(&folio_list); > > + cond_resched(); > > return 0; > > } > > > > This same improvement came naturally from refactoring the entire > function into a proper pagewalk structure: > > https://lore.kernel.org/linux-mm/20260922235830.2350770-10-gourry@gourry.net/ > > this function is really nasty. Nice! And thank you for looking at this horror show of a function. But yeah as Andrew said, need something for the backport, then your work can help eliminate the source of such things! :) > > ~Gregory -- Cheers, Lorenzo