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Tue, 28 Nov 2023 14:28:56 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id OByqIij5ZWW3PQAAD6G6ig (envelope-from ); Tue, 28 Nov 2023 14:28:56 +0000 Date: Tue, 28 Nov 2023 15:28:55 +0100 From: Michal Hocko To: Gregory Price Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, arnd@arndb.de, tglx@linutronix.de, luto@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, tj@kernel.org, ying.huang@intel.com, Gregory Price Subject: Re: [RFC PATCH 02/11] mm/mempolicy: swap cond reference counting logic in do_get_mempolicy Message-ID: References: <20231122211200.31620-1-gregory.price@memverge.com> <20231122211200.31620-3-gregory.price@memverge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spamd-Bar: +++++++++++++++ X-Spam: Yes X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: D0536100005 X-Stat-Signature: p5f6sxwwmzaib7k4a7oy7c97ky13n8go X-HE-Tag: 1701181738-494404 X-HE-Meta: U2FsdGVkX1/w4/Ou+H8/JY38/cSu5ejB1Y0R61ZPDTDg0AJFLaiM5SWre0GxpjLOfJ23fC6HRI5Fsj1NKcz0AFzg9k0d2R7sbmDFyZiPm9kS25XoPHmDYMNQ7dDkkyS4OeD+lHS/b76cJ+tUDrtF19VdsYdjqhoRatldqFPDYWn4cYPRumPnNjhfUQ6sx7FlFtuZn2B+avxpDIOIRHGzGqqkH2w5lqTuuMCniIdbOsOS/rgjZJ+PMzMZTUZwXzao7lgxkrY68wT2U/eVdM1S4B08cyvTfYezdMfv+R4xz9+LI+O0gE0HWKzUZmN4+FpOOTzy8W6zrih6gFiFzIn0u/iKFE4veg5JJ6zSW7DVlcLSzrMBywgpZokWjpz/nVqHYG9p75g+bYjsQcuMMik5nHK67ODFn01KZdpfeO8Fqjlh0N8XrhHcIc0/j36YW39oxL/Wf0iKDifFA92aLg6RCREfni5WPmI/2HP41D4GKKCdr/Ii70dURUoYjLXoAEEK/Qdyf3/Sux9NZXLGFK1I25WgplYYWmBK3uuubK4aWPyE6A3kCWYei2hAUNrRJZRwY0gxui4XNfdoCvXy1eoIv/IYk69aVHxeqtoe24JQG04II5JPcBdZYBICCVKrcZyxO0NmcIjadGYg9v8srRBtXdLfsQKhNScdnQihB5Q5+G1JxeyCduQYS+UMbAQSanobJTKU3mKC7fQlzaTpPguUkL33AswFTLmitFy35xnuFbk7pvZ9c+sT4QrZ/RrQELXq3KHYScy8wFDexBn5T+BU7M+oQ4BJyFdDjVgLLCZO4LL9QBBb31uSIjmtzgvC6hQV9ppujQFnKmkwD4UsZc1PKYNCpWWlCMHtAJpGvErl863SYofKLrPt9zMFPh+P1jt/WEmswys/GbM+JbkeVrYKYo9dglMGgwe8RBX8fnDn+3VrZnxyWk0qEIhek0pRaWqh2MlK0PHlVAODw370On+ ahi+fN0K lMbaWFHqOGK+wInMqD1vYqQVe0TuxvUYRvm69aEasfHddBAVbXYWqyrRFhXwbOWMqMNMRgS2uERme6IT5LNhJmwPWF69xj1r/DiIjvKSJz9gVsn+k8KYD1/Dmb0P9kAnDuVW6KAm0Rl5dkTXaEWX+p5LXk8FrAQjNIv2cUX3tjmW56J6ty8hWLz1LGeFOhr1xRIxczx7lmRHjoyItFW16xzr0EiuGWI18Xyno X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: [restoring the CC list, I supect you didn't want this to be a private discussion] On Tue 28-11-23 09:10:18, Gregory Price wrote: > On Tue, Nov 28, 2023 at 03:07:10PM +0100, Michal Hocko wrote: > > On Wed 22-11-23 16:11:51, Gregory Price wrote: > > [...] > > > @@ -982,11 +991,11 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, > > > } > > > > > > out: > > > - mpol_cond_put(pol); > > > + mpol_put(pol); > > > if (vma) > > > mmap_read_unlock(mm); > > > if (pol_refcount) > > > - mpol_put(pol_refcount); > > > + mpol_cond_put(pol_refcount); > > > > Maybe I am just misreading the patch but pol_refcount should be always > > NULL with this patch > > > > earlier: > > + pol = pol_refcount = __get_vma_policy(vma, addr, &ilx); > > i can split this into two lines if preferred. > > If addr is not set, then yes pol_refcount is always null. My bad, missed that. Making that two lines would be easier to read but nothing I would insist on of course. -- Michal Hocko SUSE Labs