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b=XW/qXrnb4pX3o9W+wGI0W1ifJ0 NfQ+n+ZFMHfs6VA1ESmzMbKmE1LhTwYO6E5ioKclh1JV02ZMIgaDzq0GWDQGBY0gzF5M76ylnTxrC 7E83xUP/BpozMsICavLB6ZnfU1OU6LKx0Wj5aunbLpYvtUEeeieIU3m/Gz6cMFp6EOwENrODXCbf3 qOAhjJFrqtO3TTo1KdntZRMNWjDxPaXQbODeZrPCu7vO2kJTzJ2xG5HwK+Qr7Tfm/0zWjMzI9lyRr zfNSZ+lTmJAiOm3aESaWQv9TqyHj0lqJt/pwBZdfMkgX0LhFpjXGu24OPdJYs3yC349aEQjU01NgC TXGtBmgw==; Received: from 179-125-92-238-dinamico.pombonet.net.br ([179.125.92.238] helo=[127.0.0.1]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1wKav4-006sxt-Ta; Wed, 06 May 2026 14:00:02 +0200 From: Thadeu Lima de Souza Cascardo Date: Wed, 06 May 2026 08:58:24 -0300 Subject: [PATCH 1/2] mm/page_counter: decouple peak_reset from peak_write MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260506-dmem_peak-v1-1-8d803eb3449c@igalia.com> References: <20260506-dmem_peak-v1-0-8d803eb3449c@igalia.com> In-Reply-To: <20260506-dmem_peak-v1-0-8d803eb3449c@igalia.com> To: Tejun Heo , Johannes Weiner , =?utf-8?q?Michal_Koutn=C3=BD?= , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Jonathan Corbet , Shuah Khan , Maarten Lankhorst , Maxime Ripard , Natalie Vock , Tvrtko Ursulin Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org, Thadeu Lima de Souza Cascardo , kernel-dev@igalia.com X-Mailer: b4 0.16-dev-62088 X-Stat-Signature: im6cb9mn6g1yzerijin878qujcznqsqp X-Rspam-User: X-Rspamd-Queue-Id: B6042140010 X-Rspamd-Server: rspam07 X-HE-Tag: 1778068817-608593 X-HE-Meta: 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 XiVCh6At /3/R+l1E1FxZf7v1HczdNr57lhvQ5Nz3cVYteLm+GEf2+FgUU6QQg3VvKPRN7NvEtCsWY0epoTmi/Yse5PbJeLUtnL/jp0QeVQISEILIRJtSuTf5RdrfdkKag0BdZY8CNTltrUT3LDwcZ9Hq8L2zp9m3WzWQo8eqTeFBORNZy82xVUxw8mAONxTpJaga70JeHfGzLc6L9KVGxySNlnWgPMabIgh146qcjlyaFxbEy6sGWUjLm8BwsN0rVaHeQgbTozErlSnwi7RGXMPzpMJhKMK+C051nWrI7QVdKaE2yC6zpt6kjYawQV5RtXClJZJYDiUFqoFxlpdj3cqd8e51A4q0C9neVRxD/iER3XaDnnKPJmbk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Create a new function of_peak_reset that resets the page_counter peak for a given writer. This should allow it to be reused by other cgroups. Signed-off-by: Thadeu Lima de Souza Cascardo --- include/linux/cgroup-defs.h | 6 ++++++ kernel/cgroup/cgroup.c | 32 ++++++++++++++++++++++++++++++++ mm/memcontrol.c | 42 ++++++++---------------------------------- 3 files changed, 46 insertions(+), 34 deletions(-) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index f42563739d2e..a85044cb0553 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -22,6 +22,7 @@ #include #include #include +#include #ifdef CONFIG_CGROUPS @@ -868,11 +869,16 @@ struct cgroup_subsys { extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; extern bool cgroup_enable_per_threadgroup_rwsem; +#define OFP_PEAK_UNSET (((-1UL))) + struct cgroup_of_peak { unsigned long value; struct list_head list; }; +void of_peak_reset(struct cgroup_of_peak *ofp, struct page_counter *pc, + struct list_head *watchers); + /** * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups * @tsk: target task diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 45c0b1ed687a..9b98a5cccf0e 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1981,6 +1981,38 @@ struct cgroup_of_peak *of_peak(struct kernfs_open_file *of) return &ctx->peak; } +/** + * of_peak_reset - reset peak + * @ofp: open file context + * @pc: counter + * @watchers: list of other open file contexts + * + * This function updates all contexts in @watchers to the new usage of @pc. + * If @ofp is not in the list yet, that is, if its value is + * %OFP_PEAK_UNSET, it is added to @watchers list. + * + * A lock must be used to protect @watchers. + */ +void of_peak_reset(struct cgroup_of_peak *ofp, struct page_counter *pc, + struct list_head *watchers) +{ + unsigned long usage; + struct cgroup_of_peak *peer_ctx; + + usage = page_counter_read(pc); + WRITE_ONCE(pc->local_watermark, usage); + + list_for_each_entry(peer_ctx, watchers, list) + if (usage > peer_ctx->value) + WRITE_ONCE(peer_ctx->value, usage); + + /* initial write, register watcher */ + if (ofp->value == OFP_PEAK_UNSET) + list_add(&ofp->list, watchers); + + WRITE_ONCE(ofp->value, usage); +} + static void apply_cgroup_root_flags(unsigned int root_flags) { if (current->nsproxy->cgroup_ns == &init_cgroup_ns) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c03d4787d466..8754927070d3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4517,8 +4517,6 @@ static u64 memory_current_read(struct cgroup_subsys_state *css, return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE; } -#define OFP_PEAK_UNSET (((-1UL))) - static int peak_show(struct seq_file *sf, void *v, struct page_counter *pc) { struct cgroup_of_peak *ofp = of_peak(sf->private); @@ -4563,45 +4561,18 @@ static void peak_release(struct kernfs_open_file *of) spin_unlock(&memcg->peaks_lock); } -static ssize_t peak_write(struct kernfs_open_file *of, char *buf, size_t nbytes, - loff_t off, struct page_counter *pc, - struct list_head *watchers) +static ssize_t memory_peak_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) { - unsigned long usage; - struct cgroup_of_peak *peer_ctx; struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); struct cgroup_of_peak *ofp = of_peak(of); spin_lock(&memcg->peaks_lock); - - usage = page_counter_read(pc); - WRITE_ONCE(pc->local_watermark, usage); - - list_for_each_entry(peer_ctx, watchers, list) - if (usage > peer_ctx->value) - WRITE_ONCE(peer_ctx->value, usage); - - /* initial write, register watcher */ - if (ofp->value == OFP_PEAK_UNSET) - list_add(&ofp->list, watchers); - - WRITE_ONCE(ofp->value, usage); + of_peak_reset(ofp, &memcg->memory, &memcg->memory_peaks); spin_unlock(&memcg->peaks_lock); - return nbytes; } -static ssize_t memory_peak_write(struct kernfs_open_file *of, char *buf, - size_t nbytes, loff_t off) -{ - struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); - - return peak_write(of, buf, nbytes, off, &memcg->memory, - &memcg->memory_peaks); -} - -#undef OFP_PEAK_UNSET - static int memory_min_show(struct seq_file *m, void *v) { return seq_puts_memcg_tunable(m, @@ -5611,9 +5582,12 @@ static ssize_t swap_peak_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of)); + struct cgroup_of_peak *ofp = of_peak(of); - return peak_write(of, buf, nbytes, off, &memcg->swap, - &memcg->swap_peaks); + spin_lock(&memcg->peaks_lock); + of_peak_reset(ofp, &memcg->swap, &memcg->swap_peaks); + spin_unlock(&memcg->peaks_lock); + return nbytes; } static int swap_high_show(struct seq_file *m, void *v) -- 2.47.3